1  CRTL
   The complete HP C Run-Time Library (C RTL) needed for use with
   the HP C compiler is distributed with the OpenVMS operating
   system, which runs on Alpha, and Intel[R] Itanium[R] processors.
   HP OpenVMS Industry Standard 64 for Integrity Servers is the full
   product name of the OpenVMS operating system on Intel Itanium
   processors.

   The C RTL provides routines to perform input/output, character
   and string handling, mathematical computations, memory
   allocation, error detection, subprocess creation, system access,
   and emulation of selected UNIX[R] features. These routines are
   provided both in shared image and object module library form.

   The C RTL contains XPG4-compliant internationalization support,
   providing functions to help you develop software that can run in
   different languages and cultures.

   This online help describes the C RTL routines available with this
   version of the OpenVMS Alpha system.

   For help on the socket routines used for writing Internet
   application programs for the TCP/IP Services protocol, use the
   following:

   $ HELP TCPIP_Services Programming_Interfaces Sockets_API

   Also see the "HP TCP/IP Services for OpenVMS" product
   documentation.
 

2  Feature-Test_Macros
   Feature-test macros provide a means for writing portable
   programs. They ensure that the Compaq C RTL symbolic names used
   by a program do not clash with the symbolic names supplied by the
   implementation.

   The Compaq C RTL header files are coded to support the use of
   a number of feature-test macros. When an application defines a
   feature-test macro, the Compaq C RTL header files supply the
   symbols and prototypes defined by that feature-test macro and
   nothing else. If a program does not define such a macro, the
   Compaq C RTL header files define symbols without restriction.

   The feature-test macros supported by the Compaq C RTL fall into
   the following broad categories for controlling the visibility of
   symbols in header files according to the following:

   o  Standards

   o  Multiple-version support

   o  Compatibility
 

3  Standards_Macros
   The Compaq C RTL implements parts of the following standards:

   o  X/Open CAE Specification, System Interfaces and Headers, Issue
      4, Version 2, also known as XPG4 V2.

   o  X/Open CAE Specification, System Interfaces and Headers, Issue
      4, also known as XPG4.

   o  Standard for Information Technology - Portable Operating
      System Interface (POSIX) - Part 1: System Application Program
      Interface (API)-Amendment 2: Threads Extension [C Language],
      also known as POSIX 1003.1c-1995 or IEEE 1003.1c-1995.

   o  ISO/IEC 9945-2:1993 - Information Technology - Portable
      Operating System Interface (POSIX) - Part 2: Shell and
      Utilities, also known as ISO POSIX-2.

   o  ISO/IEC 9945-1:1990 - Information Technology - Portable
      Operating System Interface (POSIX) - Part 1: System
      Application Programming Interface (API) (C Language), also
      known as ISO POSIX-1.

   o  ANSI/ISO/IEC 9899:1999 - The C99 standard, published by ISO in
      December, 1999 and adopted as an ANSI standard in April, 2000.

   o  ISO/IEC 9899:1990-1994 - Programming Languages - C, Amendment
      1: Integrity, also known as ISO C, Amendment 1.

   o  ISO/IEC 9899:1990 - Programming Languages - C, also known as
      ISO C. The normative part is the same as X3.159-1989, American
      National Standard for Information Systems - Programming
      Language C, also known as ANSI C.
 

3  Selecting_a_Standard
   You can define a feature-test macro to select each standard. You
   can do this either with a #define preprocessor directive in your
   C source before the inclusion of any header file, or with the
   /DEFINE qualifier on the CC command line.

   Features not defined by one of the previously named standards are
   considered Compaq C extensions and are selected by not defining
   any standards-related, feature-test macros.

   If you do not explicitly define feature test macros to control
   header file definitions, you implicitly include all defined
   symbols as well as Compaq C extensions.
 

4  _XOPEN_SOURCE_EXTENDED
   Makes visible XPG4-extended features, including traditional UNIX
   based interfaces not previously adopted by X/Open.

   Standard Selected: XPG4 V2

   Other Standards Implied: XPG4, ISO POSIX-2, ISO POSIX-1, ANSI C
 

4  _XOPEN_SOURCE
   Makes visible XPG4 standard symbols and causes _POSIX_C_SOURCE
   to be set to 2 if it is not already defined with a value greater
   than 2.

   Notes:

   o  Where the ISO C Amendment 1 includes symbols not specified by
      XPG4, defining __STDC_VERSION__  == 199409 and _XOPEN_SOURCE
      (or _XOPEN_SOURCE_EXTENDED) selects both ISO C and XPG4 APIs.
      Conflicts that arise when compiling with both XPG4 and ISO C
      Amendment 1 resolve in favor of ISO C Amendment 1.

   o  Where XPG4 extends the ISO C Amendment 1, defining _XOPEN_
      SOURCE or _XOPEN_SOURCE_EXTENDED selects ISO C APIs as well as
      the XPG4 extensions available in the header file. This mode of
      compilation makes XPG4 extensions visible.

   Standard Selected: XPG4

   Other Standards Implied: XPG4, ISO POSIX-2, ISO POSIX-1, ANSI C
 

4  _POSIX_C_SOURCE==199506
   Header files defined by ANSI C make visible those symbols
   required by IEEE 1003.1c-1995.

   Standard Selected: IEEE 1003.1c-1995

   Other Standards Implied: ISO POSIX-2, ISO POSIX-1, ANSI C
 

4  _POSIX_C_SOURCE==2
   Header files defined by ANSI C make visible those symbols
   required by ISO POSIX-2 plus those required by ISO POSIX-1.

   Standard Selected: ISO POSIX-2

   Other Standards Implied: ISO POSIX-1, ANSI C
 

4  _POSIX_C_SOURCE==1
   Header files defined by ANSI C make visible those symbols
   required by ISO POSIX-1.

   Standard Selected: ISO POSIX-1

   Other Standards Implied: ANSI C
 

4  _STDC_VERSION__==199409_
   Makes ISO C Amendment 1 symbols visible.

   Standard Selected: ISO C Amendment 1

   Other Standards Implied: ANSI C
 

4  _ANSI_C_SOURCE
   Makes ANSI C standard symbols visible.

   Standard Selected: ANSI C

   Other Standards Implied: None.
 

4  Interactions_with_the_/STANDARD_Qualifier
   The /STANDARD qualifier selects the dialect of the C language
   supported.

   With the exception of /STANDARD=ANSI89 and /STANDARD=ISOC94, the
   selection of C dialect and the selection of Compaq C RTL APIs to
   use are independent choices. All other values for /STANDARD cause
   the entire set of APIs to be available, including extensions.

   Specifying /STANDARD=ANSI89 restricts the default API set to the
   ANSI C set. In this case, to select a broader set of APIs, you
   must also specify the appropriate feature-test macro. To select
   the ANSI C dialect and all APIs, including extensions, undefine
   __HIDE_FORBIDDEN_NAMES before including any header file.

   Compiling with /STANDARD=ISOC94 sets __STDC_VERSION__  to
   199409. Conflicts that arise when compiling with both XPG4 and
   ISO C Amendment 1 resolve in favor of ISO C Amendment 1. XPG4
   extensions to ISO C Amendment 1 are selected by defining _XOPEN_
   SOURCE.

   The following examples help clarify these rules:

   o  The fdopen function is an ISO POSIX-1 extension to <stdio.h>.
      Therefore, <stdio.h> defines fdopen only if one or more of the
      following is true:

      -  The program including it is not compiled in strict ANSI C
         mode (/STANDARD=ANSI89).

      -  _POSIX_C_SOURCE is defined as 1 or greater.

      -  _XOPEN_SOURCE is defined.

      -  _XOPEN_SOURCE_EXTENDED is defined.

   o  The popen function is an ISO POSIX-2 extension to <stdio.h>.
      Therefore, <stdio.h> defines popen only if one or more of the
      following is true:

      -  The program including it is not compiled in strict ANSI C
         mode (/STANDARD=ANSI89).

      -  _POSIX_C_SOURCE is defined as 2 or greater.

      -  _XOPEN_SOURCE is defined.

      -  _XOPEN_SOURCE_EXTENDED is defined.

   o  The getw function is an X/Open extension to <stdio.h>.
      Therefore, <stdio.h> defines getw only if one or more of the
      following is true:

      -  The program is not compiled in strict ANSI C mode
         (/STANDARD=ANSI89).

      -  _XOPEN_SOURCE is defined.

      -  _XOPEN_SOURCE_EXTENDED is defined.

   o  The X/Open Extended symbolic constants _SC_PAGESIZE,
      _SC_PAGE_SIZE, _SC_ATEXIT_MAX, and _SC_IOV_MAX were added
      to <unistd.h> to support the sysconf function. However, these
      constants are not defined by _POSIX_C_SOURCE.

      The <unistd.h> header file defines these constants only if
      a program does not define _POSIX_C_SOURCE and does define
      _XOPEN_SOURCE_EXTENDED.

      If _POSIX_C_SOURCE is defined, these constants are not visible
      in <unistd.h>. Note that _POSIX_C_SOURCE is defined only for
      programs compiled in strict ANSI C mode.

   o  The fgetname function is a Compaq C RTL extension to
      <stdio.h>. Therefore, <stdio.h> defines fgetname only
      if the program is not compiled in strict ANSI C mode
      (/STANDARD=ANSI89).

   o  The macro _PTHREAD_KEYS_MAX is defined by POSIX 1003.1c-1995.
      This macro is made visible in <limits.h> when compiling for
      this standard with _POSIX_C_SOURCE == 199506 defined, or
      by default when compiling without any standards-defining,
      feature-test macros.

   o  The macro WCHAR_MAX defined in <wchar.h> is required by ISO C
      Amendment 1 but not by XPG4. Therefore:

      -  Compiling for ISO C Amendment 1 makes this symbol visible,
         but compiling for XPG4 compliance does not.

      -  Compiling for both ISO C Amendment 1 and XPG4 makes this
         symbol visible.

      Similarly, the functions wcsftime and wcstok in <wchar.h>
      are defined slightly differently by the ISO C Amendment 1 and
      XPG4:

      -  Compiling for ISO C Amendment 1 makes the ISO C Amendment 1
         prototypes visible.

      -  Compiling for XPG4 compliance makes the XPG4 prototypes
         visible.

      -  Compiling for both ISO C Amendment 1 and XPG4 selects the
         ISO C prototypes because conflicts resulting from this mode
         of compilation resolve in favor of ISO C.

      -  Compiling without any standard selecting feature test
         macros makes ISO C Amendment 1 features visible.

      In this example, compiling with no standard-selecting
      feature-test macros makes WCHAR_MAX and the ISO C Amendment 1
      prototypes for wcsftime and wcstok visible.

   o  The wcswidth and wcwidth functions are XPG4 extensions to
      ISO C Amendment 1. Their prototypes are in <wchar.h>.

      These symbols are visible if:

      -  Compiling for XPG4 compliance by defining _XOPEN_SOURCE or
         _XOPEN_SOURCE_EXTENDED.

      -  Compiling for DEC C Version 4.0 compatibility or on pre-
         OpenVMS Version 7.0 systems.

      -  Compiling with no standard-selecting feature-test macros.

      -  Compiling for both ISO C Amendment 1 and XPG4 compilance
         because these symbols are XPG4 extensions to ISO C
         Amendment 1.

      Compiling for strict ISO C Amendment 1 does not make them
      visible.
 

3  Multiple-Version-Support_Macro
   By default, the header files enable APIs in the Compaq C RTL
   provided by the version of the operating system on which the
   compilation occurs. This is accomplished by the predefined
   setting of the __VMS_VER macro, as described in the Compaq C
   User's Guide for OpenVMS Systems. For example, compiling on
   OpenVMS Version 6.2 causes only Compaq C RTL APIs from Version
   6.2 and earlier to be made available.

   Another example of the use of the __VMS_VER macro is support
   for the 64-bit versions of Compaq C RTL functions available
   with OpenVMS Alpha Version 7.0 and higher. In all header files,
   functions that provide 64-bit support are conditionalized so that
   they are visible only if __VMS_VER indicates a version of OpenVMS
   that is greater than or equal to 7.0.

   To target an older version of the operating system, do the
   following:

   1. Define a logical DECC$SHR to point to the old version of
      DECC$SHR. The compiler uses a table from DECC$SHR to perform
      routine name prefixing.

   2. Define __VMS_VER appropriately, either with the /DEFINE
      qualifier or with a combination of the #undef and #define
      preprocessor directives. With /DEFINE, you may need to disable
      the warning regarding redefinition of a predefined macro.

   Targeting a newer version of the operating system might not
   always be possible. For some versions, you can expect that the
   new DECC$SHR.EXE will require new features of the operating
   system that are not present. For such versions, the defining
   if the logical DECC$SHR in Step 1 would cause the compilation to
   fail.

   To override the value of __VMS_VER, define __VMS_VER_OVERRIDE  on
   the compiler command line. Defining __VMS_VER_OVERRIDE without a
   value sets __VMS_VER to the maximum value.
 

3  Compatibility_Modes
   The following predefined macros are used to select header-file
   compatibility with previous versions of DEC C) or the OpenVMS
   operating system:

   o  _DECC_V4_SOURCE

   o  _VMS_V6_SOURCE

   There are two types of incompatibilities that can be controlled
   in the header files:

   o  To conform to standards, some changes are source-code
      incompatible but binary compatible. To select DEC C Version
      4.0 source compatibility, use the _DECC_V4_SOURCE macro.

   o  Other changes to conform to standards introduce a binary or
      run-time incompatibility.

      In general, programs that recompile get new behaviors. In
      these cases, use the _VMS_V6_SOURCE feature test macro to
      retain previous behaviors.

      However, for the exit, kill, and wait functions, the OpenVMS
      Version 7.0 changes to make these routines ISO POSIX-1
      compliant were considered too incompatible to become the
      default. Therefore, in these cases the default behavior is
      the same as on pre-OpenVMS Version 7.0 systems. To access the
      versions of these routines that comply with ISO POSIX-1, use
      the _POSIX_EXIT feature test macro.

   The following examples help clarify the use of these macros:

   o  To conform to the ISO POSIX-1 standard, typedefs for the
      following have been added to <types.h>:

         dev_t         off_t
         gid_t         pid_t
         ino_t         size_t
         mode_t        ssize_t
         nlink_t       uid_t

      Previous development environments using a version of DEC C
      earlier than Version 5.2 may have compensated for the lack
      of these typedefs in <types.h> by adding them to another
      module. If this is the case on your system, then compiling
      with the <types.h> provided with DEC C Version 5.2 might cause
      compilation errors.

      To maintain your current environment and include the DEC C
      Version 5.2 <types.h>, compile with _DECC_V4_SOURCE defined.
      This will omit incompatible references from the DEC C Version
      5.2 headers. In <types.h>, for example, the previously listed
      typedefs will not be visible.

   o  As of OpenVMS Version 7.0, the Compaq C RTL getuid and
      geteuid functions are defined to return an OpenVMS UIC (user
      identification code) that contains both the group and member
      portions of the UIC. In previous versions of the DEC C RTL,
      these functions returned only the member number from the UIC
      code.

      Note that the prototypes for getuid and geteuid in <unistd.h>
      (as required by the ISO POSIX-1 standard) and in <unixlib.h>
      (for Compaq C RTL compatibility) have not changed. By default,
      newly compiled programs that call getuid and geteuid get
      the new definitions. That is, these functions will return
      an OpenVMS UIC.

      To let programs retain the pre-OpenVMS Version 7.0 behavior of
      getuid and geteuid, compile with the _VMS_V6_SOURCE feature-
      test macro defined.

   o  As of OpenVMS Version 7.0, the Compaq C RTL exit function is
      defined with ISO POSIX-1 semantics. As a result, the input
      status argument to exit takes a number between 0 and 255.
      (Prior to this, exit could take an OpenVMS condition code in
      its status parameter.)

      By default, the behavior for exit on OpenVMS systems is the
      same as before: exit accepts an OpenVMS condition code. To
      enable the ISO POSIX-1 compatible exit function, compile with
      the _POSIX_EXIT feature-test macro defined.
 

3  Curses_and_Socket_Compatibility_Macros
   The following feature-test macros are used to control the Curses
   and Socket subsets of the Compaq C RTL library:

   o  _BSD44_CURSES

      This macro selects the Curses package from the 4.4BSD Berkeley
      Software Distribution.

   o  _VMS_CURSES

      This macro selects a Curses package based on the VAX C
      compiler. This is the default Curses package.

   o  _SOCKADDR_LEN

      This macro is used to select 4.4BSD-compatible and XPG4 V2-
      compatible socket interfaces. These interfaces require support
      in your underlying TCP/IP software. Contact your TCP/IP vendor
      to inquire if the version of TCP/IP software you run supports
      4.4BSD sockets.

   Strict XPG4 V2 compliance requires the 4.4BSD-compatible socket
   interface. Therefore, if _XOPEN_SOURCE_EXTENDED is defined on
   OpenVMS Version 7.0 or higher, _SOCKADDR_LEN is defined to be 1.

   The following examples help clarify the use of these macros:

   o  Symbolic constants like AE, AL, AS, AM, BC, which represent
      pointers to termcap fields used by the BSD Curses package, are
      only visible in <curses.h> if _BSD44_CURSES is defined.

   o  The <socket.h> header file defines a 4.4BSD sockaddr structure
      only if _SOCKADDR_LEN or _XOPEN_SOURCE_EXTENDED is defined.
      Otherwise, <socket.h> defines a pre-4.4BSD sockaddr structure.
      If _SOCKADDR_LEN is defined and _XOPEN_SOURCE_EXTENDED is not
      defined,

      The <socket.h> header file also defines an osockaddr
      structure, which is a 4.3BSD sockaddr structure to be used
      for compatibility purposes. Since XPG4 V2 does not define
      an osockaddr structure, it is not visible in _XOPEN_SOURCE_
      EXTENDED mode.
 

3  2_GB_File_Size_Macro
   The C RTL provides support for compiling applications to use file
   sizes and offsets that are 2 GB and larger. This is accomplished
   by allowing file offsets of 64-bit integers.

   The fseeko and ftello functions, which have the same behavior
   as fseek and ftell, accept or return values of type off_t, which
   allows for a 64-bit variant of off_t to be used.

   C RTL functions lseek, mmap, ftuncate, truncate, stat, fstat, and
   ftw can also accommodate a 64-bit file offset.

   The new 64-bit interfaces can be selected at compile time by
   defining the _LARGEFILE feature macro.
 

3  32-Bit_UID_and_GID_Macro_(Integrity_servers,_Alpha)_
   The C RTL supports 32-bit User Identification (UID) and Group
   Identification (GID). When an application is compiled to use
   32-bit UID/GID, the UID and GID are derived from the UIC as in
   previous versions of the operating system.

   To compile an application for 16-bit UID/GID support on systems
   that by default use 32-bit UIDs/GIDs, define the _DECC_SHORT_GID_
   T macro to 1.

   Not specifying _DECC_SHORT_GID_T provides long (32-bit) UID/GID.

   Compiling on older OpenVMS systems where long UID/GID is not
   supported, or compiling for legacy compatibility (_DECC_V4_SOURCE
   for HP C Version 4 or _VMS_V6_SOURCE for OpenVMS Version 6),
   forces use of short (16-bit) UID/GID.
 

3  Standard-Compliant_stat_Structure_(Integrity_servers,_Alpha)_
   The C RTL supports an X/Open standard-compliant definition of
   the stat structure and associated definitions. To use these new
   definitions, applications must compile with the _USE_STD_STAT
   feature-test macro defined. Use of _USE_STD_STAT specifies long
   (32-bit) GIDs.

   When compiled with _USE_STD_STAT, the stat structure includes
   these changes:

   o  Type ino_t is defined as an unsigned quadword int. Without _
      USE_STD_STAT, it is an unsigned short.

   o  Type dev_t is defined as a 64-bit integer. Without _USE_STD_
      STAT, it is a 32-bit character pointer.

   o  Type off_t is defined as a 64-bit integer, as if the _
      LARGEFILE macro has been defined. Without _USE_STD_STAT, off_t
      is a 32-bit integer.

   o  Fields st_dev and st_rdev will have unique values per device.
      Without _USE_STD_STAT, uniqueness is not assured.

   o  Fields st_blksize and st_blocks are added. Without _USE_STD_
      STAT, these fields do not exist.
 

3  Using_Legacy__toupper_and__tolower_Behavior_(Integrity_servers,_Alpha)_
   As of OpenVMS Version 8.3, to comply with the C99 ANSI standard
   and X/Open Specification, the _tolower and _toupper macros by
   default do not evaluate their parameter more than once. They
   simply call their respective tolower or toupper function. This
   avoids side effects (such as i++ or function calls) where the
   user can tell how many times an expression is evaluated.

   To retain the older, optimized behavior of the _tolower and _
   toupper macros, compile with /DEFINE=_FAST_TOUPPER. Then, as
   in previous releases, these macros optimize the call to avoid
   the overhead of a runtime call. However, the macro's parameter
   is evaluated more than once to determine how to calculate the
   result, possibly creating unwanted side effects.
 

3  Using_Faster,_Inlined_Put_and_Get_Functions_(Integrity_servers,_Alpha)_
   Compiling with the __UNIX_PUTC macro defined enables an
   optimization that sets the following I/O functions to use faster,
   inlined functions:

   fgetc
   fputc
   putc
   putchar
   fgetc_unlocked
   fputc_unlocked
   putc_unlocked
   putchar_unlocked
 

3  POSIX_Style_exit_(Integrity_servers,_Alpha)_
   The HP C and C++ Version 7.1 and higher compilers have a
   /MAIN=POSIX_EXIT qualifier that defines the _POSIX_EXIT macro
   and causes the main program to call __posix_exit instead of exit
   when returning from the main program.

   This qualifier should be used with programs ported from UNIX that
   do not explicitly call exit and do not use OpenVMS specific exit
   codes.

   For older compilers, the following sample code can be used to
   force the existing main module to have a different name so that a
   simple main program will call it but force the exit status to be
   through the __posix_exit call.

   The replacement main function can be in a different module, so
   that /DEFINE="main=real_main" is all that is needed for modifying
   the build of the existing main function.

   #define _POSIX_EXIT 1

   #include <stdlib.h>

   int real_main(int argc, char **argv);

   /* Make sure POSIXized exit is used */
   int main(int argc, char **argv)
   {
   int ret_status;

      ret_status = real_main(argc, argv);

   exit (ret_status);
   }
   #define main real_main

   Unless your C program is intentionally using OpenVMS status codes
   for exit values, it is strongly recommended that both the _POSIX_
   EXIT macro be defined and, if needed, the /MAIN=POSIX_EXIT or the
   alternative main replacement be used so that DCL, BASH, and the
   accounting file get usable exit values.
 

2  Feature_Logical_Names
   The C RTL provides an extensive list of feature switches that
   can be set using DECC$ logical names. These switches affect the
   behavior of a C application at run time.

   The feature switches introduce new behaviors and also preserve
   old behaviors that have been deprecated.

   You enable most features by setting a logical name to ENABLE and
   disable a feature by setting the logical name to DISABLE:

   $ DEFINE DECC$feature ENABLE

   $ DEFINE DECC$feature DISABLE

   Some feature logical names can be set to a numeric value. For
   example:

   $ DEFINE DECC$PIPE_BUFFER_SIZE 32768

                                 NOTES

      o  Do not set C RTL feature logical names for the system.
         Set them only for the applications that need them,
         because other applications including OpenVMS components
         depend on the default behavior of these logical names.

      o  Older feature logicals from earlier releases of the
         C Run-Time Library were documented as supplying "any
         equivalence string" to enable a feature. While this was
         true at one time, we now strongly recommend that you use
         ENABLE for setting these feature logicals and DISABLE for
         disabling them. Failure to do so may produce unexpected
         results.

         The reason for this is twofold:

         -  In previous versions of the C RTL, any equivalence
            string, even DISABLE, may have enabled a feature
            logical.

         -  In subsequent and current versions of the C RTL, the
            following equivalence strings will disable a feature
            logical. Do not use them to enable a feature logical.

               DISABLE
               0 (zero)
               F
               FALSE
               N
               NO

            Any other string not on this list will enable a
            feature logical. The unintentionally misspelled string
            "DSABLE", for example, will enable a feature logical.

   The C RTL also provides several functions to manage feature
   logicals within your applications:

   decc$feature_get
   decc$feature_get_value
   decc$feature_get_index
   decc$feature_get_name
   decc$feature_set
   decc$feature_set_value
   decc$feature_show
   decc$feature_show_all

   See the reference section for more information on these
   functions.

   The C RTL feature logical names are listed below, grouped by the
   type of features they control:

      Feature Logical Name               Default
      ------- ------- ----               -------

      Performance Optimizations:

         DECC$ENABLE_GETENV_CACHE        DISABLE
         DECC$LOCALE_CACHE_SIZE          0
         DECC$TZ_CACHE_SIZE              2

      Legacy Behaviors:

         DECC$ALLOW_UNPRIVILEGED_NICE    DISABLE
         DECC$NO_ROOTED_SEARCH_LISTS     DISABLE
         DECC$PRINTF_USES_VAX_ROUND      DISABLE
         DECC$THREAD_DATA_AST_SAFE       DISABLE
         DECC$V62_RECORD_GENERATION      DISABLE
         DECC$WRITE_SHORT_RECORDS        DISABLE
         DECC$XPG4_STRPTIME              DISABLE

      File Attributes:

         DECC$DEFAULT_LRL                32767
         DECC$DEFAULT_UDF_RECORD         DISABLE
         DECC$FIXED_LENGTH_SEEK_TO_EOF   DISABLE
         DECC$ACL_ACCESS_CHECK           DISABLE

      Mailboxes:

         DECC$MAILBOX_CTX_STM            DISABLE

      Changes for UNIX Conformance:

         DECC$SELECT_IGNORES_INVALID_FD  DISABLE
         DECC$STRTOL_ERANGE              DISABLE
         DECC$VALIDATE_SIGNAL_IN_KILL    DISABLE

      General UNIX Enhancements:

         DECC$UNIX_LEVEL                 DISABLE
         DECC$ARGV_PARSE_STYLE           DISABLE
         DECC$PIPE_BUFFER_SIZE           512
         DECC$PIPE_BUFFER_QUOTA          512
         DECC$STREAM_PIPE                DISABLE
         DECC$POPEN_NO_CRLF_REC_ATTR     DISABLE
         DECC$STDIO_CTX_EOL              DISABLE
         DECC$USE_RAB64                  DISABLE
         DECC$GLOB_UNIX_STYLE            DISABLE

      Enhancements for UNIX Style Filenames:

         DECC$DISABLE_TO_VMS_LOGNAME_TRANSLATION  DISABLE
         DECC$EFS_CHARSET                  DISABLE
         DECC$ENABLE_TO_VMS_LOGNAME_CACHE  ENABLE
         DECC$FILENAME_ENCODING_UTF8       DISABLE
         DECC$FILENAME_UNIX_NO_VERSION     DISABLE
         DECC$FILENAME_UNIX_REPORT         DISABLE
         DECC$READDIR_DROPDOTNOTYPE        DISABLE
         DECC$RENAME_NO_INHERIT            DISABLE
         DECC$RENAME_ALLOW_DIR             DISABLE

      Enhancements for UNIX Style File Attributes:

         DECC$EFS_FILE_TIMESTAMPS        DISABLE
         DECC$EXEC_FILEATTR_INHERITANCE  DISABLE
         DECC$FILE_OWNER_UNIX            DISABLE
         DECC$FILE_PERMISSION_UNIX       DISABLE
         DECC$FILE_SHARING               DISABLE

      UNIX Compliance Mode:

         DECC$DETACHED_CHILD_PROCESS     DISABLE
         DECC$FILENAME_UNIX_ONLY         DISABLE
         DECC$POSIX_STYLE_UID            DISABLE
         DECC$USE_JPI$_CREATOR           DISABLE

      New Behaviors for POSIX Conformance:

         DECC$ALLOW_REMOVE_OPEN_FILES    DISABLE
         DECC$POSIX_SEEK_STREAM_FILE     DISABLE
         DECC$UMASK                      RMS default

      Filename Handling:

         DECC$POSIX_COMPLIANT_PATHNAMES  DISABLE

         DECC$DISABLE_POSIX_ROOT         ENABLE
         DECC$EFS_CASE_PRESERVE          DISABLE
         DECC$EFS_CASE_SPECIAL           DISABLE
         DECC$EFS_NO_DOTS_IN_DIRNAME     DISABLE
         DECC$READDIR_KEEPDOTDIR         DISABLE
         DECC$UNIX_PATH_BEFORE_LOGNAME   DISABLE
 

3  DECC$ACL_ACCESS_CHECK
   The DECC$ACL_ACCESS_CHECK feature logical controls the behavior
   of the access function.

   With DECC$ACL_ACCESS_CHECK enabled, the access function checks
   both UIC protection and OpenVMS Access Control Lists (ACLs).

   With DECC$ACL_ACCESS_CHECK disabled, the access function checks
   only UIC protection.
 

3  DECC$ALLOW_REMOVE_OPEN_FILES
   The DECC$ALLOW_REMOVE_OPEN_FILES feature logical controls the
   behavior of the remove function on open files. Ordinarily, the
   operation fails. However, POSIX conformance dictates that the
   operation succeed.

   With DECC$ALLOW_REMOVE_OPEN_FILES enabled, this POSIX conformant
   behavior is achieved.
 

3  DECC$ALLOW_UNPRIVILEGED_NICE
   With DECC$ALLOW_UNPRIVILEGED_NICE enabled, the nice function
   exhibits its legacy behavior of not checking the privilege of
   the calling process (that is, any user may lower the nice value
   to increase process priorities). Also, when the caller sets a
   priority above MAX_PRIORITY, the nice value is set to the base
   priority.

   With DECC$ALLOW_UNPRIVILEGED_NICE disabled, the nice function
   conforms to the X/Open standard of checking the privilege of the
   calling process (only users with ALTPRI privilege can lower the
   nice value to increase process priorities), and when the caller
   sets a priority above MAX_PRIORITY, the nice value is set to MAX_
   PRIORITY.
 

3  DECC$ARGV_PARSE_STYLE
   With DECC$ARGV_PARSE_STYLE enabled, case is preserved in command-
   line arguments when the process has been set up for extended DCL
   parsing using SET PROCESS/PARSE_STYLE=EXTENDED.

   DECC$ARGV_PARSE_STYLE must be defined externally as a logical
   name or set in a function called using the LIB$INITIALIZE
   mechanism because it is evaluated before function main is
   called.
 

3  DECC$DEFAULT_LRL
   DECC$DEFAULT_LRL specifies the default value for the RMS
   attribute for the longest record length. The default value 32767
   is the largest record size supported by RMS.

   Default: 32767

   Maximum: 32767
 

3  DECC$DEFAULT_UDF_RECORD
   With DECC$DEFAULT_UDF_RECORD enabled, file access mode defaults
   to RECORD instead of STREAM mode for all files except STREAMLF.
 

3  DECC$DETACHED_CHILD_PROCESS
   With DECC$DETACHED_CHILD_PROCESS enabled, child processes created
   using vfork and exec are created as detached processes instead of
   subprocesses.

   This feature has only limited support. In some cases the console
   cannot be shared between the parent process and the detached
   process, which can cause exec to fail.
 

3  DECC$DISABLE_POSIX_ROOT
   With DECC$DISABLE_POSIX_ROOT enabled, support for the POSIX root
   directory defined by SYS$POSIX_ROOT is disabled.

   With DECC$DISABLE_POSIX_ROOT disabled, the SYS$POSIX_ROOT logical
   name is interpreted as the equivalent of the file path "/". If
   a UNIX path starting with a slash (/)  is given and the value
   after the leading slash cannot be translated as a logical name,
   SYS$POSIX_ROOT is used as the parent directory for the specified
   UNIX file path.

   The C RTL supports a UNIX style root that behaves like a real
   directory. This allows such actions as:

   % cd /
   % mkdir /dirname
   % tar -xvf tarfile.tar /dirname
   % ls /

   Previously, the C RTL did not recognize "/" as a directory name.
   The normal processing for a file path starting with "/" was to
   interpret the first element as a logical name or device name. If
   this failed, there was special processing for the name /dev/null
   and names starting with /bin and /tmp:

   /dev/null       NLA0:
   /bin            SYS$SYSTEM:
   /tmp            SYS$SCRATCH:

   These behaviors are retained for compatibility purposes. In
   addition, support has been added to the C RTL for the logical
   name SYS$POSIX_ROOT as an equivalent to "/".

   To enable this feature for use by the C RTL, define SYS$POSIX_
   ROOT as a concealed logical name. For example:

   $ DEFINE/TRANSLATION=(CONCEALED,TERMINAL) SYS$POSIX_ROOT -
                                       "$1$DKA0:[SYS0.abc.]"

   To disable this feature:

   $ DEFINE DECC$DISABLE_POSIX_ROOT DISABLE

   Enabling SYS$POSIX_ROOT results in the following behavior:

   o  If the existing translation of a UNIX path starting with "/"
      fails and SYS$POSIX_ROOT is defined, the name is interpreted
      as if it starts with /sys$posix_root.

   o  When converting from an OpenVMS to a UNIX style filename,
      and the OpenVMS name starts with "SYS$POSIX_ROOT:", then
      the "SYS$POSIX_ROOT:" is removed. For example, SYS$POSIX_
      ROOT:[dirname] becomes /dirname. If the resulting name
      could be interpreted as a logical name or one of the special
      cases previously listed, the result is /./dirname instead of
      /dirname.
 

3  DECC$DISABLE_TO_VMS_LOGNAME_TRANSLATION
   With DECC$DISABLE_TO_VMS_LOGNAME_TRANSLATION enabled, the
   conversion routine decc$to_vms will only treat the first element
   of a UNIX style name as a logical name if there is a leading
   slash (/).
 

3  DECC$EFS_CASE_PRESERVE
   With DECC$EFS_CASE_PRESERVE enabled, case is preserved for
   filenames on ODS-5 disks.

   With DECC$EFS_CASE_PRESERVE disabled, UNIX style filenames are
   always reported in lowercase.

   However, note that enabling DECC$EFS_CASE_SPECIAL overrides the
   setting for DECC$EFS_CASE_PRESERVE.
 

3  DECC$EFS_CASE_SPECIAL
   With DECC$EFS_CASE_SPECIAL enabled, case is preserved only for
   filenames containing lowercase. If an element of a filename
   contains all uppercase letters, it is reported in all lowercase
   in UNIX style.

   When enabled, DECC$EFS_CASE_SPECIAL overrides the value of
   DECC$EFS_CASE_PRESERVE.
 

3  DECC$EFS_CHARSET
   With DECC$EFS_CHARSET enabled, UNIX names can contain ODS-5
   extended characters. Support includes multiple dots and all ASCII
   characters in the range 0 to 255, except the following:

   <NUL>
   /         *
   "         ?

   Unless DECC$FILENAME_UNIX_ONLY is enabled, some characters can be
   interpreted as OpenVMS characters depending on context. They are:

   :         ^
   [         ;
   <

   DECC$EFS_CHARSET might be necessary for existing applications
   that make assumptions about filenames based on the presence
   of certain characters, because the following nonstandard and
   undocumented C RTL extensions do not work when EFS extended
   character-set support is enabled:

   o  $HOME is interpreted as the user's login directory

      With DECC$EFS_CHARSET enabled, $HOME is treated literally and
      may be in an OpenVMS or UNIX style filename.

   o  ~name is interpreted as the login directory for user name

      With DECC$EFS_CHARSET enabled, ~name is treated literally and
      can be in an OpenVMS or UNIX style filename.

   o  Wild card regular expressions in the form [a-z]

      With DECC$EFS_CHARSET enabled, square brackets are acceptable
      in OpenVMS and UNIX style filenames. For instance, in a
      function such as open, abc[a-z]ef.txt is interpreted as a
      UNIX style name equivalent to the OpenVMS style name abc^[a-
      z^]ef.txt, and [a-z]bc is interpreted as an OpenVMS style name
      equivalent to the UNIX style name /sys$disk/a-z/bc.

   With DECC$EFS_CHARSET enabled, the following encoding for EFS
   extended characters is supported when converting from an OpenVMS
   style filename to a UNIX style filename:

   o  All ODS-2 compatible names

   o  All encoding for 8-bit characters, either as single byte or
      using two-digit hexadecimal form ^ab. In a UNIX path these are
      always represented as a single byte.

   o  Encoding for DEL (^7F)

   o  The following characters when preceded by a caret:

      space ! , _ & ' ( ) + @ { } ; # [ ] % ^ = $ - ~ .

   o  The following characters when not preceded by a caret:

      $  -  ~  .

   o  The implementation supports the conversion from OpenVMS to
      UNIX needed for functions readdir, ftw, getname, fgetname,
      getcwd, and others.

                                  NOTE

      There are some special cases in C RTL filename processing.
      For example:

      o  Pathnames ending in ^.dir are treated as directories, and
         when translated, these characters are truncated from the
         string.

      o  Pathnames begining with ^/ treat the next token as a
         logical name or a directory from the root.

      The following sample program shows these nuances:

      #include <stdio.h>
      #include <dirent.h>
      #include <unixlib.h>
      #include <string.h>
      main()
      {
        char adir[80];
        DIR *dir;
        struct dirent *dp;
        int decc_feature_efs_charset_index = 0;
        int decc_feature_efs_charset_default_val = 0;

        if (
            ( (decc_feature_efs_charset_index =
              decc$feature_get_index("DECC$EFS_CHARSET")) == -1 )
            ||
            ( (decc_feature_efs_charset_default_val =
  decc$feature_get_value(decc_feature_efs_charset_index, 0)) == -1 )
            ||
( (decc$feature_set_value(decc_feature_efs_charset_index, 1, TRUE) == -1))
           )
          {
            printf("Error setting up DECC$EFS_CHARSET macro\n");
          }

        strcpy(adir, "SYS$SYSDEVICE:[SSHTEST.TEST.a^,test^.dir^;22]");
        printf("\n\nFor %s\n", adir);
      mrb:  dir = opendir(adir);
        if(dir)
          {
            do
              {
                dp = readdir(dir);
                if(dp->d_name) printf("%s\n", dp->d_name);
              } while (dp);
          }

        closedir(dir);

        strcpy(adir, "SYS$SYSDEVICE:[SSHTEST.TEST.a^,test^.dir]");
        printf("\n\nFor %s\n", adir);
        dir = opendir(adir);
        if(dir)
          {
            do
              {
                dp = readdir(dir);
                if(dp->d_name) printf("%s\n", dp->d_name);
              } while (dp);
          }

        closedir(dir);

        strcpy(adir, "SYS$SYSDEVICE:[SSHTEST.TEST.a^\\test]");
        printf("\n\nFor %s\n", adir);
        dir = opendir(adir);
        if(dir)
          {
            do
              {
                dp = readdir(dir);
                if(dp->d_name) printf("%s\n", dp->d_name);
              } while (dp);
          }

        strcpy(adir, "SYS$SYSDEVICE:[SSHTEST.TEST.copies]");
        printf("\n\nFor %s\n", adir);
        dir = opendir(adir);
        if(dir)
          {
            do
              {
                dp = readdir(dir);
                if(dp->d_name) printf("%s\n", dp->d_name);
              } while (dp);
          }

        closedir(dir);

        strcpy(adir, "/SYS$SYSDEVICE/SSHTEST/TEST/copies");
        printf("\n\nFor %s\n", adir);
        dir = opendir(adir);
        if(dir)
          {
            do
              {
                dp = readdir(dir);
                if(dp->d_name) printf("%s\n", dp->d_name);
              } while (dp);
          }

        closedir(dir);

      }
 

3  DECC$EFS_FILE_TIMESTAMPS
   With DECC$EFS_FILE_TIMESTAMPS enabled, stat and fstat report
   new ODS-5 access time (st_atime), attribute revision time 
   (st_ctime) and modification time (st_mtime) for files on ODS-5
   volumes that have the extended file times enabled using SET
   VOLUME/VOLUME=ACCESS_DATES.

   If DECC$EFS_FILE_TIMESTAMPS is disabled, or the volume is not
   ODS-5, or the volume does not have support for these additional
   times enabled, st_ctime continues to be the file creation time
   and st_atime the same as the st_mtime.

   The utime and utimes functions support these ODS-5 times in the
   same way as stat.
 

3  DECC$EFS_NO_DOTS_IN_DIRNAME
   With support for extended characters in filenames for ODS-5,
   a name such as NAME.EXT can be interpreted as NAME.EXT.DIR.
   Determining if directory [.name^.ext] exists adds overhead to
   UNIX name translation when support for extended character support
   in UNIX filenames is enabled.

   Enabling the DECC$EFS_NO_DOTS_IN_DIRNAME feature logical
   suppresses the interpretation of a filename containing dots as
   a directory name. With this logical enabled, NAME.EXT is assumed
   to be a filename; no check is made for directory [.name^.ext].
 

3  DECC$ENABLE_GETENV_CACHE
   The C RTL supplements the list of environment variables in the
   environ table with all logical names and DCL symbols available to
   the process.

   By default, whenever getenv is called for a name not in the
   environ table, an attempt is made to resolve this as a logical
   name and, if this fails, as a DCL symbol.

   With DECC$ENABLE_GETENV_CACHE enabled, once a logical name or
   DCL name has been successfully translated, its value is stored
   in a cache. When the same name is requested in a future call
   to getenv, the value is returned from the cache instead of
   reevaluating the logical name or DCL symbol.
 

3  DECC$ENABLE_TO_VMS_LOGNAME_CACHE
   Use the DECC$ENABLE_TO_VMS_LOGNAME_CACHE to improve the
   performance of UNIX name translation. The value is the life of
   each cache entry in seconds. The equivalence string ENABLE is
   evaluated as 1 second.

   Define DECC$ENABLE_TO_VMS_LOGNAME_CACHE to 1 to enable the cache
   with a 1-second life for each entry.

   Define DECC$ENABLE_TO_VMS_LOGNAME_CACHE to 2 to enable the cache
   with a 2-second life for each entry.

   Define DECC$ENABLE_TO_VMS_LOGNAME_CACHE to -1 to enable the cache
   without a cache entry expiration.
 

3  DECC$EXEC_FILEATTR_INHERITANCE
   The DECC$EXEC_FILEATTR_INHERITANCE feature logical affects child
   processes that are C programs.

   For versions of OpenVMS before Version 7.3-2, DECC$EXEC_FILEATTR_
   INHERITANCE is either enabled or disabled:

   o  With DECC$EXEC_FILEATTR_INHERITANCE enabled, the current file
      pointer and the file open mode is passed to the child process
      in exec calls.

   o  With this logical name disabled, the child process does not
      inherit append mode or the file position.

   For OpenVMS Version 7.3-2 and higher, DECC$EXEC_FILEATTR_
   INHERITANCE can be defined to 1 or 2, or be disabled:

   o  With DECC$EXEC_FILEATTR_INHERITANCE defined to 1, a child
      process inherits file positioning for all file access modes
      except append.

   o  With DECC$EXEC_FILEATTR_INHERITANCE defined to 2, a child
      process inherits file positioning for all file access modes
      including append.

   o  With DECC$EXEC_FILEATTR_INHERITANCE disabled, a child process
      does not inherit the file position for any access modes.
 

3  DECC$FILENAME_ENCODING_UTF8
   C RTL routines that deal with filenames now support filenames in
   UTF-8 encoding when given in UNIX style.

   For example, on an ODS-5 disk the OpenVMS DIRECTORY command
   supports a filename with the following characters:

   disk:[mydir]^U65E5^U672C^U8A9E.txt

   This filename contains three UCS-2 characters (call them xxx,
   yyy, and zzz for typographical purposes) meaning "day", "origin",
   and "language", respectively.

   With UTF-8 support enabled, a C program can now read the filename
   from the VMS directory and use that filename as an UTF-8 encoded
   string.

   For example, opendir("/disk/mydir") followed by a readdir will
   place the following into the d_name field of the supplied dirent
   structure:

   "\xE6\x97\xA5\xE6\x9C\xAC\xE8\xAA\x9E.txt"

   One of the following calls can then open this file:

   open("/disk/mydir/\xE6\x97\xA5\xE6\x9C\xAC\xE8\xAA\x9E.txt",O_RDWR,0)
   open("/disk/mydir/xxxyyyzzz.txt", O_RDWR,0)

   The "\xE6\x97\xA5" above is the byte stream E697A5, which
   represents the xxx character in UTF-8 encoding. 

   This feature enhances the UNIX portability of international
   software that uses UTF-8 encoded filenames.

   The DECC$FILENAME_ENCODING_UTF8 feature logical controls whether
   or not the C RTL allows and correctly interprets Unicode UTF-8
   encoding for filenames given in UNIX style.

   This logical is undefined by default, and the C RTL behavior is
   to accept filenames as ASCII and Latin-1 format.

   This feature works only on ODS-5 disks. Therefore, to enable
   Unicode UTF-8 encoding, you must define both the DECC$FILENAME_
   ENCODING_UTF8 and DECC$EFS_CHARSET logicals to ENABLE.
 

3  DECC$FILENAME_UNIX_ONLY
   With DECC$FILENAME_UNIX_ONLY enabled, filenames are never
   interpreted as OpenVMS style names. This prevents any
   interpretation of the following as OpenVMS special characters:

   :   [   ^
 

3  DECC$FILENAME_UNIX_NO_VERSION
   With DECC$FILENAME_UNIX_NO_VERSION enabled, OpenVMS version
   numbers are not supported in UNIX style filenames.

   With DECC$FILENAME_UNIX_NO_VERSION disabled, in UNIX style names,
   version numbers are reported preceded by a period (.).
 

3  DECC$FILENAME_UNIX_REPORT
   With DECC$FILENAME_UNIX_REPORT enabled, all filenames are
   reported in UNIX style unless the caller specifically selects
   OpenVMS style. This applies to getpwnam, getpwuid, argv[0],
   getname, fgetname, and tempnam.

   With DECC$FILENAME_UNIX_REPORT disabled, unless specified in the
   function call, filenames are reported in OpenVMS style.
 

3  DECC$FILE_PERMISSION_UNIX
   With DECC$FILE_PERMISSION_UNIX enabled, the file permissions
   for new files and directories are set according to the file
   creation mode and umask. This includes mode 0777. When an earlier
   version of the file exists, the file permissions for the new file
   are inherited from the earlier version. This mode sets DELETE
   permission for a new directory when WRITE permission is enabled.

   With DECC$FILE_PERMISSION_UNIX disabled, modes 0 and 0777
   indicate using RMS default protection or protection from the
   previous version of the file. Permissions for new directories
   also follow OpenVMS rules, including disabling DELETE
   permissions.
 

3  DECC$FILE_SHARING
   With DECC$FILE_SHARING enabled, all files are opened with full
   sharing enabled (FAB$M_DEL | FAB$M_GET | FAB$M_PUT | FAB$M_UPD).
   This is set as a logical OR with any sharing mode specified by
   the caller.
 

3  DECC$FIXED_LENGTH_SEEK_TO_EOF
   With DECC$FIXED_LENGTH_SEEK_TO_EOF enabled, lseek, fseeko, and
   fseek with the direction parameter set to SEEK_END will position
   relative to the last byte in the file for files with fixed-length
   records.

   With DECC$FIXED_LENGTH_SEEK_TO_EOF disabled, lseek, fseek, and
   fseeko when called with SEEK_EOF on files with fixed-length
   records, will position relative to the end of the last record
   in the file.
 

3  DECC$GLOB_UNIX_STYLE
   Enabling DECC$GLOB_UNIX_STYLE selects the UNIX mode of the glob
   function, which uses UNIX style filenames and wildcards instead
   of OpenVMS style filenames and wildcards.
 

3  DECC$LOCALE_CACHE_SIZE
   DECC$LOCALE_CACHE_SIZE defines how much memory, in bytes, to
   allocate for caching locale data. The default value is 0, which
   disables the locale cache.

   Default: 0

   Maximum: 2147483647
 

3  DECC$MAILBOX_CTX_STM
   By default, an open on a local mailbox that is not a pipe treats
   mailbox records as having a record attribute of FAB$M_CR.

   With DECC$MAILBOX_CTX_STM enabled, the record attribute FAB$M_CR
   is not set.
 

3  DECC$NO_ROOTED_SEARCH_LISTS
   When the decc$to_vms function evaluates a UNIX style path string,
   if it determines the first element to be a logical name, then:

   o  For rooted logicals or devices, it appends ":[000000]" to the
      logical name.

      For example, if log1 is a rooted logical ($DEFINE LOG1
      [DIR_NAME.]) then /log1/filename.ext translates to
      LOG1:[000000]FILENAME.EXT.

   o  For nonrooted logicals, it appends just a colon (:)  to the
      logical name.

      For example, if log2 is a nonrooted logical ($ DEFINE
      LOG2 [DIR_NAME]), then /log2/filename.ext translates to
      LOG2:FILENAME.EXT.

   o  If the first element is a search-list logical, the translation
      proceeds by evaluating the first element in the search list,
      and translating the path as previously described.

   The preceding three cases lead to predictable, expected results.

   In the case where the first element is a search list that
   consists of a mixture of rooted and nonrooted logicals,
   translating paths as described previously can lead to different
   behavior from that of older versions of OpenVMS (before OpenVMS
   Version 7.3-1):

   o  Before OpenVMS Version 7.3-1, regardless of the contents of
      the logical, the decc$to_vms function appended only a colon
      (:).  For search lists that consisted of a mixture of rooted
      and nonrooted logicals, this resulted in certain expected
      behaviors.

   o  For OpenVMS Version 7.3-1 and later, if the first element
      of the mixed search list is a rooted logical, then decc$to_
      vms appends ":[000000]" to the logical name, resulting in
      different behavior from that of OpenVMS releases prior to
      Version 7.3-1.

   DECC$NO_ROOTED_SEARCH_LISTS controls how the decc$to_vms function
   resolves search-list logicals and provides a means to restore the
   OpenVMS behavior prior to Version 7.3-1.

   With DECC$NO_ROOTED_SEARCH_LISTS enabled:

   o  If a logical is detected in a file specification, and it is
      a search list, then a colon (:)  is appended when forming the
      OpenVMS file specification.

   o  If it is not a search list, the behavior is the same as with
      DECC$NO_ROOTED_SEARCH_LISTS disabled.

   Enabling this feature logical provides the pre-Version 7.3-1
   behavior for search list logicals.

   With DECC$NO_ROOTED_SEARCH_LISTS disabled:

   o  If a logical is detected in a file specification, and it is
      a rooted logical (or a search list whose first element is a
      rooted logical), then ":[000000]" is appended when forming the
      OpenVMS file specification.

   o  If it is a nonrooted logical (or a search list whose first
      element is a nonrooted logical), then just a colon (:)  is
      appended.

   Disabling this feature logical provides the behavior for OpenVMS
   Version 7.3-1 and later.
 

3  DECC$PIPE_BUFFER_QUOTA
   OpenVMS Version 7.3-2 adds an optional fourth argument of type
   int to the pipe function to specify the buffer quota of the
   pipe's mailbox. In previous OpenVMS versions, the buffer quota
   was equal to the buffer size.

   DECC$PIPE_BUFFER_QUOTA lets you specify a buffer quota to use
   for the pipe function if the optional fourth argument of that
   function is omitted.

   If the optional pipe fourth argument is omitted and DECC$PIPE_
   BUFFER_QUOTA is not defined, then the buffer quota defaults to
   the buffer size, as before.

   Default: 512

   Minimum: 512

   Maximum: 2147483647
 

3  DECC$PIPE_BUFFER_SIZE
   The system default buffer size of 512 bytes for pipe write
   operations can limit performance and generate extra line feeds
   when handling messages longer than 512 bytes.

   DECC$PIPE_BUFFER_SIZE allows a larger buffer size to be used for
   pipe functions such as pipe and popen. A value of 512 to 65535
   bytes can be specified.

   If DECC$PIPE_BUFFER_SIZE is not specified, the default buffer
   size 512 is used.

   Default: 512

   Minimum: 512

   Maximum: 65535
 

3  DECC$POPEN_NO_CRLF_REC_ATTR
   With DECC$POPEN_NO_CRLF_REC_ATTR disabled, a pipe opened with the
   popen function has its record attributes set to CR/LF carriage
   control (fab$b_rat |= FAB$M_CR). This is the default behavior.

   With DECC$POPEN_NO_CRLF_REC_ATTR enabled, CR/LF carriage control
   is prevented from being added to the pipe records. This is
   compatible with UNIX behavior, but be aware that enabling this
   feature might result in undesired behavior from other functions,
   such as gets, that rely on the carriage-return character.
 

3  DECC$POSIX_COMPLIANT_PATHNAMES
   With DECC$POSIX_COMPLIANT_PATHNAMES enabled, an application
   is allowed to present POSIX-compliant pathnames to any C RTL
   function that accepts a pathname.

   By default DECC$POSIX_COMPLIANT_PATHNAMES is disabled, and the
   usual C RTL behavior prevails. This disabled mode includes
   interpretation of pathnames as UNIX style specifications and
   uses rules that are different and unrelated to POSIX-compliant
   pathname processing.

   To enable DECC$POSIX_COMPLIANT_PATHNAMES, set it to one of the
   following values:

     1 All pathnames are designated as POSIX style.
     2 Pathnames that end in ":" or contain any of the bracket
       characters "[]<>", and that can be successfully parsed by
       the SYS$FILESCAN service, are designated as OpenVMS style.
       Otherwise, they are designated as POSIX style.
     3 The pathnames "." and "..", or pathnames that contain "/" are
       designated as POSIX style. Otherwise, they are designated as
       OpenVMS style.
     4 All pathnames are designated as OpenVMS style.

   See Chapter 12 of the Compaq C Run-Time Library Reference Manual
   for OpenVMS Systems for more information on POSIX-compliant
   pathnames and symbolic links.
 

3  DECC$POSIX_SEEK_STREAM_FILE
   With DECC$POSIX_SEEK_STREAM_FILE enabled, positioning beyond
   end-of-file on STREAM files does not write to the file until the
   next write. If the write is beyond the current end-of-file, this
   positions beyond the old end-of-file, and the start position for
   the write is filled with zeros.

   With DECC$POSIX_SEEK_STREAM_FILE disabled, positioning beyond
   end-of-file will immediately write zeros to the file from the
   current end-of-file to the new position.
 

3  DECC$POSIX_STYLE_UID
   With DECC$POSIX_STYLE_UID enabled, 32-bit UIDs and GIDs are
   interpreted as POSIX style identifiers.

   With this logical name disabled, UIDs and GIDs are derived from
   the process UIC.

   This feature is only available on OpenVMS systems providing POSIX
   style UID and GID support.
 

3  DECC$PRINTF_USES_VAX_ROUND
   With DECC$PRINTF_USES_VAX_ROUND enabled, the F and E format
   specifiers of printf use VAX rounding rules for programs compiled
   with IEEE float.
 

3  DECC$READDIR_DROPDOTNOTYPE
   With DECC$READDIR_DROPDOTNOTYPE enabled, readdir when reporting
   files in UNIX style only reports the trailing period (.)  for
   files with no file type when the filename contains a period.

   With this logical name disabled, all files without a file type
   are reported with a trailing period.
 

3  DECC$READDIR_KEEPDOTDIR
   The default behavior when reporting files in UNIX style from
   readdir is to report directories without a file type.

   With DECC$READDIR_KEEPDOTDIR enabled, directories are reported in
   UNIX style with a file type of ".DIR".
 

3  DECC$RENAME_NO_INHERIT
   DECC$RENAME_NO_INHERIT provides more UNIX compliant behavior in
   the rename function. With DECC$RENAME_NO_INHERIT enabled, the
   following behaviors are enforced:

   o  If the old argument points to the pathname of a file that
      is not a directory, the new argument will not point to the
      pathname of a directory.

   o  The new argument cannot point to a directory that exists.

   o  If the old argument points to the pathname of a directory, the
      new argument will not point to the pathname of a file that is
      not a directory.

   o  The new name for the file does not inherit anything from
      the old name. The new name must be specified completely. For
      example:

      Renaming "A.A" to "B" yields "B"

   With this logical name disabled, you get the expected OpenVMS
   behavior. For example:

   Renaming "A.A" to "B" yields "B.A"
 

3  DECC$RENAME_ALLOW_DIR
   Enabling DECC$RENAME_ALLOW_DIR restores the prior OpenVMS
   behavior of the rename function by allowing conversion to a
   directory specification when the second argument is an ambiguous
   file specification passed as a logical name. The ambiguity is
   whether the logical name is a UNIX or OpenVMS file specification.
   Consider the following example with DECC$RENAME_ALLOW_DIR
   enabled:

   rename("file.ext", "logical_name") 
                           /*where logical_name = dev:[dir.subdir]*/
                           /* and :[dir.subdir] exists.          */

   This results in:

   dev:[dir.subdir]file.ext

   This example renames a file from one directory into another
   directory, which is the same behavior as in legacy versions
   of OpenVMS (versions before 7.3-1). Also in this example, if
   dev:[dir.subdir] does not exist, rename returns an error.

   Disabling DECC$RENAME_ALLOW_DIR provides a more UNIX compliant
   conversion of the "logical_name" argument of rename. Consider the
   following example with DECC$RENAME_ALLOW_DIR disabled:

   rename("file.ext", "logical_name") 
                       /* where logical_name = dev:[dir.subdir] */

   This results in:

   dev:[dir]subdir.ext

   This example renames the file using the subdir part of the
   "logical_name" argument as the new filename because on UNIX
   systems, renaming a file to a directory is not allowed. So
   rename internally converts the "logical_name" to a filename, and
   dev:[dir]subdir is the most reasonable conversion it can perform.

   This new feature switch has a side effect of causing rename to a
   directory to take precedence over rename to a file. Consider this
   example:

   rename ( "file1.ext", "dir2" )      /* dir2 is not a logical */

   With DECC$RENAME_ALLOW_DIR disabled, this example results in
   dir2.ext, regardless of whether or not subdirectory [.dir2]
   exists.

   With DECC$RENAME_ALLOW_DIR enabled, this example results in
   dir2.ext only if subdirectory [.dir2] does not exist. If
   subdirectory [.dir2] does exist, the result is [.dir2]file1.ext.

                                  NOTE

      If DECC$RENAME_NO_INHERIT is enabled, UNIX compliant
      behavior is expected, so DECC$RENAME_ALLOW_DIR is ignored,
      and renaming a file to a directory is not allowed.
 

3  DECC$SELECT_IGNORES_INVALID_FD
   With DECC$SELECT_IGNORES_INVALID_FD enabled, select fails with
   errno set to EBADF when an invalid file descriptor is specified
   in one of the descriptor sets.

   With DECC$SELECT_IGNORES_INVALID_FD disabled, select ignores
   invalid file descriptors.
 

3  DECC$STDIO_CTX_EOL
   With DECC$STDIO_CTX_EOL enabled, writing to stdout and stderr
   for stream access is deferred until a terminator is seen or the
   buffer is full.

   With DECC$STDIO_CTX_EOL disabled, each fwrite generates a
   separate write, which for mailbox and record files generates a
   separate record.
 

3  DECC$STREAM_PIPE
   With DECC$STREAM_PIPE enabled, the C RTL pipe function uses the
   more UNIX compatible stream I/O.

   With DECC$STREAM_PIPE disabled, pipe uses the OpenVMS legacy
   record I/O. This is the default.
 

3  DECC$STRTOL_ERANGE
   With DECC$STRTOL_ERANGE enabled, the strtol behavior for an
   ERANGE error is corrected to consume all remaining digits in
   the string.

   With DECC$STRTOL_ERANGE disabled, the legacy behavior of leaving
   the pointer at the failing digit is preserved.
 

3  DECC$THREAD_DATA_AST_SAFE
   The C RTL has a mode that allocates storage for thread-specific
   data allocated by threads at non-AST level separate for data
   allocated for ASTs. In this mode, each access to thread-
   specific data requires a call to LIB$AST_IN_PROG, which can add
   significant overhead when accessing thread-specific data in the
   C RTL.

   The alternate mode protects thread-specific data only if another
   function has it locked. This protects data that is in use within
   the C RTL, but does not protect the caller from an AST changing
   the data pointed to.

   This latter mode is now the C RTL default for the strtok, ecvt,
   and fcvt functions.

   You can select the legacy AST safe mode by enabling DECC$THREAD_
   DATA_AST_SAFE.
 

3  DECC$TZ_CACHE_SIZE
   DECC$TZ_CACHE_SIZE specifies the number of time zones that can be
   held in memory.

   Default: 2

   Maximum: 2147483647
 

3  DECC$UMASK
   DECC$UMASK specifies the default value for the permission mask
   umask. By default, a parent C program sets the umask from the RMS
   default permissions for the process. A child process inherits the
   parent's value for umask.

   To enter the value as an octal value, add the leading zero;
   otherwise, it is translated as a decimal value. For example:

   $ DEFINE DECC$UMASK 026

   Maximum: 0777
 

3  DECC$UNIX_LEVEL
   With the DECC$UNIX_LEVEL logical name, you can manage multiple
   C RTL feature logical names at once. By setting a value for
   DECC$UNIX_LEVEL from 1 to 100, you determine the default value
   for groups of feature logical names. The value you set has a
   cumulative effect: the higher the value, the more groups that
   are affected. Setting a value of 20, for example, enables all the
   feature logicals associated with a DECC$UNIX_LEVEL of 20, 10, and
   1.

   The principal logical names affecting UNIX like behavior are
   grouped as follows:

      1    General corrections
      10   Enhancements
      20   UNIX style filenames
      30   UNIX style file attributes
      90   Full UNIX behavior - No concessions to OpenVMS

   Level 30 is appropriate for UNIX like programs such as BASH and
   GNV.

   The DECC$UNIX_LEVEL values and associated groups of affected
   feature logical names are:

   General Corrections          (DECC$UNIX_LEVEL 1)

      DECC$FIXED_LENGTH_SEEK_TO_EOF   1
      DECC$POSIX_SEEK_STREAM_FILE     1
      DECC$SELECT_IGNORES_INVALID_FD  1
      DECC$STRTOL_ERANGE              1
      DECC$VALIDATE_SIGNAL_IN_KILL    1

   General Enhancements        (DECC$UNIX_LEVEL 10)

      DECC$ARGV_PARSE_STYLE           1
      DECC$EFS_CASE_PRESERVE          1
      DECC$STDIO_CTX_EOL              1
      DECC$PIPE_BUFFER_SIZE           4096
      DECC$USE_RAB64                  1

   UNIX style filenames       (DECC$UNIX_LEVEL 20)

      DECC$DISABLE_TO_VMS_LOGNAME_TRANSLATION 1
      DECC$EFS_CHARSET                1
      DECC$FILENAME_UNIX_NO_VERSION   1
      DECC$FILENAME_UNIX_REPORT       1
      DECC$READDIR_DROPDOTNOTYPE      1
      DECC$RENAME_NO_INHERIT          1
      DECC$GLOB_UNIX_STYLE

   UNIX like file attributes     (DECC$UNIX_LEVEL 30)

      DECC$EFS_FILE_TIMESTAMPS        1
      DECC$EXEC_FILEATTR_INHERITANCE  1
      DECC$FILE_OWNER_UNIX            1
      DECC$FILE_PERMISSION_UNIX       1
      DECC$FILE_SHARING               1

   UNIX compliant behavior       (DECC$UNIX_LEVEL 90)

      DECC$FILENAME_UNIX_ONLY         1
      DECC$POSIX_STYLE_UID            1
      DECC$USE_JPI$_CREATOR           1
      DECC$DETACHED_CHILD_PROCESS     1

                                 NOTES

      o  Defining a logical name for an individual feature logical
         supersedes the default value established by DECC$UNIX_
         LEVEL for that feature.

      o  Future revisions of the C RTL may add new feature
         logicals to a given DECC$UNIX_LEVEL. For applications
         that specify that UNIX level, the effect is to enable
         those new feature logicals by default.
 

3  DECC$UNIX_PATH_BEFORE_LOGNAME
   With DECC$UNIX_PATH_BEFORE_LOGNAME enabled, when translating
   a UNIX filename not starting with a leading slash (/), an
   attempt is made to match this to a file or directory in the
   current directory. If this is not found and the name is valid
   as a logical name in an OpenVMS filename, an attempt is made to
   translate the logical name and, if found, is used as part of the
   resulting filename.

   Enabling DECC$UNIX_PATH_BEFORE_LOGNAME overrides the setting for
   DECC$DISABLE_TO_VMS_LOGNAME_TRANSLATION.
 

3  DECC$USE_JPI$_CREATOR
   When enabled, DECC$USE_JPI$_CREATOR determines the parent process
   ID in getppid by calling $GETJPI using item JPI$_CREATOR instead
   of JPI$_OWNER.

   This feature is only available on systems supporting POSIX style
   session identifiers.
 

3  DECC$USE_RAB64
   With DECC$USE_RAB64 enabled, open functions allocate a RAB64
   structure instead of the traditional RAB structure.

   This provides latent support for file buffers in 64-bit memory.
 

3  DECC$VALIDATE_SIGNAL_IN_KILL
   With DECC$VALIDATE_SIGNAL_IN_KILL enabled, a signal value that
   is in the range 0 to _SIG_MAX but is not supported by the C RTL
   generates an error with errno set to EINVAL, which makes the
   behavior the same as for raise.

   With this logical name disabled, validation of signals is
   restricted to checking that the signal value is in the range 0 to
   _SIG_MAX. If sys$sigprc fails, errno is set based on sys$sigprc
   exit status.
 

3  DECC$V62_RECORD_GENERATION
   OpenVMS Versions 6.2 and higher can output record files using
   different rules.

   With DECC$V62_RECORD_GENERATION enabled, the output mechanism
   follows the rules used for OpenVMS Version 6.2.
 

3  DECC$WRITE_SHORT_RECORDS
   The DECC$WRITE_SHORT_RECORDS feature logical supports a previous
   change to the fwrite function (to accommodate writing records
   with size less than the maximum record size), while retaining
   the legacy way of writing records to a fixed-length file as the
   default behavior:

   With DECC$WRITE_SHORT_RECORDS enabled, short-sized records
   (records with size less than the maximum record size) written at
   EOF are padded with zeros to align records on record boundaries.
   This is the behavior seen in OpenVMS Version 7.3-1 and some ACRTL
   ECOs of that time period.

   With DECC$WRITE_SHORT_RECORDS disabled, the legacy behavior
   of writing records with no padding is implemented. This is the
   recommended and default behavior.
 

3  DECC$XPG4_STRPTIME
   XPG5 support for strptime introduces pivoting year support so
   that years in the range 0 to 68 are in the 21st century, and
   years in the range 69-99 are in the 20th century.

   With DECC$XPG4_STRPTIME enabled, XPG5 support for the pivoting
   year is disabled and all years in the range 0 to 99 are in the
   current century.
 

2  a64l
   Converts a character string to a long integer.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdlib.h>

     long a64l  (const char *s);
 

3  Argument
 

s

   Pointer to the character string that is to be converted to a long
   integer.
 

3  Description
   The a64l and l64a functions are used to maintain numbers stored
   in base-64 ASCII characters as follows:

   o  a64l converts a character string to a long integer.

   o  l64a converts a long integer to a character string.

   Each character used for storing a long integer represents a
   numeric value from 0 through 63. Up to six characters can be
   used to represent a long integer.

   The characters are translated as follows:

   o  A period (.)  represents 0.

   o  A slash (/)  represents 1.

   o  The numbers 0 through 9 represent 2 through 11.

   o  Uppercase letters A through Z represent 12 through 37.

   o  Lowercase letters a through z represent 38 through 63.

   The a64l function takes a pointer to a base-64 representation,
   in which the first digit is the least significant, and returns
   a corresponding long value. If the string pointed to by the s
   parameter exceeds six characters, a64l uses only the first six
   characters.

   If the first six characters of the string contain a null
   terminator, a64l uses only characters preceding the null
   terminator.

   The a64l function translates a character string from left to
   right with the least significant number on the left, decoding
   each character as a 6-bit base-64 number.

   If s is the NULL pointer or if the string pointed to by s was
   not generated by a previous call to l64a, the behavior of a64l is
   unspecified.

   See also l64a.
 

3  Return_Values

   n                  Upon successful completion, the long value
                      resulting from conversion of the input string.
   0L                 Indicates that the string pointed to by s is
                      an empty string.
 

2  abort
   Sends the signal SIGABRT that terminates execution of the
   program.

   Format

     #include  <stdlib.h>

     void abort  (void);
 

2  abs
   Returns the absolute value of an integer.

   Format

     #include  <stdlib.h>

     int abs  (int x);
 

3  Argument
 

x

   An integer.
 

3  Return_Value

   x                  The absolute value of the input argument. If
                      the argument is LONG_MIN, abs returns LONG_
                      MIN because -LONG_MIN cannot fit in an int
                      variable.
 

2  access
   Checks a file to see whether a specified access mode is allowed.

                                  NOTE

      The access function does not accept network files as
      arguments.

   Format

     #include  <unistd.h>

     int access  (const char *file_spec, int mode);
 

3  Arguments
 

file_spec

   A character string that gives an OpenVMS or UNIX style file
   specification. The usual defaults and logical name translations
   are applied to the file specification.
 

mode

   Interpreted as shown in Interpretation of the mode Argument.

   Table REF-1 Interpretation of the mode Argument

   Mode
   Argument     Access Mode

   F_OK         Tests to see if the file exists
   X_OK         Execute
   W_OK         Write (implies delete access)
   R_OK         Read

   Combinations of access modes are indicated by ORing the values.
   For example, to check to see if a file has RWED access mode,
   invoke access as follows:

   access (file_spec, R_OK | W_OK | X_OK);
 

3  Description
   The access function checks a file to see whether a specified
   access mode is allowed. If the DECC$ACL_ACCESS_CHECK feature
   logical is enabled, this function checks OpenVMS Access Control
   Lists (ACLs) as well as the UIC protection.
 

3  Return_Values

   0                  Indicates that the access is allowed.
   -1                 Indicates that the access is not allowed.
 

3  Example

       #include <unistd.h>
       #include <stdlib.h>
       #include <stdio.h>

       main()
       {
           if (access("sys$login:login.com", F_OK)) {
               perror("ACCESS - FAILED");
               exit(2);
           }
       }
 

2  acos
   Returns the arc cosine of its argument.

   Format

     #include  <math.h>

     double acos  (double x);

     float acosf  (float x); (Integrity servers, Alpha)

     long double acosl  (long double x); (Integrity servers, Alpha)

     double acosd  (double x); (Integrity servers, Alpha)

     float acosdf  (float x); (Integrity servers, Alpha)

     long double acosdl  (long double x);

                         (Integrity servers, Alpha)
 

3  Argument
 

x

   A radian expressed as a real value in the domain [-1,1].
 

3  Description
   The acos functions compute the principal value of the arc cosine
   of x in the range [0,pi] radians for x in the domain [-1,1].

   The acosd functions compute the principal value of the arc cosine
   of x in the range [0,180] degrees for x in the domain [-1,1].

   For abs(x) > 1, the value of acos(x) is 0, and errno is set to
   EDOM.
 

2  acosh
   Returns the hyperbolic arc cosine of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double acosh  (double x);

     float acoshf  (float x);

     long double acoshl  (long double x);
 

3  Argument
 

x

   A radian expressed as a real value in the domain [1, +Infinity].
 

3  Description
   The acosh functions return the hyperbolic arc cosine of x for x
   in the domain [1, +Infinity], where acosh(x) = ln(x + sqrt(x**2 -
   1)).

   The acosh function is the inverse function of cosh where
   acosh(cosh(x)) = |x|.

   x < 1 is an invalid argument.
 

2  [w]addch
   Add a character to the window at the current position of the
   cursor.

   Format

     #include  <curses.h>

     int addch  (char ch);

     int waddch  (WINDOW *win, char ch);
 

3  Arguments
 

win

   A pointer to the window.
 

ch

   The character to be added. A new-line character (\n) clears the
   line to the end, and moves the cursor to the next line at the
   same x coordinate. A return character (\r) moves the cursor to
   the beginning of the line on the window. A tab character (\t)
   moves the cursor to the next tabstop within the window.
 

3  Description
   When the waddch function is used on a subwindow, it writes the
   character onto the underlying window as well.

   The addch routine performs the same function as waddch, but on
   the stdscr window.

   The cursor is moved after the character is written to the screen.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that writing the character would
                      cause the screen to scroll illegally. For more
                      information, see the scrollok function.
 

2  [w]addstr
   Add the string pointed to by str to the window at the current
   position of the cursor.

   Format

     #include  <curses.h>

     int addstr  (char *str);

     int waddstr  (WINDOW *win, char *str);
 

3  Arguments
 

win

   A pointer to the window.
 

str

   A pointer to a character string.
 

3  Description
   When the waddstr function is used on a subwindow, the string is
   written onto the underlying window as well.

   The addstr routine performs the same function as waddstr, but on
   the stdscr window.

   The cursor position changes as a result of calling this routine.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function causes the screen
                      to scroll illegally, but it places as much of
                      the string onto the window as possible. For
                      more information, see the scrollok function.
 

2  alarm
   Sends the signal SIGALRM (defined in the <signal.h> header file)
   to the invoking process after the number of seconds indicated by
   its argument has elapsed.

   Format

     #include  <unistd.h>

     unsigned int alarm  (unsigned int seconds); (ISO POSIX-1)

     int alarm  (unsigned int seconds); (Compatibility)
 

3  Argument
 

seconds

   Has a maximum limit of LONG_MAX seconds.
 

3  Description
   Calling the alarm function with a 0 argument cancels any pending
   alarms.

   Unless it is intercepted or ignored, the signal generated by
   alarm terminates the process. Successive alarm calls reinitialize
   the alarm clock. Alarms are not stacked.

   Because the clock has a 1-second resolution, the signal may
   occur up to 1 second early. If the SIGALRM signal is intercepted,
   resumption of execution may be held up due to scheduling delays.

   When the SIGALRM signal is generated, a call to SYS$WAKE is
   generated whether or not the process is hibernating. The pending
   wake causes the current pause() to return immediately (after
   completing any function that catches the SIGALRM).
 

3  Return_Value

   n                  The number of seconds remaining from a
                      previous alarm request.
 

2  asctime
   Converts a broken-down time in a tm structure into a 26-character
   string in the following form:

   Sun Sep 16 01:03:52 1984\n\0

   All fields have a constant width.

   Format

     #include  <time.h>

     char *asctime  (const struct tm *timeptr);

     char *asctime_r  (const struct tm *timeptr, char *buffer); 
                      
                                                 (ISO POSIX-1)
 

3  Arguments
 

timeptr

   A pointer to a structure of type tm, which contains the broken-
   down time.

   The tm structure is defined in the <time.h> header file, and also
   shown in tm Structure in the description of localtime.
 

buffer

   A pointer to a character array that is at least 26 bytes long.
   This array is used to store the generated date-and-time string.
 

3  Description
   The asctime and asctime_r functions convert the contents of tm
   into a 26-character string and returns a pointer to the string.

   The difference between asctime_r and asctime is that the former
   puts the result into a user-specified buffer. The latter puts
   the result into thread-specific static memory allocated by the
   Compaq C RTL, which can be overwritten by subsequent calls to
   ctime or asctime; you must make a copy if you want to save it.

   On success, asctime returns a pointer to the string; asctime_r
   returns its second argument. On failure, these functions return
   the NULL pointer.

   See the localtime function for a list of the members in tm.

                                  NOTE

      Generally speaking, UTC-based time functions can affect in-
      memory time-zone information, which is processwide data.
      However, if the system time zone remains the same during
      the execution of the application (which is the common case)
      and the cache of timezone files is enabled (which is the
      default), then the _r variant of the time functions asctime_
      r, ctime_r, gmtime_r and localtime_r, is both thread-safe
      and AST-reentrant.

      If, however, the system time zone can change during the
      execution of the application or the cache of timezone files
      is not enabled, then both variants of the UTC-based time
      functions belong to the third class of functions, which are
      neither thread-safe nor AST-reentrant.
 

3  Return_Values

   x                  A pointer to the string, if successful.
   NULL               Indicates failure.
 

2  asin
   Returns the arc sine of its argument.

   Format

     #include  <math.h>

     double asin  (double x);

     float asinf  (float x); (Integrity servers, Alpha)

     long double asinl  (long double x); (Integrity servers, Alpha)

     double asind  (double x); (Integrity servers, Alpha)

     float asindf  (float x); (Integrity servers, Alpha)

     long double asindl  (long double x);

                         (Integrity servers, Alpha)
 

3  Argument
 

x

   A radian expressed as a real number in the domain [-1,1].
 

3  Description
   The asin functions compute the principal value of the arc sine of
   x in the range [-pi/2,pi/2] radians for x in the domain [-1,1].

   The asind functions compute the principal value of the arc sine
   of x in the range [-90,90] degrees for x in the domain [-1,1].

   When abs(x) is greater than 1.0, the value of asin(x) is 0, and
   errno is set to EDOM.
 

2  asinh
   Returns the hyperbolic arc sine of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double asinh  (double x);

     float asinhf  (float x);

     long double asinhl  (long double x);
 

3  Argument
 

x

   A radian expressed as a real value in the domain [-Infinity,
   +Infinity].
 

3  Description
   The asinh functions return the hyperbolic arc sine of x for x
   in the domain [-Infinity, +Infinity], where asinh(x) = ln(x +
   sqrt(x**2 + 1)).

   The asinh function is the inverse function of sinh where
   asinh(sinh(x)) = x.
 

2  assert
   Used for implementing run-time diagnostics in programs.

   Format

     #include  <assert.h>

     void assert  (int expression);
 

3  Argument
 

expression

   An expression that has an int type.
 

3  Description
   When assert is executed, if expression is false (that is, it
   evaluates to 0), assert writes information about the particular
   call that failed (including the text of the argument, the name of
   the source file, and the source line number; the latter two are,
   respectively, the values of the preprocessing macros __FILE__
   and __LINE__)  to the standard error file in an implementation-
   defined format. Then, it calls the abort function.

   The assert function writes a message in the following form:

   Assertion failed:  expression, file aaa, line nnn

   If expression is true (that is, it evaluates to nonzero) or if
   the signal SIGABRT is being ignored, assert returns no value.

                                  NOTE

      If a null character ('\0') is part of the expression being
      asserted, then only the text up to and including the null
      character is printed, since the null character effectively
      terminates the string being output.

   Compiling with the CC command qualifier /DEFINE=NDEBUG or with
   the preprocessor directive #define NDEBUG ahead of the #include
   assert statement causes the assert function to have no effect.
 

3  Example

       #include <stdio.h>
       #include <assert.h>

       main()
       {
           printf("Only this and the assert\n");
           assert(1 == 2);     /* expression is FALSE */

   /* abort should be called so the printf will not happen. */

           printf("FAIL abort did not execute");
       }
 

2  atan

   Format

     #include  <math.h>

     double atan  (double x);

     float atanf  (float x); (Integrity servers, Alpha)

     long double atanl  (long double x); (Integrity servers, Alpha)

     double atand  (double x); (Integrity servers, Alpha)

     float atandf  (float x); (Integrity servers, Alpha)

     long double atandl  (long double x);

                         (Integrity servers, Alpha)
 

3  Argument
 

x

   A radian expressed as a real number.
 

3  Description
   The atan functions compute the principal value of the arc tangent
   of x in the range [-pi/2,pi/2] radians.

   The atand functions compute the principal value of the arc
   tangent of x in the range [-90,90] degrees.
 

2  atan2

   Format

     #include  <math.h>

     double atan2  (double y, double x);

     float atan2f  (float y, float x); (Integrity servers, Alpha)

     long double atan2l  (long double y, long double x);

                         (Integrity servers, Alpha)

     double atand2  (double y, double x);

                    (Integrity servers, Alpha)

     float atand2f  (float y, float x); (Integrity servers, Alpha)

     long double atand2l  (long double y, long double x);

                          (Integrity servers, Alpha)
 

3  Arguments
 

y

   A radian expressed as a real number.
 

x

   A radian expressed as a real number.
 

3  Description
   The atan2 functions compute the principal value of the arc
   tangent of y/x in the range [-pi,pi] radians. The sign of
   atan2 and atan2f is determined by the sign of y. The value of
   atan2(y,x) is computed as follows, where f is the number of
   fraction bits associated with the data type:

   Value of Input
   Arguments          Angle Returned

   x = 0 or y/x >     pi/2 * (sign y)
   2**(f+1)
   x > 0 and y/x <=   atan(y/x)
   2**(f+1)
   x < 0 and y/x <=   pi * (sign y) + atan(y/x)
   2**(f+1)

   The atand2 functions compute the principal value of the arc
   tangent of y/x in the range [-180,180] degrees. The sign of
   atand2 and atand2f is determined by the sign of y.

   The following are invalid arguments for the atan2 and atand2
   functions:

   Function                  Exceptional Argument

   atan2, atan2f, atan2l     x = y = 0
   atan2, atan2f, atan2l     |x| = |y| = Infinity
   atand2, atand2f, atand2l  x = y = 0
   atand2, atand2f, atand2l  |x| = |y| = Infinity
 

2  atanh
   Returns the hyperbolic arc tangent of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double atanh  (double x);

     float atanhf  (float x);

     long double atanhl  (long double x);
 

3  Argument
 

x

   A radian expressed as a real value in the domain [-1,1].
 

3  Description
   The atanh functions return the hyperbolic arc tangent of x.
   The atanh function is the inverse function of tanh where
   atanh(tanh(x)) = x.

   |x| > 1 is an invalid argument.
 

2  atexit
   Registers a function that is called without arguments at program
   termination.

   Format

     #include  <stdlib.h>

     int atexit  (void (*func) (void));
 

3  Argument
 

func

   A pointer to the function to be registered.
 

3  Return_Values

   0                  Indicates that the registration has succeeded.
   nonzero            Indicates failure.
 

3  Restriction
   The longjmp function cannot be executed from within the handler,
   because the destination address of the longjmp no longer exists.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>

       static void hw(void);

       main()
       {
           atexit(hw);
       }

       static void hw()
       {
               puts("Hello, world\n");
       }

     Running this example produces the following output:

       Hello, world
 

2  atof
   Converts an ASCII character string to a double-precision number.

   Format

     #include  <stdlib.h>

     double atof  (const char *nptr);
 

3  Argument
 

nptr

   A pointer to the character string to be converted to a double-
   precision number. The string is interpreted by the same rules
   that are used to interpret floating constants.
 

3  Description
   The string to be converted has the following format:

   [white-spaces][+|-]digits[radix-character][digits][e|E[+|-]integer]

   Where radix-character is defined in the current locale.

   The first unrecognized character ends the conversion.

   This function is equivalent to strtod(nptr, (char**) NULL).
 

3  Return_Values

   x                  The converted value.
   0                  Indicates an underflow or the conversion could
                      not be performed. The function sets errno to
                      ERANGE or EINVAL, respectively.
   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
 

2  atoi,atol
   Convert strings of ASCII characters to the appropriate numeric
   values.

   Format

     #include  <stdlib.h>

     int atoi  (const char *nptr);

     long int atol  (const char *nptr);
 

3  Argument
 

nptr

   A pointer to the character string to be converted to a numeric
   value.
 

3  Description
   The atoi and atol functions convert the initial portion of a
   string to its decimal int or long int value, respectively. The
   atoi and atol functions do not account for overflows resulting
   from the conversion. The string to be converted has the following
   format:

   [white-spaces][+|-]digits

   The function call atol (str) is equivalent to strtol (str,
   (char**)NULL, 10), and the function call atoi (str) is equivalent
   to (int) strtol (str, (char**)NULL, 10), except, in both cases,
   for the behavior on error.
 

3  Return_Value

   n                  The converted value.
 

2  atoq,atoll
   Convert strings of ASCII characters to the appropriate numeric
   values. atoll is a synonym for atoq.

   This function is OpenVMS Alpha and Integrity servers only. atoq.

   Format

     #include  <stdlib.h>

     __int64 atoq  (const char *nptr);

     __int64 atoll  (const char *nptr);
 

3  Argument
 

nptr

   A pointer to the character string to be converted to a numeric
   value.
 

3  Description
   The atoq (or atoll) function converts the initial portion of
   a string to its decimal __int64 value. This function does not
   account for overflows resulting from the conversion. The string
   to be converted has the following format:

   [white-spaces][+|-]digits

   The function call atoq (str) is equivalent to strtoq (str,
   (char**)NULL, 10), except for the behavior on error.
 

3  Return_Value

   n                  The converted value.
 

2  basename
   Returns the last component of a pathname.

   Format

     #include  <libgen.h>

     char *basename  (char *path);
 

3  Function_Variants
   The basename function has variants named _basename32 and 
   _basename64 for use with 32-bit and 64-bit pointer sizes,
   respectively.
 

3  Argument
 

path

   A UNIX style pathname from which the base pathname is extracted.
 

3  Description
   The basename function takes the UNIX style pathname pointed to
   by path and returns a pointer to the pathname's final component,
   deleting any trailing slash (/)  characters.

   If path consists entirely of the slash (/)  character, the
   function returns a pointer to the string "/".

   If path is a NULL pointer or points to an empty string, the
   function returns a pointer to the string ".".

   The basename function can modify the string pointed to by path.
 

3  Return_Values

   x                  A pointer to the final component of path.
   "/"                If path consists entirely of the '/'
                      character.
   "."                If path is a NULL pointer or points to an
                      empty string.
 

2  bcmp
   Compares byte strings.

   Format

     #include  <strings.h>

     void bcmp  (const void *string1, const void *string2, size_t length);
 

3  Arguments
 

string1, string2

   The byte strings to be compared.
 

length

   The length (in bytes) of the strings.
 

3  Description
   The bcmp function compares the byte string in string1 against the
   byte string in string2.

   Unlike the string functions, there is no checking for null bytes.
   Zero-length strings are always identical.

   Note that bcmp is equivalent to memcmp, which is defined by
   the ANSI C Standard. Therefore, using memcmp is recommended for
   portable programs.
 

3  Return_Values

   0                  The strings are identical.
   Nonzero            The strings are not identical.
 

2  bcopy
   Copies byte strings.

   Format

     #include  <strings.h>

     void bcopy  (const void *source, void *destination, size_t length);
 

3  Arguments
 

source

   Pointer to the source string.
 

destination

   Pointer to the destination string.
 

length

   The length (in bytes) of the string.
 

3  Description
   The bcopy function operates on variable-length strings of bytes.
   It copies the value of the length argument, in bytes, from the
   string in the source argument to the string in the destination
   argument.

   Unlike the string functions, there is no checking for null bytes.
   If the length argument is 0 (zero), no bytes are copied.

   Note that bcopy is equivalent to memcpy, which is defined by
   the ANSI C Standard. Therefore, using memcpy is recommended for
   portable programs.
 

2  box
   Draws a box around the window using the character vert as the
   character for drawing the vertical lines of the rectangle, and
   hor for drawing the horizontal lines of the rectangle.

   Format

     #include  <curses.h>

     int box  (WINDOW *win, char vert, char hor);
 

3  Arguments
 

win

   The address of the window.
 

vert

   The character for the vertical edges of the window.
 

hor

   The character for the horizontal edges of the window.
 

3  Description
   The box function copies boxes drawn on subwindows onto the
   underlying window. Use caution when using functions such as
   overlay and overwrite with boxed subwindows. Such functions copy
   the box onto the underlying window.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  brk
   Determines the lowest virtual address that is not used with the
   program.

   Format

     #include  <stdlib.h>

     void *brk  (unsigned long int addr);
 

3  Argument
 

addr

   The lowest address, which the function rounds up to the next
   multiple of the page size. This rounded address is called the
   break address.
 

3  Description
   An address that is greater than or equal to the break address
   and less than the stack pointer is considered to be outside the
   program's address space. Attempts to reference it will cause
   access violations.

   When a program is executed, the break address is set to the
   highest location defined by the program and data storage areas.
   Consequently, brk is needed only by programs that have growing
   data areas.
 

3  Return_Values

   n                  The new break address.
   (void *)(-1)       Indicates that the program is requesting too
                      much memory. errno and vaxc$errno are updated.
 

3  Restriction
   Unlike other C library implementations, the Compaq C RTL memory
   allocation functions (such as malloc) do not rely on brk or
   sbrk to manage the program heap space. Consequently, on OpenVMS
   systems, calling brk or sbrk can interfere with memory allocation
   routines. The brk and sbrk functions are provided only for
   compatibility purposes.
 

2  bsearch
   Performs a binary search. It searches an array of sorted objects
   for a specified object.

   Format

     #include  <stdlib.h>

     void *bsearch  (const void *key, const void *base, size_t 
                     nmemb, size_t size, int (*compar)
                    (const void *, const void *));
 

3  Function_Variants
   The bsearch function has variants named _bsearch32 and _bsearch64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

key

   A pointer to the object to be sought in the array. This pointer
   should be of type pointer-to-object and cast to type pointer-to-
   void.
 

base

   A pointer to the initial member of the array. This pointer should
   be of type pointer-to-object and cast to type pointer-to-void.
 

nmemb

   The number of objects in the array.
 

size

   The size of an object, in bytes.
 

compar

   A pointer to the comparison function.
 

3  Description
   The array must first be sorted in increasing order according to
   the specified comparison function pointed to by compar.

   Two arguments are passed to the comparison function pointed to
   by compar. The two arguments point to the objects being compared.
   Depending on whether the first argument is less than, equal to,
   or greater than the second argument, the comparison function must
   return an integer less than, equal to, or greater than 0.

   It is not necessary for the comparison function (compar) to
   compare every byte in the array. Therefore, the objects in the
   array can contain arbitrary data in addition to the data being
   compared.

   Since it is declared as type pointer-to-void, the value returned
   must be cast or assigned into type pointer-to-object.
 

3  Return_Values

   x                  A pointer to the matching member of the array
                      or a null pointer if no match is found.
   NULL               Indicates that the key cannot be found in the
                      array.
 

3  Example

#include <stdio.h>
#include <stdlib.h>

#define SSIZE 30

extern int compare();  /* prototype for comparison function */

int array[SSIZE] = {30, 1, 29, 2, 28, 3, 27, 4, 26, 5,
                    24, 6, 23, 7, 22, 8, 21, 9, 20, 10,
                    19, 11, 18, 12, 17, 13, 16, 14, 15, 25};

 /*  This program takes an unsorted array, sorts it using qsort, */
 /*  and then calls bsearch for each element in the array,       */
 /*  making sure that bsearch returns the correct element.       */

main()
{
    int i;
    int failure = FALSE;
    int *rkey;

    qsort(array, SSIZE, sizeof (array[0]), &compare);

    /* search for each element */
    for (i = 0; i < SSIZE - 1; i++) {
        /* search array element i */
        rkey = bsearch((array + i), array, SSIZE,
                        sizeof(array[0]), &compare);
        /* check for successful search */
        if (&array[i] != rkey) {
            printf("Not in array, array element %d\n", i);
            failure = TRUE;
            break;
        }
    }
    if (!failure)
        printf("All elements successfully found!\n");
}

 /*  Simple comparison routine.  */
 /*                              */
 /*  Returns:  = 0 if a == b     */
 /*            < 0 if a < b      */
 /*            > 0 if a > b      */

int compare(int *a, int *b)
{
    return (*a - *b);
}

     This example program outputs the following:

       All elements successfully found!
 

2  btowc
   Converts a one-byte multibyte character to a wide character in
   the initial shift state.

   Format

     #include  <wchar.h>

     wint_t btowc  (int c);
 

3  Argument
 

c

   The character to be converted to a wide-character representation.
 

3  Description
   The btowc function determines whether (unsigned char)c is a valid
   one-byte multibyte character in the initial shift state, and if
   so, returns a wide-character representation of that character.
 

3  Return_Values

   x                  The wide-character representation of unsigned
                      char c.
   WEOF               Indicates an error. The c argument has the
                      value EOF or does not constitute a valid one-
                      byte multibyte character in the initial shift
                      state.
 

2  bzero
   Copies null characters into byte strings.

   Format

     #include  <strings.h>

     void bzero  (void *string, size_t length);
 

3  Arguments
 

string

   Specifies the byte string into which you want to copy null
   characters.
 

length

   Specifies the length (in bytes) of the string.
 

3  Description
   The bzero function copies null characters ('\0') into the byte
   string pointed to by string for length bytes. If length is 0
   (zero), then no bytes are copied.
 

2  cabs
   Returns the absolute value of a complex number.

   Format

     #include  <math.h>

     double cabs  (cabs_t z);

     float cabsf  (cabsf_t z); (Integrity servers, Alpha)

     long double cabsl  (cabsl_t z); (Integrity servers, Alpha)
 

3  Argument
 

z

   A structure of type cabs_t, cabsf_t, or cabsl_t. These types are
   defined in the <math.h> header file as follows:

   typedef struct {double x,y;} cabs_t;

   typedef struct { float x, y; } cabsf_t; (Integrity servers, Alpha)
   typedef struct { long double x, y; } cabsl_t; (Integrity servers, Alpha)
 

3  Description
   The cabs functions return the absolute value of a complex number
   by computing the Euclidean distance between its two points as the
   square root of their respective squares:

   sqrt(x2 + y2)

   On overflow, the return value is undefined.

   The cabs, cabsf, and cabsl functions are equivalent to the hypot,
   hypotf, and hypotl functions, respectively.
 

2  cacos
   Returns the complex arc cosine of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex cacos  (double complex z);

     float complex cacosf  (float complex z);

     long double complex cacosl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The cacos functions compute the complex arc cosine of z, with
   branch cuts outside the interval [-1, +1] along the real axis.
 

3  Return_Values

   n                  The complex arc cosine value, in the range
                      of a strip mathematically unbounded along the
                      imaginary axis and in the interval [0, &#960;]
                      along the real axis.
 

2  cacosh
   Returns the complex arc hyperbolic cosine of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex cacosh  (double complex z);

     float complex cacoshf  (float complex z);

     long double complex cacoshl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The cacosh functions compute the complex arc hyperbolic cosine of
   z, with a branch cut at values less than 1 along the real axis.
 

3  Return_Values

   n                  The complex arc hyperbolic cosine value, in
                      the range of a half-strip of non-negative
                      values along the real axis and in the interval
                      [-i&#960;, +i&#960;] along the imaginary axis.
 

2  calloc
   Allocates an area of zeroed memory. This function is AST-
   reentrant.

   Format

     #include  <stdlib.h>

     void *calloc  (size_t number, size_t size);
 

3  Function_Variants
   The calloc function has variants named _calloc32 and _calloc64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

number

   The number of items to be allocated.
 

size

   The size of each item.
 

3  Description
   The calloc function initializes the items to 0. The maximum
   amount of memory allocated at once is limited to 0xFFFFD000.

   See also malloc and realloc.
 

3  Return_Values

   x                  The address of the first byte, which
                      is aligned on a quadword boundary
                      (Alpha only) or an octaword boundary
                      (Integrity servers(ONLY)) .
   NULL               Indicates an inability to allocate the space.
 

2  carg
   Returns the phase angle of its complex argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double carg  (double complex z);

     float cargf  (float complex z);

     long double cargl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The carg functions compute the argument (also called phase angle)
   of z, with a branch cut along the negative real axis.
 

3  Return_Values

   n                  The value of the argument of z, in the
                      interval [-&#960;, +&#960;].
 

2  casin
   Returns the complex arc sine of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex casin  (double complex z);

     float complex casinf  (float complex z);

     long double complex casinl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The casin functions compute the complex arc sine of z, with
   branch cuts outside the interval [-1, +1] along the real axis.
 

3  Return_Values

   n                  The complex arc sine value, in the range of
                      a strip mathematically unbounded along the
                      imaginary axis and in the interval [-&#960;/2,
                      +&#960;/2] along the real axis.
 

2  casinh
   Returns the complex arc hyperbolic sine of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex casinh  (double complex z);

     float complex casinhf  (float complex z);

     long double complex casinhl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The casinh functions compute the complex arc hyperbolic sine
   of z, with branch cuts outside the interval [-i, +i] along the
   imaginary axis.
 

3  Return_Values

   n                  The complex arc hyperbolic sine value, in the
                      range of a strip mathematically unbounded
                      along the real axis and in the interval
                      [-i&#960;/2, +i&#960;/2] along the imaginary
                      axis.
 

2  catan
   Returns the complex arc tangent of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex catan  (double complex z);

     float complex catanf  (float complex z);

     long double complex catanl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The catan functions compute the complex arc tangent of z, with
   branch cuts outside the interval [-i, +i] along the imaginary
   axis.
 

3  Return_Values

   n                  The complex arc tangent value, in the range
                      of a strip mathematically unbounded along the
                      imaginary axis and in the interval [-&#960;/2,
                      +&#960;/2] along the real axis.
 

2  catanh
   Returns the complex arc hyperbolic tangent of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex catanh  (double complex z);

     float complex catanhf  (float complex z);

     long double complex catanhl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The catanh functions compute the complex arc hyperbolic tangent
   of z, with branch cuts outside the interval [-1, +1] along the
   imaginary axis.
 

3  Return_Values

   n                  The complex arc hyperbolic tangent value, in
                      the range of a strip mathematically unbounded
                      along the real axis and in the interval
                      [-i&#960;/2, +i&#960;/2] along the imaginary
                      axis.
 

2  catclose
   Closes a message catalog.

   Format

     #include  <nl_types.h>

     int catclose  (nl_catd catd);
 

3  Argument
 

catd

   A message catalog descriptor. This is returned by a successful
   call to catopen.
 

3  Description
   The catclose function closes the message catalog referenced by
   catd and frees the catalog file descriptor.
 

3  Return_Values

   0                  Indicates that the catalog was successfully
                      closed.
   -1                 Indicates that an error occurred. The function
                      sets errno to the following value:

                      o  EBADF - The catalog descriptor is not
                         valid.
 

2  catgets
   Retrieves a message from a message catalog.

   Format

     #include  <nl_types.h>

     char *catgets  (nl_catd catd, int set_id, int msg_id, const char *s);
 

3  Function_Variants
   The catgets function has variants named _catgets32 and _catgets64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

catd

   A message catalog descriptor. This is returned by a successful
   call to catopen.
 

set_id

   An integer set identifier.
 

msg_id

   An integer message identifier.
 

s

   A pointer to a default message string that is returned by the
   function if the message cannot be retrieved.
 

3  Description
   The catgets function retrieves a message identified by set_id
   and msg_id, in the message catalog catd. The message is stored in
   a message buffer in the nl_catd structure, which is overwritten
   by subsequent calls to catgets. If a message string needs to
   be preserved, it should be copied to another location by the
   program.
 

3  Return_Values

   x                  Pointer to the retrieved message.
   s                  Pointer to the default message string.
                      Indicates that the function is not able
                      to retrieve the requested message from
                      the catalog. This condition can arise if
                      the requested pair (set_d, msg_id) does
                      not represent an existing message from the
                      open catalog, or it indicates that an error
                      occurred. If an error occurred, the function
                      sets errno to one of the following values:

                      o  EBADF - The catalog descriptor is not
                         valid.

                      o  EVMSRR - An OpenVMS I/O read error;
                         the OpenVMS error code can be found in
                         vaxc$errno.
 

3  Example

#include <nl_types.h>
#include <locale.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <unixio.h>

 /* This test makes use of all the message catalog routines. catopen  */
 /* opens the catalog ready for reading, then each of the three       */
 /* messages in the catalog are extracted in turn using catgets and   */
 /* printed out. catclose closes the catalog after use.               */
 /* The catalog source file used to create the catalog is as follows: */
 /* $ This is a message file
 * $
 * $quote "
 * $ another comment line
 * $set 1
 * 1 "First set, first message"
 * 2 "second message - This long message uses a backslash \
 * for continuation."
 * $set 2
 * 1 "Second set, first message"                                      */

char *default_msg = "this is the first message.";

main()
{
  nl_catd catalog;
  int msg1,
      msg2,
      retval;

  char *cat = "sys$disk:[]catgets_example.cat"; /*Force local catalog*/

  char *msgtxt;

  char string[128];

  /* Create the message test catalog */

  system("gencat catgets_example.msgx catgets_example.cat") ;

  if ((catalog = catopen(cat, 0)) == (nl_catd) - 1) {
      perror("catopen");
      exit(EXIT_FAILURE);
  }

  msgtxt = catgets(catalog, 1, 1, default_msg);
  printf("%s\n", msgtxt);

  msgtxt = catgets(catalog, 1, 2, default_msg);
  printf("%s\n", msgtxt);

  msgtxt = catgets(catalog, 2, 1, default_msg);
  printf("%s\n", msgtxt);

  if ((retval = catclose(catalog)) == -1) {
      perror("catclose");
      exit(EXIT_FAILURE);
  }

  delete("catgets_example.cat;") ;  /* Remove the test catalog */
}

     Running the example program produces the following result:

       First set, first message
       second message - This long message uses a backslash for
                                                 continuation.
       Second set, first message
 

2  catopen
   Opens a message catalog.

   Format

     #include  <nl_types.h>

     nl_catd catopen  (const char *name, int oflag);
 

3  Arguments
 

name

   The name of the message catalog to open.
 

oflag

   An object of type int that determines whether the locale set for
   the LC_MESSAGES category in the current program's locale or the
   logical name LANG is used to search for the catalog file.
 

3  Description
   The catopen function opens the message catalog identified by
   name.

   If name contains a colon (:),  a square opening bracket ([), or
   an angle bracket (<),  or is defined as a logical name, then it
   is assumed that name is the complete file specification of the
   catalog.

   If it does not include these characters, catopen assumes that
   name is a logical name pointing to an existing catalog file. If
   name is not a logical name, then the logical name NLSPATH is used
   to define the file specification of the message catalog. NLSPATH
   is defined in the user's process. If the NLSPATH logical name is
   not defined, or no message catalog can be opened in any of the
   components specified by the NLSPATH, then the SYS$NLSPATH logical
   name is used to search for a message catalog file.

   Both NLSPATH and SYS$NLSPATH are comma-separated lists of
   templates. The catopen function uses each template to construct a
   file specification. For example, NLSPATH could be defined as:

DEFINE NLSPATH SYS$SYSROOT:[SYS$I18N.MSG]%N.CAT,SYS$COMMON:[SYSMSG]%N.CAT

   In this example, catopen first searches the directory
   SYS$SYSROOT:[SYS$I18N.MSG] for the named catalog. If the named
   catalog is not found there, the directory SYS$COMMON:[SYSMSG] is
   searched. The catalog name is constructed by substituting %N with
   the name passed to catopen, and adding the .cat suffix. %N is
   known as a substitution field. The following substitution fields
   are valid:


   Field Meaning

   %N    Substitute the name passed to catopen
   %L    Substitute the locale name.

         The period (.)  and at-sign (@)  characters in the locale
         name are replaced by an underscore (_)  character.

         For example, the "zh_CN.dechanzi@radical" locale name
         results in a substitution of ZH_CN_DECHANZI_RADICAL.
   %l    Substitute the language part of the locale name. For
         example, the language part of the en_GB.ISO8859-1 locale
         name is en.
   %t    Substitute the territory part of the locale name. For
         example, the territory part of the en_GB.ISO8859-1 locale
         is GB.
   %c    Substitute the codeset name from the locale name. For
         example, the codeset name of the en_GB.ISO8859-1 locale
         name is ISO8859-1.

   If the oflag argument is set to NL_CAT_LOCALE, then the
   current locale as defined for the LC_MESSAGES category is
   used to determine the substitution for the %L, %l, %t, and %c
   substitution fields. If the oflag argument is set to 0, then the
   value of the LANG environment variable is used as a locale name
   to determine the substitution for these fields. Note that using
   NL_CAT_LOCALE conforms to the XPG4 specification while a value of
   0 (zero) exists for the purpose of preserving XPG3 compatibility.
   Note also, that catopen uses the value of the LANG environment
   variable without checking whether the program's locale can be set
   using this value. That is, catopen does not check whether this
   value can serve as a valid locale argument in the setlocale call.

   If the substitution value is not defined, an empty string is
   substituted.

   A leading comma or two adjacent commas (,,) is equivalent to
   specifying %N. For example,

   DEFINE NLSPATH ",%N.CAT,SYS$COMMON:[SYSMSG.%L]%N.CAT"

   In this example, catopen searches in the following locations in
   the order shown:

   1. name (in the current directory)

   2. name.cat (in the current directory)

   3. SYS$COMMON:[SYSMSG.locale_name]name.cat
 

3  Return_Values

   x                  A message catalog file descriptor. Indicates
                      the call was successful. This descriptor is
                      used in calls to catgets and catclose.
   (nl_catd) -1       Indicates an error occurred. The function sets
                      errno to one of the following values:

                      o  EACCES - Insufficient privilege or file
                         protection violation, or file currently
                         locked by another user.

                      o  EMFILE - Process channel count exceeded.

                      o  ENAMETOOLONG - The full file specification
                         for message catalog is too long

                      o  ENOENT - Unable to find the requested
                         message catalog.

                      o  ENOMEM - Insufficient memory available.

                      o  ENOTDIR - Part of the name argument is not
                         a valid directory.

                      o  EVMSERR - An error occurred that does not
                         match any errno value. Check the value of
                         vaxc$errno.
 

2  cbrt
   Returns the rounded cube root of y.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double cbrt  (double y);

     float cbrtf  (float y);

     long double cbrtl  (long double y);
 

3  Argument
 

y

   A real number.
 

2  ccos
   Returns the complex cosine of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex ccos  (double complex z);

     float complex ccosf  (float complex z);

     long double complex ccosl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The ccos functions return the complex cosine of z.
 

3  Return_Values

   x                  The complex cosine value.
 

2  ccosh
   Returns the complex hyperbolic cosine of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex ccosh  (double complex z);

     float complex ccoshf  (float complex z);

     long double complex ccoshl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The ccosh functions return the complex hyperbolic cosine of z.
 

3  Return_Values

   x                  The complex hyperbolic cosine value.
 

2  ceil
   Returns the smallest integer that is greater than or equal to its
   argument.

   Format

     #include  <math.h>

     double ceil  (double x);

     float ceilf  (float x); (Integrity servers, Alpha)

     long double ceill  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A real value.
 

3  Return_Value

   n                  The smallest integer greater than or equal to
                      the function argument.
 

2  cexp
   Returns the complex exponent of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex cexp  (double complex z);

     float complex cexpf  (float complex z);

     long double complex cexpl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The cexp functions compute the complex exponential value of
   z, defined as e**z, where e is the constant used as a base for
   natural logarithms.
 

3  Return_Values

   x                  The complex exponential value of the argument.
 

2  cfree
   Makes available for reallocation the area allocated by a previous
   calloc, malloc, or realloc call. This function is AST-reentrant.

   Format

     #include  <stdlib.h>

     void cfree  (void *ptr);
 

3  Argument
 

ptr

   The address returned by a previous call to malloc, calloc, or
   realloc.
 

3  Description
   The contents of the deallocated area are unchanged.

   In Compaq C for OpenVMS Systems, the free and cfree functions
   are equivalent. Some other C implementations use free with malloc
   or realloc, and cfree with calloc. However, since the ANSI C
   standard does not include cfree, using free may be preferable.

   See also free.
 

2  chdir
   Changes the default directory.

   Format

     #include  <unistd.h>

     int chdir  (const char *dir_spec); (ISO POSIX-1)

     int chdir  (const char *dir_spec, . . . ); (DEC C Extension)
 

3  Arguments
 

dir_spec

   A null-terminated character string naming a directory in either
   an OpenVMS or UNIX style specification.
 

 . . .

   This argument is an Compaq C extension available when not
   defining any of the standards-related feature-test macros and not
   compiling in strict ANSI C mode (/STANDARD=ANSI89). The argument
   is an optional flag of type int that is significant only when
   calling chdir from USER mode.

   If the value of the flag is 1, the new directory is effective
   across images. If the value is not 1, the original default
   directory is restored when the image exits.
 

3  Description
   The chdir function changes the default directory. The change can
   be permanent or temporary. Permanent means that the new directory
   remains as the default directory after the image exits. Temporary
   means that on image exit, the default is set to whatever it was
   before the execution of the image.

   There are two ways of making the change permanent:

   o  Call chdir from USER mode with the second argument set to 1.

   o  Call chdir from SUPERVISOR or EXECUTIVE mode, regardless of
      the value of the second argument.

   Otherwise, the change is temporary.
 

3  Return_Values

   0                  Indicates that the directory is successfully
                      changed to the given name.
   -1                 Indicates that the change attempt has failed.
 

2  chmod
   Changes the file protection of a file.

   Format

     #include  <stat.h>

     int chmod  (const char *file_spec, mode_t mode);
 

3  Arguments
 

file_spec

   The name of an OpenVMS or UNIX style file specification.
 

mode

   A file protection. Modes are constructed by performing a bitwise
   OR on any of the values shown in File Protection Values and Their
   Meanings.

   Table REF-2 File Protection Values and Their Meanings

   Value  Privilege

   0400   OWNER:READ
   0200   OWNER:WRITE
   0100   OWNER:EXECUTE
   0040   GROUP:READ
   0020   GROUP:WRITE
   0010   GROUP:EXECUTE
   0004   WORLD:READ
   0002   WORLD:WRITE
   0001   WORLD:EXECUTE

   When you supply a mode value of 0, the chmod function gives the
   file the user's default file protection.

   The system is given the same privileges as the owner. A WRITE
   privilege also implies a DELETE privilege.
 

3  Description
   You must have a WRITE privilege for the file specified to change
   the mode.

   The C RTL does not support the S_ISVTX bit. Setting the S_ISVTX
   mode has no effect.
 

3  Return_Values

   0                  Indicates that the mode is successfully
                      changed.
   -1                 Indicates that the change attempt has failed.
 

2  chown
   Changes the user ID and group ID of the specified file.

   Format

     #include  <unistd.h>

     int chown  (const char *file_spec, uid_t owner, gid_t group);
 

3  Arguments
 

file_spec

   The address of an ASCII filename.
 

owner

   The new user ID of the file.
 

group

   The new group ID of the file.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates failure.
 

2  cimag
   Returns the imaginary part of its complex argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double cimag  (double complex z);

     float cimagf  (float complex z);

     long double cimagl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The cimag functions return the imaginary part of z as a real
   number.
 

3  Return_Values

   x                  The imaginary part value.
 

2  [w]clear
   Erase the contents of the specified window and reset the cursor
   to coordinates (0,0). The clear function acts on the stdscr
   window.

   Format

     #include  <curses.h>

     int clear();

     int wclear  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  clearerr
   Resets the error and end-of-file indicators for a file (so that
   ferror and feof will not return a nonzero value).

   Format

     #include  <stdio.h>

     void clearerr  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

2  clearerr_unlocked
   Same as the clearerr function, except used only within a scope
   protected by flockfile and funlockfile.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     void clearerr_unlocked  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The reentrant version of the clearerr function is locked against
   multiple threads calling it simultaneously. This incurs overhead
   to ensure integrity of the stream. The unlocked version of this
   call, clearerr_unlocked can be used to avoid the overhead. The
   clearerr_unlocked macro is functionally identical to the clearerr
   macro, except that it is not required to be implemented in a
   thread-safe manner. The clearerr_unlocked function can be safely
   used only within a scope that is protected by the flockfile and
   funlockfile functions used as a pair. The caller must ensure that
   the stream is locked before clearerr_unlocked is used.

   See also flockfile, ftrylockfile, and funlockfile.
 

2  clearok
   Sets the clear flag for the window.

   Format

     #include  <curses.h>

     clearok  (WINDOW *win, bool boolf);
 

3  Arguments
 

win

   The entire size of the terminal screen. You can use the windows
   stdscr and curscr with clearok.
 

boolf

   A Boolean value of TRUE or FALSE. If the argument is TRUE, this
   forces a clearscreen to be printed on the next call to refresh,
   or stops the screen from being cleared if boolf is FALSE.

   The type bool is defined in the <curses.h> header file as
   follows:

   #define bool int
 

3  Description
   Unlike the clear function, the clearok function does not alter
   the contents of the window. If the win argument is curscr, the
   next call to refresh causes a clearscreen, even if the window
   passed to refresh is not a window the size of the entire terminal
   screen.
 

2  clock
   Determines the CPU time (in 10-millisecond units) used since the
   beginning of the process. The time reported is the sum of the
   user and system times of the calling process and any terminated
   child processes for which the calling process has executed wait
   or system.

   Format

     #include  <time.h>

     clock_t clock  (void);
 

3  Description
   The value returned by the clock function must be divided by the
   value of the CLK_TCK, as defined in the standard header file
   <time.h>, to obtain the time in seconds.

   The type clock_t is defined in the <time.h> header file as
   follows:

   typedef long int clock_t;

   Only the accumulated times for child processes running a C main
   program or a program that calls VAXC$CRTL_INIT or DECC$CRTL_INIT
   are included.

   A typical usage of the clock function is to call it after a
   program does its initial setup, and then again after the program
   executes the code to be timed. Then subtract the two values to
   give elapsed CPU time.
 

3  Return_Values

   n                  The processor time used.
   -1                 Indicates that the processor time used is not
                      available.
 

2  clock_getres
   Gets the resolution for the specified clock.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <time.h>

     int clock_getres  (clockid_t clock_id, struct timespec *res);
 

3  Arguments
 

clock_id

   The clock type used to obtain the resolution. The CLOCK_REALTIME
   clock is supported and represents the TIME-OF-DAY clock for the
   system.
 

res

   A pointer to the timespec data structure that receives the value
   of the clock's resolution.
 

3  Description
   The clock_getres function obtains the resolution value for the
   specified clock. Clock resolutions are implementation-dependent
   and cannot be set by a process.

   If the res argument is not NULL, the resolution of the specified
   clock is stored in the location pointed to by res.

   If res is NULL, the clock resolution is not stored.

   If the time argument (tp) of clock_settime is not a multiple of
   res, then the value is truncated to a multiple of res.

   On success, the function returns 0.

   On failure, the function returns -1 and sets errno to indicate
   the error.

   See also clock_gettime, clock_settime, time, and ctime.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates failure; errno is set to the
                      following value:

                      o  EINVAL - The clock_id argument does not
                         specify a known clock.
 

2  clock_gettime
   Returns the current time (in seconds and nanoseconds) for the
   specified clock.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <time.h>

     int clock_gettime  (clockid_t clock_id, struct timespec *tp);
 

3  Arguments
 

clock_id

   The clock type used to obtain the time for the clock that is
   set. The CLOCK_REALTIME clock is supported and represents the
   TIME-OF-DAY clock for the system.
 

tp

   A pointer to a timespec data structure.
 

3  Description
   The clock_gettime function returns the current tp value for the
   specified clock, clock_id.

   On success, the function returns 0.

   On failure, the function returns -1 and sets errno to indicate
   the error.

   See also clock_getres, clock_settime, time, and ctime.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates failure; errno is set to the
                      following value:

                      o  EINVAL - The clock_id argument does not
                         specify a known clock, or the tp argument
                         specifies a nanosecond value less than 0 or
                         greater than or equal to 1 billion.
 

2  clock_settime
   Sets the specified clock.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <time.h>

     int clock_settime  (clockid_t clock_id, const struct timespec *tp);
 

3  Arguments
 

clock_id

   The clock type used for the clock that is to be set. The CLOCK_
   REALTIME clock is supported and represents the TIME-OF-DAY clock
   for the system.
 

tp

   A pointer to a timespec data structure.
 

3  Description
   The clock_settime function sets the specified clock, clock_id,
   to the value specified by tp. Time values that are between two
   consecutive non-negative integer multiples of the resolution of
   the specified clock are truncated down to the smaller multiple of
   the resolution.

   A clock can be systemwide (that is, visible to all processes)
   or per-process (measuring time that is meaningful only within a
   process).

   The CLOCK_REALTIME clock, defined in <time.h>, represents the
   realtime clock for the system. For this clock, the values
   specified by clock_settime and returned by clock_gettime
   represent the amount of time elapsed, in seconds and nanoseconds,
   since the Epoch. The Epoch is defined as 00:00:00:00 January 1,
   1970 Greenwich Mean Time (GMT).

   You must have OPER, LOG_IO, and SYSPRV privileges to use the
   clock_settime function.

   On success, the function returns 0.

   On failure, the function returns -1 and sets errno to indicate
   the error.

   See also clock_getres, clock_gettime, time, and ctime.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates failure; errno is set to the
                      following value:

                      o  EINVAL - The clock_id argument does not
                         specify a known clock, or the tp argument
                         is outside the range for the given clock_id
                         or specifies a nanosecond value less than 0
                         or greater than or equal to 1 billion.

                      o  EPERM - The requesting process does not
                         have the appropriate privilege to set the
                         specified clock.
 

2  clog
   Returns the complex natural (base e) logarithm of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex clog  (double complex z);

     float complex clogf  (float complex z);

     long double complex clogl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The clog functions return the complex natural (base e) logarithm
   of z, with a branch cut along the negative real axis.
 

3  Return_Values

   x                  The complex natural logarithm value in the
                      range of a strip mathematically unbounded
                      along the real axis and in the interval [-
                      i&#960;, +i&#960;] along the imaginary axis.
 

2  close
   Closes the file associated with a file descriptor.

   Format

     #include  <unistd.h>

     int close  (int file_desc);
 

3  Argument
 

file_desc

   A file descriptor.
 

3  Description
   The close function tries to write buffered data by using an
   implicit call to fflush. If the write fails (because the disk
   is full or the user's quota was exceeded, for example), close
   continues executing. It closes the OpenVMS channel, deallocates
   any buffers, and releases the memory associated with the file
   descriptor (or FILE pointer). Any buffered data is lost, and the
   file descriptor (or FILE pointer) no longer refers to the file.

   If your program needs to recover from errors when flushing
   buffered data, it should make an explicit call to fsync (or
   fflush) before calling close.
 

3  Return_Values

   0                  Indicates that the file is properly closed.
   -1                 Indicates that the file descriptor is
                      undefined or an error occurred while the file
                      was being closed (for example, if the buffered
                      data cannot be written out).
 

3  Example

       #include <unistd.h>

       int fd;
          .
          .
          .
       fd = open ("student.dat", 1);
          .
          .
          .
       close(fd);
 

2  closedir
   Closes directories.

   Format

     #include  <dirent.h>

     int closedir  (DIR *dir_pointer);
 

3  Argument
 

dir_pointer

   Pointer to the dir structure of an open directory.
 

3  Description
   The closedir function closes a directory stream and frees
   the structure associated with the dir_pointer argument. Upon
   return, the value of dir_pointer does not necessarily point to an
   accessible object of the type DIR.

   The type DIR, which is defined in the <dirent.h> header file,
   represents a directory stream that is an ordered sequence of
   all the directory entries in a particular directory. Directory
   entries represent files. You can remove files from or add files
   to a directory asynchronously to the operation of the readdir
   function.

                                  NOTE

      An open directory must always be closed with the closedir
      function to ensure that the next attempt to open the
      directory is successful.
 

3  Example

     The following example shows how to search a directory for the
     entry name, using the opendir, readdir, and closedir functions:

       #include <dirent.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>

       #define FOUND     1
       #define NOT_FOUND 0

       static int dir_example(const char *name, unsigned int unix_style)
       {
           DIR *dir_pointer;
           struct dirent *dp;

           if ( unix_style )
               dir_pointer = opendir(".");
           else
               dir_pointer = opendir(getenv("PATH"));

           if ( !dir_pointer ) {
               perror("opendir");
               return NOT_FOUND;
           }

           /* Note, that if opendir() was called with UNIX style file  */
           /* spec like ".", readdir() will return only a single       */
           /* version of each file in the directory. In this case the  */
           /* name returned in d_name member of the dirent structure   */
           /* will contain only file name and file extension fields,   */
           /* both lowercased like "foo.bar".                          */

           /* If opendir() was called with OpenVMS style file spec,    */
           /* readdir() will return every version of each file in the  */
           /* directory. In this case the name returned in d_name      */
           /* member of the dirent structure will contain file name,   */
           /* file extension and file version fields. All in upper     */
           /* case, like "FOO.BAR;1".                                  */

           for ( dp = readdir(dir_pointer);
                 dp && strcmp(dp->d_name, name);
                 dp = readdir(dir_pointer) )
               ;

           closedir(dir_pointer);

           if ( dp != NULL )
               return FOUND;
           else
               return NOT_FOUND;
       }

       int main(void)
       {
          char *filename = "foo.bar";
          FILE *fp;

          remove(filename);

          if ( !(fp = fopen(filename, "w")) ) {
               perror("fopen");
               return (EXIT_FAILURE);
          }

          if ( dir_example( "FOO.BAR;1", 0 ) == FOUND )
               puts("OpenVMS style: found");
          else
               puts("OpenVMS style: not found");

          if ( dir_example( "foo.bar", 1 ) == FOUND )
               puts("UNIX style: found");
          else
               puts("UNIX style: not found");

          fclose(fp);
          remove(filename);
          return( EXIT_SUCCESS );
       }
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error and is further specified in
                      the global errno.
 

2  [w]clrattr
   Deactivate the video display attribute attr within the window.
   The clrattr function acts on the stdscr window.

   Format

     #include  <curses.h>

     int clrattr  (int attr);

     int wclrattr  (WINDOW *win, int attr);
 

3  Arguments
 

win

   A pointer to the window.
 

attr

   Video display attributes that can be blinking, boldface, reverse
   video, and underlining; they are represented by the defined
   constants _BLINK, _BOLD, _REVERSE, and _UNDERLINE. To clear
   multiple attributes, separate them with a bitwise OR operator
   (|) as follows:

   clrattr(_BLINK | _UNDERLINE);
 

3  Description
   These functions are specific to Compaq C for OpenVMS Systems and
   are not portable.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  [w]clrtobot
   Erase the contents of the window from the current position of the
   cursor to the bottom of the window. The clrtobot function acts on
   the stdscr window.

   Format

     #include  <curses.h>

     int clrtobot();

     int wclrtobot  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  [w]clrtoeol
   Erase the contents of the window from the current cursor position
   to the end of the line on the specified window. The clrtoeol
   function acts on the stdscr window.

   Format

     #include  <curses.h>

     int clrtoeol();

     int wclrtoeol  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  confstr
   Determines the current value of a specified system variable
   defined by a string value.

   Format

     #include  <unistd.h>

     size_t confstr  (int name, char *buf, size_t len);
 

3  Arguments
 

name

   The system variable setting. Valid values for the name argument
   are the _CS_X names defined in the <unistd.h> header file.
 

buf

   Pointer to the buffer where the confstr function copies the name
   value.
 

len

   The size of the buffer storing the name value.
 

3  Description
   The confstr function allows an application to determine the
   current setting of certain system parameters, limits, or options
   that are defined by a string value. The function is mainly used
   by applications to find the system default value for the PATH
   environment variable.

   If the following conditions are true, then the confstr function
   copies that value into a len-byte buffer pointed to by buf:

   o  The len argument can be 0 (zero).

   o  The name argument has a system-defined value.

   o  The buf argument is not a NULL pointer.

   If the returned string is longer than len bytes, including the
   terminating null, then the confstr function truncates the string
   to len - 1 bytes and adds a terminating null to the result. The
   application can detect that the string was truncated by comparing
   the value returned by the confstr function with the value of the
   len argument.

   The <limits.h> header file contains system-defined limits. The
   <unistd.h> header file contains system-defined environmental
   variables.

   Also, confstr supports the following three HP-UX symbolic
   constants, which are added to header file <unistd.h>:

   o  _CS_MACHINE_IDENT

   o  _CS_PARTITION_IDENT

   o  _CS_MACHINE_SERIAL
 

3  Example

     To find out how big a buffer is needed to store the string
     value of name, enter:

        confstr(_CS_PATH, NULL, (size_t) 0)

     The confstr function returns the size of the buffer necessary.
 

3  Return_Values

   0                  Indicates an error. When the specified name
                      value:

                      o  Is invalid, errno is set to EINVAL.

                      o  Does not have a system-defined value, errno
                         is not set.

   n                  The size of the buffer needed to hold the
                      value.

                      o  When the value of the name argument is
                         system-defined, confstr returns the size of
                         the buffer needed to hold the entire value.
                         If this return value is greater than the
                         len value, the string returned as the buf
                         value is truncated.

                      o  When the value of the len argument is set
                         to 0 or the buf value is NULL, confstr
                         returns the size of the buffer needed to
                         hold the entire system-defined value. The
                         string value is not copied.
 

2  conj
   Returns the complex conjugate of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex conj  (double complex z);

     float complex conjf  (float complex z);

     long double complex conjl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The conj functions return the complex conjugate of z, by
   reversing the sign of its imaginary part.
 

3  Return_Values

   x                  The complex conjugate value.
 

2  copysign
   Returns x with the same sign as y.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double copysign  (double x, double y);

     float copysignf  (float x, float y);

                      (Integrity servers, Alpha)

     long double copysignl  (long double x, long double y);

                            (Integrity servers, Alpha)
 

3  Arguments
 

x

   A real value.
 

y

   A real value.
 

3  Description
   The copysign functions return x with the same sign as y. IEEE 754
   requires copysign(x,NaN), copysignf(x,NaN), and copysignl(x,NaN)
   to return +x or -x.
 

3  Return_Value

   x                  The value of x with the same sign as y.
 

2  cos
   Returns the cosine of its radian argument.

   Format

     #include  <math.h>

     double cos  (double x);

     float cosf  (float x); (Integrity servers, Alpha)

     long double cosl  (long double x); (Integrity servers, Alpha)

     double cosd  (double x); (Integrity servers, Alpha)

     float cosdf  (float x); (Integrity servers, Alpha)

     long double cosdl  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A radian expressed as a real value.
 

3  Description
   The cos functions return the cosine of their argument, measured
   in radians.

   The cosd functions return the cosine of their argument, measured
   in degrees.

   |x| = Infinity is an invalid argument.
 

3  Return_Values

   x                  The cosine of the argument.
   HUGE_VAL           Indicates that the argument is too large;
                      errno is set to ERANGE.
 

2  cosh
   Returns the hyperbolic cosine of its radian argument.

   Format

     #include  <math.h>

     double cosh  (double x);

     float coshf  (float x); (Integrity servers, Alpha)

     long double coshl  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A radian expressed as a real number.
 

3  Description
   The cosh functions return the hyperbolic cosine of x and are
   defined as (e**x + e**(-x))/2.
 

3  Return_Values

   x                  The hyperbolic cosine of the argument.
   HUGE_VAL           Indicates that the argument is too large;
                      errno is set to ERANGE.
 

2  cot
   Returns the cotangent of its radian argument.

   Format

     #include  <math.h>

     double cot  (double x);

     float cotf  (float x); (Integrity servers, Alpha)

     long double cotl  (long double x); (Integrity servers, Alpha)

     double cotd  (double x); (Integrity servers, Alpha)

     float cotdf  (float x); (Integrity servers, Alpha)

     long double cotdl  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A radian expressed as a real number.
 

3  Description
   The cot functions return the cotangent of their argument,
   measured in radians.

   The cotd functions return the cotangent of their argument,
   measured in degrees.

   x = 0 is an invalid argument.
 

3  Return_Values

   x                  The cotangent of the argument.
   HUGE_VAL           Indicates that the argument is zero; errno is
                      set to ERANGE.
 

2  cpow
   Returns the complex power function x**y.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex cpow  (double complex x, double complex y);

     float complex cpowf  (float complex x, float complex y);

     long double complex cpowl  (long double complex x, long double complex y);
 

3  Argument
 

x

   A complex value.
 

y

   A complex value.
 

3  Description
   The cpow functions return the complex power function x**y, with a
   branch cut for the first parameter along the negative real axis.
 

3  Return_Values

   x                  The complex power function value.
 

2  cproj
   Returns a projection of its argument onto the Riemann sphere.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex cproj  (double complex z);

     float complex cprojf  (float complex z);

     long double complex cprojl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The cproj functions compute and return a projection of z onto
   the Riemann sphere: z projects to z, except that all complex
   infinities (even those with one infinite part and one NaN part)
   project to positive infinity on the real axis. If z has an
   infinite part, then cproj(z) is equivalent to:

   INFINITY + I * copysign(0.0, cimag(z))
 

3  Return_Values

   x                  The value of the projection onto the Riemann
                      sphere.
 

2  creal
   Returns the real part of its complex argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double creal  (double complex z);

     float crealf  (float complex z);

     long double creall  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The creal functions return the real part of z.
 

3  Return_Values

   x                  The real part value.
 

2  creat
   Creates a new file.

   Format

     #include  <fcntl.h>

     int creat  (const char *file_spec, mode_t mode); (ISO POSIX-1)

     int creat  (const char *file_spec, mode_t mode, . . . ); 
                                           (DEC C Extension)
 

3  Arguments
 

file_spec

   A null-terminated string containing any valid file specification.
 

mode

   An unsigned value that specifies the file-protection mode. The
   compiler performs a bitwise AND operation on the mode and the
   complement of the current protection mode.

   You can construct modes by using the bitwise OR operator (|)  to
   create mode combinations. The modes are:

   0400   OWNER:READ
   0200   OWNER:WRITE
   0100   OWNER:EXECUTE
   0040   GROUP:READ
   0020   GROUP:WRITE
   0010   GROUP:EXECUTE
   0004   WORLD:READ
   0002   WORLD:WRITE
   0001   WORLD:EXECUTE

   The system is given the same privileges as the owner. A WRITE
   privilege implies a DELETE privilege.

                                  NOTE

      To create files with OpenVMS RMS default protections using
      the UNIX system-call functions umask, mkdir, creat, and
      open, call mkdir, creat, and open with a file-protection
      mode argument of 0777 in a program that never specifically
      calls umask. These default protections include correctly
      establishing protections based on ACLs, previous versions of
      files, and so on.

      In programs that do vfork/exec calls, the new process image
      inherits whether umask has ever been called or not from
      the calling process image. The umask setting and whether
      the umask function has ever been called are both inherited
      attributes.
 

 . . .

   An optional argument list of character strings of the following
   form:

   "keyword = value", . . . ,"keyword = value"

   Or in the case of "acc" or "err", this form:

   "keyword"

   Here, keyword is an RMS field in the file access block (FAB) or
   record access block (RAB); value is valid for assignment to that
   field. Some fields permit you to specify more than one value. In
   these cases, the values are separated by commas.

   The RMS callback keywords "acc" and "err" are the only keywords
   that do not take values. Instead, they are followed by a pointer
   to the callback routine to be used, followed by a pointer to a
   user-specified value to be used as the first argument of the
   callback routine. For example, to set up an access callback
   routine called acc_callback whose first argument is a pointer
   to the integer variable first_arg in a call to open, you can use
   the following statement:

   open("file.dat", O_RDONLY, 0 ,"acc", acc_callback, &first_arg)

   The second and third arguments to the callback routine must be
   pointers to a FAB and RAB, respectively, and the routine must
   have a return type of int. If the callback returns a value less
   than 0, the open, creat, or fopen fails. The error callback can
   correct the error condition and return a status greater than
   or equal to 0 to continue the creat call. Assuming the previous
   open statement, the function prototype for acc_callback would be
   similar to the following statement:

   #include <rms.h>

   int acc_callback(int *first_arg, struct FAB *fab, struct RAB *rab);

   FAB and RAB are defined in the <rms.h> header file, and the
   actual pointers passed to the routine are pointers to the RAB
   and FAB being used to open the file file.dat.

   If an access callback routine is established, then it will be
   called in the open-type routine immediately before the call to
   the RMS function sys$create or sys$open. If an error callback
   routine is established and an error status is returned from the
   sys$create or sys$open function, then the callback routine will
   be invoked immediately after the status is checked and the error
   value is discovered.

                                  NOTE

      Any manipulation of the RAB or FAB in a callback function
      could lead to serious problems in later calls to the
      Compaq C RTL I/O functions.

   RMS Valid Keywords and Values describes the RMS keywords and
   values.

   Table REF-3 RMS Valid Keywords and Values

   Keyword        Value    Description

   "acc"          callback Access callback routine.
   "alq = n"      decimal  Allocation quantity.
   "bls = n"      decimal  Block size.
   "ctx = bin"    string   No translation of '\n' to the terminal.
                           Use this for writing binary data to
                           files.
   "ctx = cvt"    string   Negates a previous setting of
                           "ctx=nocvt". This is the default.
   "ctx =         string   No conversion of Fortran carriage-control
   nocvt"                  bytes.
   "ctx = rec"    string   Forces record mode access.
   "ctx = stm"    string   Forces stream mode access.
   "ctx =         string   Causes records to be written only when
   xplct"                  explicitly specified by a call to fflush,
                           close, or fclose.
   "deq = n"      decimal  Default extension quantity.
   "dna =         string   Default file-name string.
   filespec"
   "err"          callback Error callback routine.
   "fop = val,             File-processing options:
   val , . . . "
                  ctg      Contiguous.
                  cbt      Contiguous-best-try.
                  dfw      Deferred write; only applicable to files
                           opened for shared access.
                  dlt      Delete file on close.
                  tef      Truncate at end-of-file.
                  cif      Create if nonexistent.
                  sup      Supersede.
                  scf      Submit as command file on close.
                  spl      Spool to system printer on close.
                  tmd      Temporary delete.
                  tmp      Temporary (no file directory).
                  nef      Not end-of-file.
                  rck      Read check compare operation.
                  wck      Write check compare operation.
                  mxv      Maximize version number.
                  rwo      Rewind file on open.
                  pos      Current position.
                  rwc      Rewind file on close.
                  sqo      File can only be processed in a
                           sequential manner.
   "fsz = n"      decimal  Fixed header size.
   "gbc = n"      decimal  The requested number of global buffers
                           for a file.
   "mbc = n"      decimal  Multiblock count.
   "mbf = n"      decimal  Multibuffer count.
   "mrs = n"      decimal  Maximum record size.
   "pmt=usr-      string   Prompts for terminal input. Any RMS input
   prmpt"                  from a terminal device will be preceded
                           by "usr-prmpt" when this option and
                           "rop=pmt" are specified.
   "rat = val,             Record attributes:
   val . . . "
                  cr       Carriage-return control.
                  blk      Disallow records to span block
                  ftn      boundaries.
                  none     Fortran print control.
                  prn      Explicitly forces no carriage control.
                           Print file format.
   "rfm = val"             Record format:
                  fix      Fixed-length record format.
                  stm      RMS stream record format.
                  stmlf    Stream format with line-feed terminator.
                  stmcr    Stream format with carriage-return
                           terminator.
                  var      Variable-length record format.
                  vfc      Variable-length record with fixed
                  udf      control.
                           Undefined.
   "rop = val,             Record-processing operations:
   val . . . "
                  asy      Asynchronous I/O.
                  cco      Cancels Ctrl/O (used with Terminal I/O).
                  cvt      Capitalizes characters on a read from the
                           terminal.
                  eof      Positions the record stream to the end-
                           of-file for the connect operation only.
                  nlk      Do not lock record.
                  pmt      Enables use of the prompt specified
                           by "pmt=usr-prmpt" on input from the
                           terminal.
                  pta      Eliminates any information in the type-
                           ahead buffer on a read from the terminal.
                  rea      Locks record for a read operation for
                           this process, while allowing other
                           accessors to read the record.
                  rlk      Locks record for write.
                  rne      Suppresses echoing of input data on the
                           screen as it is entered on the keyboard.
                  rnf      Indicates that Ctrl/U, Ctrl/R, and DELETE
                           are not to be considered control commands
                           on terminal input, but are to be passed
                           to the application program.
                  rrl      Reads regardless of lock.
                  syncsts  Returns a success status of RMS$_SYNCH if
                           the requested service completes its task
                           immediately.
                  tmo      Timeout I/O.
                  tpt      Allows put/write services using
                           sequential record access mode to occur
                           at any point in the file, truncating the
                           file at that point.
                  ulk      Prohibits RMS from automatically
                           unlocking records.
                  wat      Wait until record is available, if
                           currently locked by another stream.
                  rah      Read ahead.
                  wbh      Write behind.
   "rtv=n"        decimal  The number of retrieval pointers that RMS
                           has to maintain in memory (0 to 127,255).
   "shr = val,             File sharing options:
   val, . . . "
                  del      Allows users to delete.
                  get      Allows users to read.
                  mse      Allows multistream connects.
                  nil      Prohibits file sharing.
                  put      Allows users to write.
                  upd      Allows users to update.
                  upi      Allows one or more writers.
                  nql      No query locking (file level).
   "tmo = n"      decimal  I/O timeout value.

   In addition to these options, any option that takes a key value
   (such as "fop" or "rat") can be negated by prefixing the value
   with "no". For example, specify "fop=notmp" to clear the "tmp"
   bit in the "fop" field.

                                 NOTES

      o  While these options provide much flexibility and
         functionality, many of them can also cause severe
         problems if not used correctly.

      o  You cannot share the default Compaq C for OpenVMS stream
         file I/O. If you wish to share files, you must specify
         "ctx=rec" to force record access mode. You must also
         specify the appropriate "shr" options depending on the
         type of access you want.

      o  If you intend to share a file opened for append, you must
         specify appropriate share and record-locking options, to
         allow other accessors to read the record. The reason for
         doing this: the file is positioned at the end-of-file by
         reading records in a loop until end-of-file is reached.

   For more information on these options, see the OpenVMS Record
   Management Services Reference Manual.
 

3  Description
   The Compaq C RTL opens the new file for reading and writing, and
   returns the corresponding file descriptor.

   If the file exists:

   o  A version number one greater than any existing version is
      assigned to the newly created file.

   o  By default, the new file inherits certain attributes from
      the existing version of the file unless those attributes are
      specified in the creat call. The following attributes are
      inherited:

      -  Record format (FAB$B_RFM)

      -  Maximum record size (FAB$W_MRS)

      -  Carriage control (FAB$B_RAT)

      -  File protection

   o  When a new version of a file is created, and the named file
      already exists as a symbolic link, the file to which the
      symbolic link refers is created.

   If the file did not previously exist:

   o  It is given the file protection that results from performing
      a bitwise AND on the mode argument and the complement of the
      current protection mask.

   o  It defaults to stream format with line-feed record separator
      and implied carriage-return attributes.

   See also open, close, read, write, and lseek in this section.
 

3  Return_Values

   n                  A file descriptor.
   -1                 Indicates errors, including protection
                      violations, undefined directories, and
                      conflicting file attributes.
 

2  [no]crmode
   In the UNIX system environment, the crmode and nocrmode functions
   set and unset the terminal from cbreak mode. In cbreak mode, a
   single input character can be processed without pressing Return.
   This mode of single-character input is only supported with the
   Curses input routine getch.

   Format

     #include  <curses.h>

     crmode()

     nocrmode()
 

3  Example

       /* Program to demonstrate the use of crmod() and curses */

       #include <curses.h>

       main()
       {
           WINDOW *win1;
           char vert = '.',
                hor = '.',
                str[80];

           /*  Initialize standard screen, turn echo off.  */
           initscr();
           noecho();

           /*  Define a user window.  */
           win1 = newwin(22, 78, 1, 1);

           /*  Turn on reverse video and draw a box on border.  */
           setattr(_REVERSE);
           box(stdscr, vert, hor);
           mvwaddstr(win1, 2, 2, "Test cbreak input");
           refresh();
           wrefresh(win1);

           /*  Set cbreak, do some input, and output it.  */
           crmode();
           getch();
           nocrmode(); /* Turn off cbreak. */
           mvwaddstr(win1, 5, 5, str);
           mvwaddstr(win1, 7, 7, "Type something to clear the screen");
           wrefresh(win1);

           /*  Get another character, then delete the window.  */
           getch();
           wclear(win1);
           touchwin(stdscr);
           endwin();
       }

     In this example, the first call to getch returns as soon as one
     character is entered, because crmode was called before getch
     was called. The second time getch is called, it waits until the
     Return key is pressed before processing the character entered,
     because nocrmode was called before getch was called the second
     time.
 

2  crypt
   The password encryption function.

   Format

     #include  <unistd.h>

     #include  <stdlib.h>

     char *crypt  (const char *key, const char *salt;)
 

3  Function_Variants
   The crypt function has variants named _crypt32 and _crypt64 for
   use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Argument
 

key

   A user's typed password.
 

salt

   A 2-character string.
 

3  Description
   The crypt function generates an encoded version of a password.
   It is based on the NBS Data Encryption Standard, with variations
   intended to frustrate use of hardware implementations of the DES
   for key search.

   The first argument to crypt is normally a user's typed password.
   The second is a 2-character string chosen from the set [a-zA-Z0-
   9./]. The salt string is used to perturb the DES algorithm in one
   of 4096 different ways, after which the password is used as the
   key to encrypt repeatedly a constant string. The returned value
   points to the encrypted password, in the same alphabet as the
   salt. The first two characters are the salt itself.

   The return value from crypt points to a static data area whose
   content is overwritten by each call.

   See also encrypt and setkey.
 

3  Return_Value

   pointer            Pointer to the encrypted password.
 

2  csin
   Returns the complex sine of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex csin  (double complex z);

     float complex csinf  (float complex z);

     long double complex csinl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The csin functions compute the complex sine value of z.
 

3  Return_Values

   x                  The complex sine value.

   Returns the complex hyperbolic sine of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex csinh  (double complex z);

     float complex csinhf  (float complex z);

     long double complex csinhl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The csinh functions compute the complex hyperbolic sine of z.
 

3  Return_Values

   x                  The complex hyperbolic sine value.
 

2  csqrt
   Returns the complex square root of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex csqrt  (double complex z);

     float complex csqrtf  (float complex z);

     long double complex csqrtl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The csqrt functions compute the complex square root of z, with a
   branch cut along the negative real axis.
 

3  Return_Values

   x                  The complex square root value in the range of
                      the right half-plane (including the imaginary
                      axis).
 

2  ctan
   Returns the complex tangent of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex ctan  (double complex z);

     float complex ctanf  (float complex z);

     long double complex ctanl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The ctan functions compute the complex tangent value of z.
 

3  Return_Values

   x                  The complex tangent value.
 

2  ctanh
   Returns the complex hyperbolic tangent of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <complex.h>

     double complex ctanh  (double complex z);

     float complex ctanhf  (float complex z);

     long double complex ctanhl  (long double complex z);
 

3  Argument
 

z

   A complex value.
 

3  Description
   The ctanh functions compute the complex hyperbolic tangent value
   of z.
 

3  Return_Values

   x                  The complex hyperbolic tangent value.
 

2  ctermid
   Returns a character string giving the equivalence string of
   SYS$COMMAND. This is the name of the controlling terminal.

   Format

     #include  <stdio.h>

     char *ctermid  (char *str);
 

3  Function_Variants
   The ctermid function has variants named _ctermid32 and _ctermid64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Argument
 

str

   Must be a pointer to an array of characters. If this argument is
   NULL, the filename is stored internally and might be overwritten
   by the next ctermid call. Otherwise, the filename is stored
   beginning at the location indicated by the argument. The argument
   must point to a storage area of length L_ctermid (defined by the
   <stdio.h> header file).
 

3  Return_Value

   pointer            Points to a character string.
 

2  ctime
   Converts a time in seconds, since 00:00:00 January 1, 1970, to an
   ASCII string in the form generated by the asctime function.

   Format

     #include  <time.h>

     char *ctime  (const time_t *bintim);

     char *ctime_r  (const time_t *bintim, char *buffer); 
                          (ISO POSIX-1)                                    

3  Function_Variants
   Compiling with the _DECC_V4_SOURCE and _VMS_V6_SOURCE feature-
   test macros defined enables a local-time-based entry point to
   this function that is equivalent to the behavior before OpenVMS
   Version 7.0.
 

3  Arguments
 

bintim

   A pointer to a variable that specifies the time value (in
   seconds) to be converted.
 

buffer

   A pointer to a character array that is at least 26 bytes long.
   This array is used to store the generated date-and-time string.
 

3  Description
   The ctime and ctime_r functions convert the time pointed to by
   bintim into a 26-character string, and return a pointer to the
   string.

   The difference between the ctime_r and ctime functions is that
   the former puts its result into a user-specified buffer. The
   latter puts its result into thread-specific static memory
   allocated by the Compaq C RTL, which can be overwritten by
   subsequent calls to ctime or asctime; you must make a copy if
   you want to save it.

   On success, ctime returns a pointer to the string; ctime_r
   returns its second argument. On failure, these functions return
   the NULL pointer.

   The type time_t is defined in the <time.h> header file as
   follows:

   typedef long int time_t

   The ctime function behaves as if it called tzset.

                                  NOTE

      Generally speaking, UTC-based time functions can affect in-
      memory time-zone information, which is processwide data.
      However, if the system time zone remains the same during
      the execution of the application (which is the common case)
      and the cache of timezone files is enabled (which is the
      default), then the _r variant of the time functions asctime_
      r, ctime_r, gmtime_r, and localtime_r, is both thread-safe
      and AST-reentrant.

      If, however, the system time zone can change during the
      execution of the application or the cache of timezone files
      is not enabled, then both variants of the UTC-based time
      functions belong to the third class of functions, which are
      neither thread-safe nor AST-reentrant.
 

3  Return_Values

   x                  A pointer to the 26-character ASCII string, if
                      successful.
   NULL               Indicates failure.
 

2  cuserid
   Returns a pointer to a character string containing the name of
   the user initiating the current process.

   Format

     #include  <unistd.h> (X/Open, POSIX-1)

     #include  <stdio.h> (X/Open)

     char *cuserid  (char *str);
 

3  Function_Variants
   The cuserid function has variants named _cuserid32 and _cuserid64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Argument
 

str

   If this argument is NULL, the user name is stored internally. If
   the argument is not NULL, it points to a storage area of length
   L_cuserid (defined by the <stdio.h> header file), and the name is
   written into that storage. If the user name is a null string, the
   function returns NULL.
 

3  Return_Values

   pointer            Points to a string.
   NULL               If the user name is a null string.
 

2  DECC$CRTL_INIT
   Allows you to call the Compaq C RTL from other languages or to
   use the Compaq C RTL when your main function is not in C. It
   initializes the run-time environment and establishes both an exit
   and condition handler. VAXC$CRTL_INIT is a synonym for DECC$CRTL_
   INIT. Either name invokes the same routine.

   Format

     #include  <signal.h>

     void DECC$CRTL_INIT(void);
 

3  Description
   The following example shows a Pascal program that calls the
   Compaq C RTL using the DECC$CRTL_INIT function:

   $ PASCAL EXAMPLE1
   $ LINK EXAMPLE1
   $ TY EXAMPLE1.PAS
   PROGRAM TESTC(input, output);
   PROCEDURE DECC$CRTL_INIT; extern;
   BEGIN
      DECC$CRTL_INIT;
   END

   A shareable image need only call this function if it contains
   an Compaq C function for signal handling, environment variables,
   I/O, exit handling, a default file protection mask, or if it is a
   child process that should inherit context.

   Although many of the initialization activities are performed only
   once, DECC$CRTL_INIT can safely be called multiple times.

   At least one frame in the current call stack must have that
   handler established for OpenVMS exceptions to get mapped to UNIX
   signals.
 

2  decc$feature_get
   Calls decc$feature_get_value with a character-string feature
   name, rather than an index.

   Format

     #include  <unixlib.h>

     int decc$feature_get  (const char *name, int mode);
 

3  Argument
 

name

   Pointer to a character string passed as a name in the list of
   supported features.
 

mode

   An integer indicating which feature value to return. The values
   for mode are:

      __FEATURE_MODE_DEFVAL        Default value
      __FEATURE_MODE_CURVAL        Current value
      __FEATURE_MODE_MINVAL        Minimum value
      __FEATURE_MODE_MAXVAL        Maximum value
      __FEATURE_MODE_INIT_STATE    Initialization state
 

3  Description
   The decc$feature_get function allows you to call the
   decc$feature_get_value function with a character-string feature
   name, rather than an index into an internal C RTL table.

   On error, -1 is returned and errno is set to indicate the error.

   See also decc$feature_get_value, decc$feature_get_index,
   decc$feature_get_name, decc$feature_set, decc$feature_set_value,
   decc$feature_show, and decc$feature_show_all.
 

3  Return_Values

   n                  An integer corresponding to the specified name
                      and mode arguments.
   -1                 Indicates an error; errno is set.
 

2  decc$feature_get_index
   Returns an index for accessing feature values.

   Format

     #include  <unixlib.h>

     int decc$feature_get_index  (char *name);
 

3  Argument
 

name

   Pointer to a character string passed as a name in the list of
   supported features.
 

3  Description
   The decc$feature_get_index function looks up the string passed
   as name in the list of supported features. If the name is found,
   decc$feature_get_index returns a (nonnegative) index that can
   be used to set or retrieve the values for the feature. The
   comparison for name is case insensitive.

   On error, -1 is returned and errno is set to indicate the error.

   See also decc$feature_get, decc$feature_get_value, decc$feature_
   get_name, decc$feature_set, decc$feature_set_value, decc$feature_
   show, and decc$feature_show_all.
 

3  Return_Values

   n                  A nonnegative index that can be used to set or
                      retrieve the specified values for the feature.
   -1                 Indicates an error; errno is set.
 

2  decc$feature_get_name
   Returns a feature name.

   Format

     #include  <unixlib.h>

     char *decc$feature_get_name  (int index);
 

3  Argument
 

index

   An integer value from 0 to the highest allocated feature.
 

3  Description
   The decc$feature_get_name function returns a pointer to a null-
   terminated string containing the name of the feature for the
   entry specified by index. The index value can be 0 to the highest
   allocated feature. If there is no feature corresponding to the
   index value, then the function returns a NULL pointer.

   On error, NULL is returned and errno is set to indicate the
   error.

   See also decc$feature_get, decc$feature_get_index, decc$feature_
   get_value, decc$feature_set, decc$feature_set_value,
   decc$feature_show, and decc$feature_show_all.
 

3  Return_Values

   x                  Pointer to a null-terminated string containing
                      the name of the feature for the entry
                      specified by index.
   NULL               Indicates an error; errno is set.
 

2  decc$feature_get_value
   Returns a feature value specified by the index and mode
   arguments.

   Format

     #include  <unixlib.h>

     int decc$feature_get_value  (int index, int mode);
 

3  Arguments
 

index

   An integer value from 0 to the highest allocated feature.
 

mode

   An integer indicating which feature value to return. The values
   for mode are:

      __FEATURE_MODE_DEFVAL        Default value
      __FEATURE_MODE_CURVAL        Current value
      __FEATURE_MODE_MINVAL        Minimum value
      __FEATURE_MODE_MAXVAL        Maximum value
      __FEATURE_MODE_INIT_STATE    Initialization state
 

3  Description
   The decc$feature_get_value function retrieves a value for the
   feature specified by index. The mode determines which value is
   returned.

   The default value is what is used if not set by a logical name or
   overridden by a call to decc$feature_set_value.

   If mode = 4, then the initialization state is returned. Values
   for the initialization state are:

      0 not initialized
      1 set by logical name
      2 forced by decc$feature_set_value
      -1-initialized to default value

   On error, -1 is returned and errno is set to indicate the error.

   See also decc$feature_get, decc$feature_get_index, decc$feature_
   get_name, decc$feature_set, decc$feature_set_value, decc$feature_
   show, and decc$feature_show_all.
 

3  Return_Values

   n                  An integer corresponding to the specified
                      index and mode arguments.
   -1                 Indicates an error; errno is set.
 

2  decc$feature_set
   Calls decc$feature_set_value with a character-string feature
   name, rather than an index.

   Format

     #include  <unixlib.h>

     int decc$feature_set  (const char *name, int mode, int value);
 

3  Argument
 

name

   Pointer to a character string passed as a name in the list of
   supported features.
 

mode

   An integer indicating which feature value to return. The values
   for mode are:

      __FEATURE_MODE_DEFVAL        Default value
      __FEATURE_MODE_CURVAL        Current value
      __FEATURE_MODE_MINVAL        Minimum value
      __FEATURE_MODE_MAXVAL        Maximum value
      __FEATURE_MODE_INIT_STATE    Initialization state
 

value

   The feature value to be set.
 

3  Description
   The decc$feature_set function allows you to call the
   decc$feature_set_value function with a character-string feature
   name, rather than an index into an internal C RTL table.

   If successful, the function returns the previous value.

   On error, -1 is returned and errno is set to indicate the error.

   See also decc$feature_set_value, decc$feature_get, decc$feature_
   get_index, decc$feature_get_name, decc$feature_get_value.
   decc$feature_show, and decc$feature_show_all.
 

3  Return_Values

   n                  The previous feature value.
   -1                 Indicates an error; errno is set.
 

2  decc$feature_set_value
   Sets the default value or the current value for the feature
   specified by index.

   Format

     #include  <unixlib.h>

     int decc$feature_set_value  (int index, int mode, int value);
 

3  Arguments
 

index

   An integer value from 0 to the highest allocated feature.
 

mode

   An integer indicating whether to set the default or current
   feature value. The values for mode are:

      0 default value
      1 current value
 

value

   The feature value to be set.
 

3  Description
   The decc$feature_set_value function sets the default value or
   the current value (as determined by the mode argument) for the
   feature specified by index.

   If this function is successful, it returns the previous value.

   On error, -1 is returned and errno is set to indicate the error.

   See also decc$feature_get, decc$feature_get_index, decc$feature_
   get_name, decc$feature_get_value, decc$feature_set, decc$feature_
   show, and decc$feature_show_all.
 

3  Return_Values

   n                  The previous feature value.
   -1                 Indicates an error; errno is set.
 

2  decc$feature_show
   Displays all feature values for the specified feature name.

   Format

     #include  <unixlib.h>

     int decc$feature_show  (const char *name);
 

3  Argument
 

name

   Pointer to a character string passed as a name in the list of
   supported features.
 

3  Description
   The decc$feature_show function displays to stdout all values for
   the specified feature name. For example:

   --------- C RTL Feature Name ---------   Cur  Def  Min  Max  Ini

   DECC$V62_RECORD_GENERATION                0    0    0    1    -1

   On error, -1 is returned and errno is set to indicate the error.

   See also decc$feature_get, decc$feature_get_index, decc$feature_
   get_name, decc$feature_get_value, decc$feature_set, decc$feature_
   set_value, and decc$feature_show_all.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set.
 

2  decc$feature_show_all
   Displays all feature values for all feature names.

   Format

     #include  <unixlib.h>

     int decc$feature_show_all  (void);
 

3  Description
   The decc$feature_show_all function displays to stdout all values
   for all feature names.

   On error, -1 is returned and errno is set to indicate the error.

   See also decc$feature_get, decc$feature_get_index, decc$feature_
   get_name, decc$feature_get_value, decc$feature_set, decc$feature_
   set_value, and decc$feature_show.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set.
 

2  decc$fix_time
   Converts OpenVMS binary system times to UNIX binary times.

   Format

     #include  <unixlib.h>

     unsigned int decc$fix_time  (void *vms_time);
 

3  Argument
 

vms_time

   The address of a quadword containing an OpenVMS binary time:

   unsigned int quadword[2];
   unsigned int *vms_time = quadword;
 

3  Description
   The decc$fix_time routine converts an OpenVMS binary system time
   (a 64-bit quadword containing the number of 100-nanosecond ticks
   since 00:00 November 17, 1858) to a UNIX binary time (a longword
   containing the number of seconds since 00:00 January 1, 1970).
   This routine is useful for converting binary times returned by
   OpenVMS system services and RMS services to the format used by
   some Compaq C RTL routines, such as ctime and localtime.
 

3  Return_Values

   x                  A longword containing the number of seconds
                      since 00:00 January 1, 1970.
   (unsigned          Indicates an error. Be aware, that a return
   int)(-1)           value of (unsigned int)(-1) can also represent
                      a valid date of Sun Feb 7 06:28:15 2106.
 

3  Example

       #include <unixlib.h>
       #include <stdio.h>
       #include <starlet.h>  /* OpenVMS specific SYS$ routines)  */

       main()
       {
       unsigned int current_vms_time[2];
       /*quadword for OpenVMS time*/
       unsigned int number_of_seconds;   /* number of seconds     */

       /* first get the current system time */
       sys$gettim(&current_vms_time[0]);

       /* fix the time */
       number_of_seconds = decc$fix_time(&current_vms_time[0]);

       printf("Number of seconds since 00:00 January 1, 1970 = %d",
               number_of_seconds);
       }

     This example shows how to use the decc$fix_time routine in
     Compaq C. It also shows the use of the SYS$GETTIM system
     service.
 

2  decc$from_vms
   Converts OpenVMS file specifications to UNIX style file
   specifications.

   Format

     #include  <unixlib.h>

     int decc$from_vms  (const char *vms_filespec, int
                        action_routine, int wild_flag);
 

3  Arguments
 

vms_filespec

   The address of a null-terminated string containing a name in
   OpenVMS file specification format.
 

action_routine

   The address of a routine that takes as its only argument a null-
   terminated string containing the translation of the given OpenVMS
   filename to a valid UNIX style filename.

   If the action_routine returns a nonzero value (TRUE), file
   translation continues. If it returns a zero value (FALSE), no
   further file translation takes place.
 

wild_flag

   Either 0 or 1, passed by value. If a 0 is specified, wildcards
   found in vms_filespec are not expanded. Otherwise, wildcards
   are expanded and each one is passed to action_routine. Only
   expanded filenames that correspond to existing UNIX style files
   are included.
 

3  Description
   The decc$from_vms routine converts the given OpenVMS file
   specification into the equivalent UNIX style file specification.
   It allows you to specify OpenVMS wildcards, which are translated
   into a list of corresponding existing files in UNIX style file
   specification format.
 

3  Return_Value

   x                  The number of filenames that result from the
                      specified OpenVMS file specification.
 

3  Example

       /* This example must be run as a foreign command        */
       /* and be supplied with an OpenVMS file specification.  */

       #include <unixlib.h>
       #include <stdio.h>

       int main(int argc, char *argv[])
       {
           int number_found;           /* number of files found */
           int print_name();           /* name printer          */

           printf("Translating: %s\n", argv[1]);
           number_found = decc$from_vms(argv[1], print_name, 1);
           printf("\n%d files found", number_found);
       }

       /* print the name on each line */
       print_name(char *name)
       {
           printf("\n%s", name);
           /* will continue as long as success status is returned */
           return (1);
       }

     This example shows how to use the decc$from_vms routine in
     Compaq C. It produces a simple form of the ls command that
     lists existing files that match an OpenVMS file specification
     supplied on the command line. The matching files are displayed
     in UNIX style file specification format.
 

2  decc$match_wild
   Matches a string to a pattern.

   Format

     #include  <unixlib.h>

     int decc$match_wild  (char *test_string, char *string_pattern);
 

3  Arguments
 

test_string

   The address of a null-terminated string.
 

string_pattern

   The address of a string containing the pattern to be matched.
   This pattern can contain wildcards (such as asterisks (*),
   question marks (?),  and percent signs (%) as well as regular
   expressions (such as the range [a-z]).
 

3  Description
   The decc$match_wild routine determines whether the specified
   test string is a member of the set of strings specified by the
   pattern.
 

3  Return_Values

   1 (TRUE)           The string matches the pattern.
   0 (FALSE)          The string does not match the pattern.
 

3  Example

       /* Define as a foreign command and then provide */
       /* two arguments: test_string, string_pattern.  */

       #include <unixlib.h>
       #include <stdio.h>
       int main(int argc, char *argv[])
       {
           if (decc$match_wild(argv[1], argv[2]))
               printf("\n%s matches %s", argv[1], argv[2]);
           else
               printf("\n%s does not match %s", argv[1], argv[2]);
       }
 

2  decc$record_read
   Reads a record from a file.

   Format

     #include  <stdio.h>

     int decc$record_read  (FILE *fp, void *buffer, int nbytes);
 

3  Arguments
 

fp

   A file pointer. The specified file pointer must refer to a file
   currently opened for reading.
 

buffer

   The address of contiguous storage in which the input data is
   placed.
 

nbytes

   The maximum number of bytes involved in the read operation.
 

3  Description
   The decc$record_read function is specific to OpenVMS systems and
   should not be used when writing portable applications.

   This function is equivalent to the read function, except that the
   first argument is a file pointer, not a file descriptor.
 

3  Return_Values

   x                  The number of characters read.
   -1                 Indicates a read error, including physical
                      input errors, illegal buffer addresses,
                      protection violations, undefined file
                      descriptors, and so forth.
 

2  decc$record_write
   Writes a record to a file.

   Format

     #include  <stdio.h>

     int decc$record_write  (FILE *fp, void *buffer, int nbytes);
 

3  Arguments
 

fp

   A file pointer. The specified file pointer must refer to a file
   currently opened for writing or updating.
 

buffer

   The address of contiguous storage from which the output data is
   taken.
 

nbytes

   The maximum number of bytes involved in the write operation.
 

3  Description
   The decc$record_write function is specific to OpenVMS systems and
   should not be used when writing portable applications.

   This function is equivalent to the write function, except that
   the first argument is a file pointer, not a file descriptor.
 

3  Return_Values

   x                  The number of bytes written.
   -1                 Indicates errors, including undefined file
                      descriptors, illegal buffer addresses, and
                      physical I/O errors.
 

2  decc$set_child_default_dir
   Sets the default directory for a child process spawned by a
   function from the exec family of functions.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unixlib.h>

     int decc$set_child_default_dir  (const char *default_dir);
 

3  Arguments
 

default_dir

   The default directory specification for child processes, or NULL.
 

3  Description
   By default, child processes created by one of the exec family of
   functions inherit the default (working) directory of their parent
   process.

   The decc$set_child_default_dir function lets you set the
   default directory for a child process. After calling decc$set_
   child_default_dir, newly spawned child processes have their
   default directory set to default_dir as they begin execution.
   The default_dir argument must represent a valid directory
   specification, or results of the call are unpredictable
   (subsequent calls to the child process might fail without
   notification). Both OpenVMS and UNIX style file specifications
   are supported for this function call.

   You can reestablish the default behavior by specifying default_
   dir as NULL. Subsequently, newly created child processes will
   inherit their parent's working directory.
 

3  Return_Values

   0                  Successful completion. The new inherited
                      default directory was established.
   -1                 Indicates failure. No new default directory
                      was established for child processes. The
                      function sets errno to one of the following
                      values:

                      o  ENOMEM - Insufficient memory

                      o  ENAMETOOLONG - default_dir is too long to
                         issue the required SET DEFAULT command.
 

2  decc$set_child_standard_streams
   For a child spawned by a function from the exec family of
   functions, associates specified file descriptors with a child's
   standard streams: stdin, stdout, and stderr.

   Format

     #include  <unixlib.h>

     int decc$set_child_standard_streams  (int fd1, int fd2, int fd3);
 

3  Arguments
 

fd1

   The file associated with this file descriptor in the parent
   process is associated with file descriptor number 0 (stdin) in
   the child process. If -1 is specified, the file associated with
   the parent's file descriptor number 0 is used (the default).
 

fd2

   The file associated with this file descriptor in the parent
   process is associated with file descriptor number 1 (stdout) in
   the child process. If -1 is specified, the file associated with
   the parent's file descriptor number 1 is used (the default).
 

fd3

   The file associated with this file descriptor in the parent
   process is associated with file descriptor number 2 (stderr) in
   the child process. If -1 is specified, the file associated with
   the parent's file descriptor number 2 is used (the default).
 

3  Description
   The decc$set_child_standard_streams function allows mapping of
   specified file descriptors to the child's stdin/stdout/stderr
   streams, thereby compensating, to a certain degree, the lack of a
   real fork function on OpenVMS systems.

   On UNIX systems, the code between fork and exec is executed in
   the context of the child process:

   parent:
     create pipes p1, p2 and p3
     fork
   child:

     map stdin to p1  like dup2(p1, stdin);
     map stdout to p2 like dup2(p2, stdout);
     map stderr to p3 like dup2(p3, stderr);

     exec (child reads from stdin and writes to stdout and stderr)
     exit
   parent:
     communicates with the child using pipes

   On OpenVMS systems, the same task could be achieved as follows:

   parent:
     create pipes p1, p2 and p3
     decc$set_child_standard_streams(p1, p2, p3);
     vfork
     exec (child reads from stdin and writes to stdout and stderr)
   parent:
     communicates with the child using pipes

   Once established through the call to decc$set_child_standard_
   streams, the mapping of the child's standard streams remains in
   effect until explicitly disabled by one of the following calls:

   decc$set_child_standard_streams(-1, -1, -1);

   Or:

   decc$set_child_standard_streams(0, 1, 2);

   Usually, the child process inherits all its parent's open file
   descriptors. However, if file descriptor number n was specified
   in the call to decc$set_child_standard_streams, it is not
   inherited by the child process as file descriptor number n;
   instead, it becomes one of the child's standard streams.

                                 NOTES

      o  Standard streams can be redirected only to pipes.

      o  If the parent process redefines the DCL DEFINE command,
         this redefinition is not in effect in a subprocess with
         user-defined channels. The subprocess always sees the
         standard DCL DEFINE command.

      o  It is the responsibility of the parent process to consume
         all the output written by the child process to stdout and
         stderr. Depending on how the subprocess writes to stdout
         and stderr-in wait or nowait mode-the subprocess might be
         placed in LEF state waiting for the reader. For example,
         DCL writes to SYS$OUTPUT and SYS$ERROR in a wait mode,
         so a child process executing a DCL command procedure will
         wait until all the output is read by the parent process.

         Recommendation: Read the pipes associated with the child
         process' stdout and stderr in a loop until an EOF message
         is received, or declare write attention ASTs on these
         mailboxes.

      o  The amount of data written to SYS$OUTPUT depends on the
         verification status of the process (SET VERIFY/NOVERIFY
         command); the subprocess inherits the verification status
         of the parent process. It is the caller's responsibility
         to set the verification status of the parent process to
         match the expected amount of data written to SYS$OUTPUT
         by the subprocess.

      o  Some applications, like DTM, define SYS$ERROR as
         SYS$OUTPUT. If stderr is not redefined by the caller,
         it is set in the subprocess as the parent's SYS$ERROR,
         which in this case translates to the parent's SYS$OUTPUT.

         If the caller redefines stdout to a pipe and does not
         redefine stderr, output sent to stderr goes to the pipe
         associated with stdout, and the amount of data written
         to this mailbox may be more than expected. Although
         redefinition of any subset of standard channels is
         supported, it is always safe to explicitly redefine all
         of them (or at least stdout and stderr) to avoid this
         situation.

      o  For a child process executing a DCL command procedure,
         SYS$COMMAND is set to the pipe specified for the child's
         stdin so that the parent process can feed the child
         requesting data from SYS$COMMAND through the pipe. For
         DCL command procedures, it is impossible to pass data
         from the parent to the child by means of the child's
         SYS$INPUT because for a command procedure, DCL defines
         SYS$INPUT as the command file itself.
 

3  Return_Values

   x                  The number of file descriptors set for the
                      child. This number does not include file
                      descriptors specified as -1 in the call.
   -1                 indicates that an invalid file descriptor was
                      specified; errno is set to EBADF.
 

3  Example

       parent.c
       ========

       #include <stdio.h>
       #include <string.h>
       #include <unistd.h>

       int decc$set_child_standard_streams(int, int, int);

       main()
       {
           int fdin[2], fdout[2], fderr[2];
           char msg[] = "parent writing to child's stdin";
           char buf[80];
           int nbytes;

           pipe(fdin);
           pipe(fdout);
           pipe(fderr);

           if ( vfork() == 0 ) {
          decc$set_child_standard_streams(fdin[0], fdout[1], fderr[1]);
             execl( "child", "child" );
           }
           else {
               write(fdin[1], msg, sizeof(msg));
               nbytes = read(fdout[0], buf, sizeof(buf));
               buf[nbytes] = '\0';
               puts(buf);
               nbytes = read(fderr[0], buf, sizeof(buf));
               buf[nbytes] = '\0';
               puts(buf);
           }
       }

       child.c
       =======

       #include <stdio.h>
       #include <unistd.h>

       main()
       {
           char msg[] = "child writing to stderr";
           char buf[80];
           int nbytes;

           nbytes = read(0, buf, sizeof(buf));
           write(1, buf, nbytes);
           write(2, msg, sizeof(msg));
       }

       child.com
       =========

       $ read sys$command s
       $ write sys$output s
       $ write sys$error "child writing to stderr"

     This example program returns the following for both child.c and
     child.com:

       $ run parent
       parent writing to child's stdin
       child writing to stderr

     Note that in order to activate child.com, you must explicitly
     specify execl("child.com", ...) in the parent.c program.
 

2  decc$set_reentrancy
   Controls the type of reentrancy that reentrant Compaq C RTL
   routines will exhibit.

   Format

     #include  <reentrancy.h>

     int decc$set_reentrancy  (int type);
 

3  Argument
 

type

   The type of reentrancy desired. Use one of the following values:

   o  C$C_MULTITHREAD - Designed to be used in conjunction with the
      DECthreads product. It performs DECthreads locking and never
      disables ASTs. DECthreads must be available on your system to
      use this form of reentrancy.

   o  C$C_AST - Uses the __TESTBITSSI (Integrity servers, Alpha)
      built-in function to perform simple locking around critical
      sections of RTL code, and it may additionally disable
      asynchronous system traps (ASTs) in locked regions of
      code. This type of locking should be used when AST code
      contains calls to Compaq C RTL I/O routines, or when the user
      application disables ASTs.

   o  C$C_TOLERANT - Uses the
      __TESTBITSSI (Integrity servers, Alpha)  built-in function
      to perform simple locking around critical sections of RTL
      code, but ASTs are not disabled. This type of locking should
      be used when ASTs are used and must be delivered immediately.
      TOLERANT is the default reentrancy type.

   o  C$C_NONE - Gives optimal performance in the Compaq C RTL, but
      does absolutely no locking around critical sections of RTL
      code. It should only be used in a single-threaded environment
      when there is no chance that the thread of execution will be
      interrupted by an AST that would call the Compaq C RTL.

   The reentrancy type can be raised but never lowered. The ordering
   of reentrancy types from low to high is C$C_NONE, C$C_TOLERANT,
   C$C_AST and C$C_MULTITHREAD. For example, once an application
   is set to multithread, a call to set the reentrancy to AST is
   ignored. A call to decc$set_reentrancy that attempts to lower the
   reentrancy type returns a value of -1.
 

3  Description
   Use the decc$set_reentrancy function to change the type of
   reentrancy exhibited by reentrant routines.

   decc$set_reentrancy must be called exclusively at the non-AST
   level.

   In an application using DECthreads, DECthreads automatically sets
   the reentrancy to multithread.
 

3  Return_Value

   type               The type of reentrancy used before this call.
   -1                 The reentrancy was set to a lower type.
 

2  decc$to_vms
   Converts UNIX style file specifications to OpenVMS file
   specifications.

   Format

     #include  <unixlib.h>

     int decc$to_vms  (const char *unix_style_filespec, 
                      int (*action_routine)
                      (char *OpenVMS_style_filespec, int type_of_file),
                      int allow_wild, int no_directory);
 

3  Arguments
 

unix_style_filespec

   The address of a null-terminated string containing a name in UNIX
   style file specification format.
 

action_routine

   The address of a routine called by decc$to_vms that accepts the
   following arguments:

   o  A pointer to a null-terminated string that is the result of
      the translation to OpenVMS format.

   o  An integer that has one of the following values:

      Value               Translation

      0 (DECC$K_FOREIGN)  A file on a remote system that is not
                          running the OpenVMS or VAXELN operating
                          system.
      1 (DECC$K_FILE)     The translation is a file.
      2 (DECC$K_          The OpenVMS translation of the UNIX style
      DIRECTORY)          filename is a directory.

      These values can be defined symbolically with the symbols
      DECC$K_FOREIGN, DECC$K_FILE, and DECC$K_DIRECTORY. See the
      example for more information.

   If action_routine returns a nonzero value (TRUE), file
   translation continues. If it returns a 0 value (FALSE), no
   further file translation takes place.
 

allow_wild

   Either 0 or 1, passed by value. If a 0 is specified, wildcards
   found in unix_style_filespec are not expanded. Otherwise,
   wildcards are expanded and each one is passed to action_routine.
   Only expanded filenames that correspond to existing OpenVMS files
   are included.
 

no_directory

   An integer that has one of the following values:
 

   Value            Translation

   0                Directory allowed.
   1                Prevent expansion of the string as a directory
                    name.
   2                Forced to be a directory name.
 

3  Description
   The decc$to_vms function converts the given UNIX style file
   specification into the equivalent OpenVMS file specification
   (in all uppercase letters). It allows you to specify UNIX style
   wildcards, which are translated into a list of corresponding
   OpenVMS files.

   Note that the following feature logicals can affect the behavior
   of decc$to_vms:

      DECC$DISABLE_TO_VMS_LOGNAME_TRANSLATION
      DECC$NO_ROOTED_SEARCH_LISTS
 

3  Return_Value

   x                  The number of filenames that result from the
                      specified UNIX style file specification.
 

3  Example

       /* Translate "UNIX" wildcard file names to OpenVMS names.*/
       /* Define as a foreign command and provide the name as   */
       /* an argument.                                          */

       #include <unixlib.h>
       #include <stdio.h>
       int print_name(char *, int);
       int main(int argc, char *argv[])
       {
           int number_found;           /* number of files found */

           printf("Translating: %s\n", argv[1]);

           number_found = decc$to_vms(argv[1], print_name, 1, 0);
           printf("%d files found\n", number_found);
       }

       /* action routine that prints name and type on each line */

       int print_name(char *name, int type)
       {
           if (type == DECC$K_DIRECTORY)
               printf("directory: %s\n", name);
           else if (type == DECC$K_FOREIGN)
               printf("remote non-VMS: %s\n", name);
           else
               printf("file:        %s\n", name);

       /* Translation continues as long as success status is returned */
           return (1);
       }

     This example shows how to use the decc$to_vms routine in
     Compaq C. It takes a UNIX style file specification argument
     and displays, in OpenVMS file specification format, the name of
     each existing file that matches it.
 

2  decc$translate_vms
   Translates OpenVMS file specifications to UNIX style file
   specifications.

   Format

     #include  <unixlib.h>

     char *decc$translate_vms  (const char *vms_filespec);
 

3  Argument
 

vms_filespec

   The address of a null-terminated string containing a name in
   OpenVMS file specification format.
 

3  Description
   The decc$translate_vms function translates the given OpenVMS file
   specification into the equivalent UNIX style file specification,
   whether or not the file exists. The translated name string is
   stored in a thread-specific memory, which is overwritten by each
   call to decc$translate_vms from the same thread.

   This function differs from the decc$from_vms function, which does
   the conversion for existing files only.
 

3  Return_Values

   x                  The address of a null-terminated string
                      containing a name in UNIX style file
                      specification format.
   0                  Indicates that the filename is null or
                      syntactically incorrect.
   -1                 Indicates that the file specification contains
                      an ellipsis (for example, [ . . . ]a.dat), but
                      is otherwise correct. You cannot translate
                      the OpenVMS ellipsis syntax into a valid UNIX
                      style file specification.
 

3  Example

       /* Demonstrate translation of a "UNIX" name to OpenVMS  */
       /* form, define a foreign command, and pass the name as */
       /* the argument.                                        */

       #include <unixlib.h>
       #include <stdio.h>

       int main(int argc, char *argv[])
       {
           char *ptr;                      /* translation result */

           ptr = decc$translate_vms( argv[1] );

           if ((int) ptr == 0 || (int) ptr == -1)

               printf( "could not translate %s\n", argv[1]);
           else
               printf( "%s is translated to %s\n", argv[1], ptr );
       }
 

2  decc$validate_wchar
   Confirms that its argument is a valid wide character in the
   current program's locale.

   Format

     #include  <unistd.h>

     int decc$validate_wchar  (wchar_t wc);
 

3  Argument
 

wc

   Wide character to be validated.
 

3  Description
   The decc$validate_wchar function provides a convenient way to
   verify whether a specified argument of wchar_t type is a valid
   wide character in the current program's locale.

   One reason to call decc$validate_wchar is that the isw* wide-
   character classification functions and macros do not validate
   their argument before dereferencing the classmask array
   describing character properties. Passing an isw* function a value
   that exceeds the maximum wide-character value for the current
   program's locale can result in an attempt to access memory beyond
   the allocated classmask array.

   A standard way to validate a wide character is to call the wctomb
   function, but this way is less convenient because it requires
   declaring a multibyte character array of sufficient size and
   passing it to wctomb.
 

3  Return_Values

   1                  Indicates that the specified wide character
                      is a valid wide character in the current
                      program's locale.
   0                  Indicates that the specified wide character
                      is not a valid wide character in the current
                      program's locale. errno is not set.
 

2  decc$write_eof_to_mbx
   Writes an end-of-file message to the mailbox.

   Format

     #include  <unistd.h>

     int decc$write_eof_to_mbx  (int fd);
 

3  Argument
 

fd

   File descriptor associated with the mailbox.
 

3  Description
   The decc$write_eof_to_mbx function writes end-of-file message to
   the mailbox.

   For a mailbox that is not a pipe, the write function called with
   an nbytes argument value of 0 sends an end-of-file message to the
   mailbox. For a pipe, however, the only way to write an end-of-
   file message to the mailbox is to close the pipe.

   If the child's standard input is redirected to a pipe through a
   call to the decc$set_child_standard_streams function, the parent
   process can call decc$write_eof_to_mbx for this pipe to send an
   EOF message to the child. It has the same effect as if the child
   read the data from a terminal, and Ctrl/Z was pressed.

   After a call to decc$write_eof_to_mbx, the pipe can be reused
   for communication with another child, for example. This is
   the purpose of decc$write_eof_to_mbx: to allow reuse of the
   pipe instead of having to close it just to send an end-of-file
   message.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates failure; errno and vaxc$errno are
                      set according to the failure status returned
                      by SYS$QIOW.
 

3  Example

       /*      decc$write_eof_to_mbx_example.c         */

       #include <errno.h>
       #include <stdio.h>
       #include <string.h>

       #include <fcntl.h>
       #include <unistd.h>
       #include <unixio.h>

       #include <descrip.h>
       #include <ssdef.h>
       #include <starlet.h>

       int decc$write_eof_to_mbx( int );

       main()
       {
         int status, nbytes, failed = 0;
         int fd, fd2[2];
         short int channel;
         $DESCRIPTOR(mbxname_dsc, "TEST_MBX");
         char c;

         /* first try a mailbox created by SYS$CREMBX        */

       status = sys$crembx(0, &channel, 0, 0, 0, 0, &mbxname_dsc, 0, 0);
       if ( status != SS$_NORMAL ) {
            printf("sys$crembx failed: %s\n",strerror(EVMSERR, status));
            failed = 1;
         }

        if ( (fd = open(mbxname_dsc.dsc$a_pointer, O_RDWR, 0)) == -1) {
             perror("? open mailbox");
             failed = 1;
         }

         if ( decc$write_eof_to_mbx(fd) == -1 ) {
             perror("?  decc$write_eof_to_mbx to mailbox");
             failed = 1;
         }

         if ( (nbytes = read(fd, &c, 1)) != 0 || errno != 0 ) {
             perror("? read mailbox");
             printf("? nbytes = %d\n", nbytes);
             failed = 1;
         }

         if ( close(fd) == -1 ) {
             perror("? close mailbox");
             failed = 1;
         }

         /* Now do the same thing with a pipe                */

         errno = 0;           /* Clear errno for consistency */

         if ( pipe(fd2) == -1 ) {
             perror("? opening pipe");
             failed = 1;
         }

         if ( decc$write_eof_to_mbx(fd2[1]) == -1 ) {
             perror("? decc$write_eof_to_mbx to pipe");
             failed = 1;
         }

         if ( (nbytes = read(fd2[0], &c, 1)) != 0 || errno != 0 ) {
             perror("? read pipe");
             printf("? nbytes = %d\n", nbytes);
             failed = 1;
         }

         /* Close both file descriptors involved with the pipe    */

         if ( close(fd2[0]) == -1 ) {
             perror("close(fd2[0])");
             failed = 1;
         }

         if ( close(fd2[1]) == -1 ) {
             perror("close(fd2[1])");
             failed = 1;
         }

         if ( failed )
             puts("?Example program failed");
         else
             puts("Example ran to completion");
       }

     This example program produces the following result:

       Example ran to completion
 

2  [w]delch
   Delete the character on the specified window at the current
   position of the cursor. The delch function operates on the stdscr
   window.

   Format

     #include  <curses.h>

     int delch();

     int wdelch  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Description
   All of the characters to the right of the cursor on the same line
   are shifted to the left, and a blank character is appended to the
   end of the line.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  delete
   Deletes a file.

   Format

     #include  <unixio.h>

     int delete  (const char *file_spec);
 

3  Argument
 

file_spec

   A pointer to the string that is an OpenVMS or UNIX style file
   specification. The file specification can include a wildcard in
   its version number (but not in any other part of the file spec).
   So, for example, files of the form filename.txt;* can be deleted.
 

3  Description
   If you specify a directory in the filename and it is a search
   list that contains an error, Compaq C for OpenVMS Systems
   interprets it as a file error.

   When delete is used to delete a symbolic link, the link itself is
   deleted, not the file to which it refers.

   The remove and delete functions are functionally equivalent in
   the Compaq C RTL.

   See also remove.

                                  NOTE

      The delete routine is not available to C++ programmers
      because it conflicts with the C++ reserved word delete.
      C++ programmers should use the ANSI/ISO C standard function
      remove instead.
 

3  Return_Values

   0                  Indicates success.
   nonzero value      Indicates that the operation has failed.
 

2  [w]deleteln
   Delete the line at the current position of the cursor. The
   deleteln function acts on the stdscr window.

   Format

     #include  <curses.h>

     int deleteln();

     int wdeleteln  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Description
   Every line below the deleted line moves up, and the bottom line
   becomes blank. The current (y,x) coordinates of the cursor remain
   unchanged.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  delwin
   Deletes the specified window from memory.

   Format

     #include  <curses.h>

     int delwin  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Description
   If the window being deleted contains a subwindow, the subwindow
   is invalidated. Delete subwindows before deleting their parent.
   The delwin function refreshes all windows covered by the deleted
   window.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  difftime
   Computes the difference, in seconds, between the two times
   specified by the time1 and time2 arguments.

   Format

     #include  <time.h>

     double difftime  (time_t time2, time_t time1);
 

3  Arguments
 

time2

   A time value of type time_t.
 

time1

   A time value of type time_t.
 

3  Description
   The type time_t is defined in the <time.h> header file as
   follows:

   typedef unsigned long int time_t
 

3  Return_Value

   n                  time2 - time1 in seconds expressed as a
                      double.
 

2  dirname
   Reports the parent directory name of a file pathname.

   Format

     #include  <libgen.h>

     char *dirname  (char *path);
 

3  Function_Variants
   The dirname function has variants named _dirname32 and _dirname64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Argument
 

path

   The file pathname.
 

3  Description
   The dirname function takes a pointer to a character string that
   contains a UNIX pathname and returns a pointer to a string that
   is a pathname of the parent directory of that file. Trailing
   slash (/)  characters in the path are not counted as part of the
   path.

   This function returns a pointer to the string "." (dot), when the
   path argument:

   o  Does not contain a slash (/).

   o  Is a NULL pointer.

   o  Points to an empty string.

   The dirname function can modify the string pointed to by the path
   argument.

   The dirname and basename functions together yield a complete
   pathname. The expression dirname(path) obtains the pathname of
   the directory where basename(path) is found.

   See also basename.
 

3  Return_Values

   x                  A pointer to a string that is the parent
                      directory of the path argument.
   "."                The path argument:

                      o  Does not contain a slash (/).

                      o  Is a NULL pointer.

                      o  Points to an empty string.
 

3  Example

     Using the dirname function, the following example reads a
     pathname, changes the current working directory to the parent
     directory, and opens a file.

           char path [MAXPATHLEN], *pathcopy;
           int fd;

           fgets(path, MAXPATHLEN, stdin);
           pathcopy = strdup(path);
           chdir(dirname(pathcopy));
           fd = open(basename(path), O_RDONLY);
 

2  div
   Returns the quotient and the remainder after the division of its
   arguments.

   Format

     #include  <stdlib.h>

     div_t div  (int numer, int denom);
 

3  Arguments
 

numer

   A numerator of type int.
 

denom

   A denominator of type int.
 

3  Description
   The type div_t is defined in the standard header file <stdlib.h>
   as follows:

   typedef struct
           {
                int   quot, rem;
           } div_t;
 

2  dlclose
   Deallocates the address space for a shared library.

   Format

     #include  <dlfcn.h>

     void dlclose  (void *handle);
 

3  Argument
 

handle

   Pointer to the shared library.
 

3  Description
   The dlclose function deallocates the address space allocated by
   the Compaq C RTL for the handle.

   There is no way on OpenVMS systems to unload a shareable image
   dynamically loaded by the LIB$FIND_IMAGE_SYMBOL routine, which
   is the routine called by the dlsym function. In other words,
   there is no way on OpenVMS systems to release the address space
   occupied by the shareable image brought into memory by dlsym.
 

2  dlerror
   Returns a string describing the last error that occurred from a
   call to dlopen, dlclose, or dlsym.

   Format

     #include  <dlfcn.h>

     char *dlerror  (void);
 

3  Return_Value

   x                  A string describing the last error that
                      occurred from a call to dlopen, dlclose, or
                      dlsym.
 

2  dlopen
   Provides an interface to the dynamic library loader to allow
   shareable images to be loaded and called at run time.

   Format

     #include  <dlfcn.h>

     void *dlopen  (char *pathname, int mode);
 

3  Arguments
 

pathname

   The name of the shareable image. This name is saved for
   subsequent use by the dlsym function.
 

mode

   This argument is ignored on OpenVMS systems.
 

3  Description
   The dlopen function provides an interface to the dynamic library
   loader to allow shareable images to be loaded and called at run
   time.

   This function does not load a shareable image but rather saves
   its pathname argument for subsequent use by the dlsym function.
   dlsym is the function that actually loads the shareable image
   through a call to LIB$FIND_IMAGE_SYMBOL.

   The pathname argument of the dlopen function must be the name
   of the shareable image. This name is passed as-is by the dlsym
   function to the LIB$FIND_IMAGE_SYMBOL routine as the filename
   argument. No image-name argument is specified in the call
   to LIB$FIND_IMAGE_SYMBOL, so default file specification of
   SYS$SHARE:.EXE is applied to the image name.

   The dlopen function returns a handle that is used by a dlsym or
   dlclose call. If an error occurs, a NULL pointer is returned.
 

3  Return_Values

   x                  A handle to be used by a dlsym or dlclose
                      call.
   NULL               Indicates an error.
 

2  dlsym
   Returns the address of the symbol name found in a shareable
   image.

   Format

     #include  <dlfcn.h>

     void *dlsym  (void *handle, char *name);
 

3  Arguments
 

handle

   Pointer to the shareable image.
 

name

   Pointer to the symbol name.
 

3  Description
   The dlsym function returns the address of the symbol name found
   in the shareable image corresponding to handle. If the symbol is
   not found, a NULL pointer is returned.

   As of OpenVMS Version 7.3-2, library symbols containing
   lowercase characters can be loaded using the dlsym function. More
   generally, the functions that dynamically load libraries (dlopen,
   dlsym, dlclose, dlerror) are enhanced to provide the following
   capabilities:

   o  Support for libraries with mixed-case symbol names

   o  Ability to pass a full file path to dlopen

   o  Validation of the specified library name
 

3  Return_Values

   x                  Address of the symbol name found.
   NULL               Indicates that the symbol was not found.
 

2  drand48
   Generates uniformly distributed pseudorandom-number sequences.
   Returns 48-bit, nonnegative, double-precision floating-point
   values.

   Format

     #include  <stdlib.h>

     double drand48  (void);
 

3  Description
   The drand48 function generates pseudorandom numbers using the
   linear congruential algorithm and 48-bit integer arithmetic.

   It returns nonnegative, double-precision, floating-point values
   uniformly distributed over the range of y values such that 0.0    y < 1.0.

   Before you call drand48, use either srand48, seed48, or lcong48
   to initialize the random-number generator. You must initialize
   prior to invoking the drand48 function because it stores the last
   48-bit Xi generated into an internal buffer. (Although it is not
   recommended, constant default initializer values are supplied
   automatically if the drand48, lrand48, or mrand48 functions are
   called without first calling an initialization function.)

   The drand48 function works by generating a sequence of 48-bit
   integer values, Xi, according to the linear congruential formula:

          Xn+1 = (aXn+c)mod m        n >= 0

   The argument m equals 248, so 48-bit integer arithmetic is

   performed. Unless you invoke lcong48, the multiplier value a
   and the addend value c are:

        a = 5DEECE66D16 = 2736731631558

        c = B16 = 138

   The values returned by drand48 are computed by first generating
   the next 48-bit Xi in the sequence. Then the appropriate bits,
   according to the type of returned data item, are copied from the
   high-order (most significant) bits of Xi and transformed into the
   returned value.

   See also srand48, seed48, lcong48, lrand48, and mrand48.
 

3  Return_Value

   n                  A nonnegative, double-precision, floating-
                      point value.
 

2  dup,dup2
   Allocate a new descriptor that refers to a file specified by a
   file descriptor returned by open, creat, or pipe.

   Format

     #include  <unistd.h>

     int dup  (int file_desc1);

     int dup2  (int file_desc1, int file_desc2);
 

3  Arguments
 

file_desc1

   The file descriptor being duplicated.
 

file_desc2

   The new file descriptor to be assigned to the file designated by
   file_desc1.
 

3  Description
   The dup function causes a previously unallocated descriptor to
   refer to its argument, while the dup2 function causes its second
   argument to refer to the same file as its first argument.

   The argument file_desc1 is invalid if it does not describe an
   open file; file_desc2 is invalid if the new file descriptor
   cannot be allocated. If file_desc2 is connected to an open file,
   that file is closed.
 

3  Return_Values

   n                  The new file descriptor.
   -1                 Indicates that an invalid argument was passed
                      to the function.
 

2  [no]echo
   Set the terminal so that characters may or may not be echoed on
   the terminal screen. This mode of single-character input is only
   supported with Curses.

   Format

     #include  <curses.h>

     void echo  (void);

     void noecho  (void);
 

3  Description
   The noecho function may be helpful when accepting input from the
   terminal screen with wgetch and wgetstr; it prevents the input
   characters from being written onto the screen.
 

2  ecvt
   Converts its argument to a null-terminated string of ASCII digits
   and returns the address of the string. The string is stored in a
   thread-specific memory location created by the Compaq C RTL.

   Format

     #include  <stdlib.h>

     char *ecvt  (double value, int ndigits, int *decpt, int *sign);
 

3  Arguments
 

value

   An object of type double that is converted to a null-terminated
   string of ASCII digits.
 

ndigits

   The number of ASCII digits to be used in the converted string.
 

decpt

   The position of the decimal point relative to the first character
   in the returned string. A negative int value means that the
   decimal point is decpt number of spaces to the left of the
   returned digits (the spaces being filled with zeros). A 0 value
   means that the decimal point is immediately to the left of the
   first digit in the returned string.
 

sign

   An integer value that indicates whether the value argument is
   positive or negative. If value is negative, the function places
   a nonzero value at the address specified by sign. Otherwise, the
   function assigns 0 to the address specified by sign.
 

3  Description
   The ecvt function converts value to a null-terminated string
   of length ndigits, and returns a pointer to it. The resulting
   low-order digit is rounded to the correct digit for outputting
   ndigits digits in C E-format. The decpt argument is assigned the
   position of the decimal point relative to the first character in
   the string.

   Repeated calls to the ecvt function overwrite any existing
   string.

   The ecvt, fcvt, and gcvt functions represent the following
   special values specified in the IEEE Standard for floating-point
   arithmetic:
 

   Value         Representation

   Quiet NaN     NaNQ
   Signalling    NaNS
   NaN
   +Infinity     Infinity
   -Infinity     -Infinity

   The sign associated with each of these values is stored into the
   sign argument. In IEEE floating-point representation, a value
   of 0 (zero) can be positive or negative, as set by the sign
   argument.

   See also gcvt and fcvt.
 

3  Return_Value

   x                  The value of the converted string.
 

2  encrypt
   Encrypts a string using the key generated by the setkey function.

   Format

     #include  <unistd.h>

     #include  <stdlib.h>

     void encrypt  (char *block[64], int edflag;)
 

3  Argument
 

block

   A character array of length 64 containing 0s and 1s.
 

edflag

   An integer. If edflag is 0, the argument is encrypted; if
   nonzero, it is decrypted.
 

3  Description
   The encrypt function encrypts a string using the key generated by
   the setkey function.

   The first argument to encrypt is a character array of length 64
   containing 0s and 1s. The argument array is modified in place
   to a similar array representing the bits of the argument after
   having been subjected to the DES algorithm using the key set by
   setkey.

   The second argument, edflag, determines whether the first
   argument is encrypted or decrypted: if edflag is 0, the first
   argument array is encrypted; if nonzero, it is decrypted.

   No value is returned.

   See also crypt and setkey.
 

3  Return_Value

   pointer            Pointer to the encrypted password.
 

2  endgrent
   Closes the group database when processing is complete.

   Format

     #include  <grp.h>

     void endgrent  (void);
 

3  Description
   The endgrent function closes the group database.

   This function is always successful. No value is returned, and
   errno is not set.
 

2  endpwent
   Closes the user database and any private stream used by getpwent.

   Format

     #include  <pwd.h>

     void endpwent  (void);
 

3  Description
   The endpwent function closes the user database and any private
   stream used by getpwent.

   No value is returned. If an I/O error occurred, the function sets
   errno to EIO.

   See also getpwent, getpwuid, getpwnam, and setpwent.
 

2  endwin
   Clears the terminal screen and frees any virtual memory allocated
   to Curses data structures.

   Format

     #include  <curses.h>

     void endwin  (void);
 

3  Description
   A program that calls Curses functions must call the endwin
   function before exiting to restore the previous environment of
   the terminal screen.
 

2  erand48
   Generates uniformly distributed pseudorandom-number sequences.
   Returns 48-bit nonnegative, double-precision, floating-point
   values.

   Format

     #include  <stdlib.h>

     double erand48  (unsigned short int xsubi[3]);
 

3  Argument
 

xsubi

   An array of three short ints, which form a 48-bit integer when
   concatenated together.
 

3  Description
   The erand48 function generates pseudorandom numbers using the
   linear congruential algorithm and 48-bit integer arithmetic.

   It returns nonnegative, double-precision, floating-point values
   uniformly distributed over the range of y values, such that 0.0
   <= y < 1.0.

   The erand48 function works by generating a sequence of 48-bit
   integer values, Xi, according to the linear congruential formula:

          Xn+1 = (aXn+c)mod m        n >= 0

   The argument m equals 248, so 48-bit integer arithmetic is

   performed. Unless you invoke the lcong48 function, the multiplier
   value a and the addend value c are:

         a = 5DEECE66D16 = 2736731631558

         c = B16 = 138

   The erand48 function requires that the calling program pass an
   array as the xsubi argument. For the first call, the array must
   be initialized to the value of the pseudorandom-number sequence.
   Unlike the drand48 function, it is not necessary to call an
   initialization function prior to the first call.

   By using different arguments, the erand48 function allows
   separate modules of a large program to generate several
   independent sequences of pseudorandom numbers; for example, the
   sequence of numbers that one module generates does not depend
   upon how many times the function is called by other modules.
 

3  Return_Value

   n                  A nonnegative, double-precision, floating-
                      point value.
 

2  [w]erase
   Erases the window by painting it with blanks. The erase function
   acts on the stdscr window.

   Format

     #include  <curses.h>

     int erase();

     int werase  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Description
   Both the erase and werase functions leave the cursor at the
   current position on the terminal screen after completion; they
   do not return the cursor to the home coordinates of (0,0).
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  erf
   Returns the error function of its argument.

   Format

     #include  <math.h>

     double erf  (double x);

     float erff  (float x); (Integrity servers, Alpha)

     long double erfl  (long double x); (Integrity servers, Alpha)

     double erfc  (double x); (Integrity servers, Alpha)

     float erfcf  (float x); (Integrity servers, Alpha)

     long double erfcl  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A radian expressed as a real number.
 

3  Description
   The erf functions return the error function of x, where erf(x),
   erff(x), and erfl(x) equal 2/sqrt(pi) times the area under the
   curve e**(-t**2) between 0 and x.

   The erfc functions return (1.0 - erf(x)). The erfc function can
   result in an underflow as x gets large.
 

3  Return_Values

   x                  The value of the error function (erf) or
                      complementary error function (erfc).
   NaN                x is NaN; errno is set to EDOM.
   0                  Underflow occurred; errno is set to ERANGE.
 

2  execl
   Passes the name of an image to be activated in a child process.
   This function is nonreentrant.

   Format

     #include  <unistd.h>

     int execl  (const char *file_spec, const char *arg0, . . . ,  
                (char *)0); (ISO POSIX-1)

     int execl  (char *file_spec, . . . ); (Compatibility)
 

3  Arguments
 

file_spec

   The full file specification of a new image to be activated in the
   child process.
 

arg0, ...

   A sequence of pointers to null-terminated character strings.

   If the POSIX-1 format is used, at least one argument must be
   present and must point to a string that is the same as the new
   process filename (or its last component). (This pointer can also
   be the NULL pointer, but then execle would accomplish nothing.)
   The last pointer must be the NULL pointer. This is also the
   convention if the compatibility format is used.
 

3  Description
   To understand how the exec functions operate, consider how
   the OpenVMS system calls any Compaq C program, as shown in the
   following syntax:

   int main (int argc, char *argv[], char *envp[]);

   The identifier argc is the argument count; argv is an array
   of argument strings. The first member of the array (argv[0])
   contains the name of the image. The arguments are placed in
   subsequent elements of the array. The last element of the array
   is always the NULL pointer.

   An exec function calls a child process in the same way that
   the run-time system calls any other Compaq C program. The exec
   functions pass the name of the image to be activated in the
   child; this value is placed in argv[0]. However, the functions
   differ in the way they pass arguments and environment information
   to the child:

   o  Arguments can be passed in separate character strings (execl,
      execle, and execlp) or in an array of character strings
      (execv, execve, and execvp).

   o  The environment can be explicitly passed in an array (execle
      and execve) or taken from the parent's environment (execl,
      execv, execlp, and execvp).

   If vfork was called before invoking an exec function, then when
   the exec function completes, control is returned to the parent
   process at the point of the vfork call. If vfork was not called,
   the exec function waits until the child has completed execution
   and then exits the parent process. See vfork.
 

3  Return_Value

   -1                 Indicates failure.
 

2  execle
   Passes the name of an image to be activated in a child process.
   This function is nonreentrant.

   Format

     #include  <unistd.h>

     int execle  (char *file_spec, char *arg0, . . . , (char *)0, 
                 char *envp[]); (ISO POSIX-1)

     int execle  (char *file_spec, . . . ); (Compatibility)
 

3  Arguments
 

file_spec

   The full file specification of a new image to be activated in the
   child process.
 

arg0, ...

   A sequence of pointers to null-terminated character strings.

   If the POSIX-1 format is used, at least one argument must be
   present and must point to a string that is the same as the new
   process filename (or its last component). (This pointer can also
   be the NULL pointer, but then execle would accomplish nothing.)
   The last pointer must be the NULL pointer. This is also the
   convention if the compatibility format is used.
 

envp

   An array of strings that specifies the program's environment.
   Each string in envp has the following form:

   name = value

   The name can be one of the following names and the value is a
   null-terminated string to be associated with the name:

   o  HOME-Your login directory

   o  TERM-The type of terminal being used

   o  PATH-The default device and directory

   o  USER-The name of the user who initiated the process

   The last element in envp must be the NULL pointer.

   When the operating system executes the program, it places a copy
   of the current environment vector (envp) in the external variable
   environ.
 

3  Description
   See execl for a description of how the exec functions operate.
 

3  Return_Value

   -1                 Indicates failure.
 

2  execlp
   Passes the name of an image to be activated in a child process.
   This function is nonreentrant.

   Format

     #include  <unistd.h>

     int execlp  (const char *file_name, const char *arg0, . . . ,  
                 (char *)0); (ISO POSIX-1)

     int execlp  (char *file_name, . . . ); (Compatibility)
 

3  Arguments
 

file_name

   The filename of a new image to be activated in the child process.
   The device and directory specification for the file is obtained
   by searching the VAXC$PATH environment name.
 

argn

   A sequence of pointers to null-terminated character strings. By
   convention, at least one argument must be present and must point
   to a string that is the same as the new process filename (or its
   last component).
 

 . . .

   A sequence of pointers to strings. At least one pointer must
   exist to terminate the list. This pointer must be the NULL
   pointer.
 

3  Description
   See execl for a description of how the exec functions operate.
 

3  Return_Value

   -1                 Indicates failure.
 

2  execv
   Passes the name of an image to be activated in a child process.
   This function is nonreentrant.

   Format

     #include  <unistd.h>

     int execv  (char *file_spec, char *argv[]);
 

3  Arguments
 

file_spec

   The full file specification of a new image to be activated in the
   child process.
 

argv

   An array of pointers to null-terminated character strings.
   These strings constitute the argument list available to the new
   process. By convention, argv[0] must point to a string that is
   the same as the new process filename (or its last component).
   argv is terminated by a NULL pointer.
 

3  Description
   See execl for a description of how the exec functions operate.
 

3  Return_Value

   -1                 Indicates failure.
 

2  execve
   Passes the name of an image to be activated in a child process.
   This function is nonreentrant.

   Format

     #include  <unistd.h>

     int execve  (const char *file_spec, char *argv[], char *envp[]);
 

3  Arguments
 

file_spec

   The full file specification of a new image to be activated in the
   child process.
 

argv

   An array of pointers to null-terminated character strings.
   These strings constitute the argument list available to the new
   process. By convention, argv[0] must point to a string that is
   the same as the new process filename (or its last component).
   argv is terminated by a NULL pointer.
 

envp

   An array of strings that specifies the program's environment.
   Each string in envp has the following form:

   name = value

   The name can be one of the following names and the value is a
   null-terminated string to be associated with the name:

   o  HOME-Your login directory

   o  TERM-The type of terminal being used

   o  PATH-The default device and directory

   o  USER-The name of the user who initiated the process

   The last element in envp must be the NULL pointer.

   When the operating system executes the program, it places a copy
   of the current environment vector (envp) in the external variable
   environ.
 

3  Description
   See execl for a description of how the exec functions operate.
 

3  Return_Value

   -1                 Indicates failure.
 

2  execvp
   Passes the name of an image to be activated in a child process.
   This function is nonreentrant.

   Format

     #include  <unistd.h>

     int execvp  (const char *file_name, char *argv[]);
 

3  Arguments
 

file_name

   The filename of a new image to be activated in the child process.
   The device and directory specification for the file is obtained
   by searching the environment name VAXC$PATH.
 

argv

   An array of pointers to null-terminated character strings.
   These strings constitute the argument list available to the new
   process. By convention, argv[0] must point to a string that is
   the same as the new process filename (or its last component).
   argv is terminated by a NULL pointer.
 

3  Description
   See execl for a description of how the exec functions operate.
 

3  Return_Value

   -1                 Indicates failure.
 

2  exit,_exit
   Terminate execution of the program from which they are called.
   These functions are nonreentrant.

   Format

     #include  <stdlib.h>

     void exit  (int status);

     #include  <unistd.h>

     void _exit  (int status);
 

3  Argument
 

status

   For non-POSIX behavior, a status value of EXIT_SUCCESS (1), EXIT_
   FAILURE (2), or a number from 3 to 255, as follows:

   o  A status value of 0, 1 or EXIT_SUCCESS is translated to the
      OpenVMS SS$_NORMAL status code to return the OpenVMS success
      value.

   o  A status value of 2 or EXIT_FAILURE is translated to an error-
      level exit status. The status value is passed to the parent
      process.

   o  Any other status value is left the same.

   For POSIX behavior:

   o  A status value of 0 is translated to the OpenVMS SS$_NORMAL
      status code to return the OpenVMS success value.

   o  Any other status is returned to the parent process as an
      OpenVMS message symbol with facility set to C, severity
      set to success, and with the status in the message number
      field. For more information on the format of message symbols,
      see "message code" in the HP OpenVMS Command Definition,
      Librarian, and Message Utilities Manual.

   To get POSIX behavior, include <unistd.h> and compile with the
   _POSIX_EXIT feature-test macro set (either with /DEFINE=_POSIX_
   EXIT, or with #define _POSIX_EXIT at the top of your file, before
   any file inclusions). This behavior is available only on OpenVMS
   Version 7.0 and higher systems.
 

3  Description
   If the process was invoked by DCL, the status is interpreted by
   DCL, and a message is displayed.

   If the process was a child process created using vfork or an exec
   function, then the child process exits and control returns to the
   parent. The two functions are identical; the _exit function is
   retained for reasons of compatibility with VAX C.

   The exit and _exit functions make use of the $EXIT system
   service. If your process is being invoked by the RUN command
   using any of the hibernation and scheduled wakeup qualifiers, the
   process might not correctly return to hibernation state when an
   exit or _exit call is made.

   The C compiler command-line qualifier /[NO]MAIN=POSIX_EXIT can be
   used to direct the compiler to call __posix_exit instead of exit
   when returning from main. The default is /NOMAIN.

   Beginning with OpenVMS Version 8.3, C RTL contains a fix for
   the problem in which a call to _exit after a failed execl really
   exits but must not.

   In the OpenVMS implementation of vfork, a child process is not
   actually started as it is started on most UNIX systems. However,
   the C RTL creates some internal data structures intended to mimic
   child-process functionality (called the "child context").

   A bug occurred whereby after a vfork while in the child context,
   a call to an exec function justifiably fails, then calls _exit.
   On UNIX systems, after the failed exec call, the child process
   continues to execute. A subsequent call to _exit terminates
   the child. In the OpenVMS implementation, after the failed exec
   call, the child context terminates. A subsequent call to _exit
   terminates the parent. The C RTL fix is enabled by a feature
   logical switch, DECC$EXIT_AFTER_ FAILED_EXEC. Enabling this
   feature logical allows the child context to continue execution.

   With DECC$EXIT_AFTER_FAILED_EXEC disabled or not defined, the
   current behavior remains the default.

                                  NOTE

      EXIT_SUCCESS and EXIT_FAILURE are portable across any
      ANSI C compiler to indicate success or failure. On OpenVMS
      systems, they are mapped to OpenVMS condition codes with
      the severity set to success or failure, respectively. Values
      in the range of 3 to 255 can be used by a child process to
      communicate a small amount of data to the parent. The parent
      retrieves this data using the wait, wait3, wait4, or waitpid
      functions.
 

2  exp
   Returns the base e raised to the power of the argument.

   Format

     #include  <math.h>

     double exp  (double x);

     float expf  (float x); (Integrity servers, Alpha)

     long double expl  (long double x); (Integrity servers, Alpha)

     double expm1  (double x); (Integrity servers, Alpha)

     float expm1f  (float x); (Integrity servers, Alpha)

     long double expm1l  (long double x);                   
                         (Integrity servers, Alpha)
 

3  Argument
 

x

   A real value.
 

3  Description
   The exp functions compute the value of the exponential function,
   defined as e**x, where e is the constant used as a base for
   natural logarithms.

   The expm1 functions compute exp(x) - 1 accurately, even for tiny
   x.

   If an overflow occurs, the exp functions return the largest
   possible floating-point value and set errno to ERANGE. The
   constant HUGE_VAL is defined in the <math.h> header file to be
   the largest possible floating-point value.
 

3  Return_Values

   x                  The exponential value of the argument.
   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
   0                  Underflow occurred; errno is set to ERANGE.
   NaN                x is NaN; errno is set to EDOM.
 

2  exp2
   Returns the value of 2 raised to the power of the argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double exp2  (double x);

     float exp2f  (float x);

     long double exp2l  (long double x); )
 

3  Argument
 

x

   A real value.
 

3  Description
   The exp2 functions compute the base-2 exponential of x.

   If an overflow occurs, the exp functions return the largest
   possible floating-point value and set errno to ERANGE. The
   constant HUGE_VAL is defined in the <math.h> header file to be
   the largest possible floating-point value.
 

3  Return_Values

   n                  2**x.
   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
   1                  x is +0 or -0; errno is set to ERANGE.
   0                  x is -Inf or underflow occurred; errno is set
                      to ERANGE.
   x                  x is +Inf; errno is set to ERANGE.
   NaN                x is NaN; errno is set to EDOM.
 

2  fabs
   Returns the absolute value of its argument.

   Format

     #include  <math.h>

     double fabs  (double x);

     float fabsf  (float x); (Integrity servers, Alpha)

     long double fabsl  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A real value.
 

3  Return_Value

   x                  The absolute value of the argument.
 

2  fchmod
   Changes file access permissions.

   Format

     #include  <stat.h>

     int fchmod  (int fildes, mode_t mode);
 

3  Arguments
 

fildes

   An open file descriptor.
 

mode

   The bit pattern that determines the access permissions.
 

3  Description
   The fchmod function is equivalent to the chmod function, except
   that the file whose permissions are changed is specified by a
   file descriptor (fildes) rather than a filename.
 

3  Return_Values

   0                  Indicates that the mode is successfully
                      changed.
   -1                 Indicates that the change attempt has failed.
 

2  fchown
   Changes the owner and group of a file.

   Format

     #include  <unistd.h>

     int fchown  (int fildes, uid_t owner, gid_t group);
 

3  Arguments
 

fildes

   An open file descriptor.
 

owner

   A user ID corresponding to the new owner of the file.
 

group

   A group ID corresponding to the group of the file.
 

3  Description
   The fchown function has the same effect as chown except that the
   file whose owner and group are to be changed is specified by the
   file descriptor fildes.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates failure. The function sets errno to
                      one of the following values:

                      The fchown function will fail if:

                      o  EBADF - The fildes argument is not an open
                         file descriptor.

                      o  EPERM - The effective user ID does not
                         match the owner of the file, or the process
                         does not have appropriate privilege.

                      o  EROFS - The file referred to by fildes
                         resides on a read-only file system.

                      The fchown function may fail if:

                      o  EINVAL - The owner or group ID is not a
                         value supported by the implementation.

                      o  EIO - A physical I/O error has occurred.

                      o  EINTR - The fchown function was interrupted
                         by a signal that was intercepted.
 

2  fclose
   Closes a file by flushing any buffers associated with the file
   control block and freeing the file control block and buffers
   previously associated with the file pointer.

   Format

     #include  <stdio.h>

     int fclose  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A pointer to the file to be closed.
 

3  Description
   When a program terminates normally, the fclose function is
   automatically called for all open files.

   The fclose function tries to write buffered data by using an
   implicit call to fflush.

   If the write fails (because the disk is full or the user's quota
   is exceeded, for example), fclose continues executing. It closes
   the OpenVMS channel, deallocates any buffers, and releases the
   memory associated with the file descriptor (or FILE pointer). Any
   buffered data is lost, and the file descriptor (or FILE pointer)
   no longer refers to the file.

   If your program needs to recover from errors when flushing
   buffered data, it should make an explicit call to fsync (or
   fflush) before calling fclose.
 

3  Return_Values

   0                  Indicates success.
   EOF                Indicates that the file control block is not
                      associated with an open file.
 

2  fcntl
   Performs controlling operations on an open file.

   Format

     #include  <sys/types.h>

     #include  <unistd.h>

     #include  <fcntl.h>

     int fcntl  (int file_desc, int request [, int arg]);

     int fcntl  (int file_desc, int request [, struct flock *arg]);
 

3  Arguments
 

file_desc

   An open file descriptor obtained from a successful open, fcntl,
   or pipe function.
 

request

   The operation to be performed.
 

arg

   A variable that depends on the value of the request argument.

   For a request of F_DUPFD, F_SETFD, or F_SETFL, specify arg as an
   int.

   For a request of F_GETFD and F_GETFL, do not specify arg.

   For a request of F_GETLK, F_SETLK, or F_SETLKW specify arg as a
   pointer to a flock structure.
 

3  Description
   The fcntl function performs controlling operations on the open
   file specified by the file_desc argument.

   The values for the request argument are defined in the header
   file <fcntl.h>, and include the following:

   F_DUPFD      Returns a new file descriptor that is the lowest
                numbered available (that is, not already open)
                file descriptor greater than or equal to the third
                argument (arg) taken as an integer of type int.

                The new file descriptor refers to the same file as
                the original file descriptor (file_desc). The FD_
                CLOEXEC flag associated with the new file descriptor
                is cleared to keep the file open across calls to one
                of the exec functions.


                The following two calls are equivalent:

                fid = dup(file_desc);

                fid = fcntl(file_desc, F_DUPFD, 0);

                Consider the following call:

                fid = dup2(file_desc, arg);

                It is similar (but not equivalent) to:

                close(arg);
                fid = fcntl(file_desc, F_DUPFD, arg);
   F_GETFD      Gets the value of the close-on-exec flag associated
                with the file descriptor file_desc. File descriptor
                flags are associated with a single file descriptor
                and do not affect other file descriptors that refer
                to the same file. The arg argument should not be
                specified.
   F_SETFD      Sets the close-on-exec flag associated with file_
                desc to the value of the third argument, taken as
                type int.

                If the third argument is 0, the file remains open
                across the exec functions, which means that a child
                process spawned by the exec function inherits this
                file descriptor from the parent.

                If the third argument is FD_CLOEXEC, the file is
                closed on successful execution of the next exec
                function, which means that the child process spawned
                by the exec function will not inherit this file
                descriptor from the parent.
   F_GETFL      Gets the file status flags and file access modes,
                defined in <fcntl.h>, for the file description
                associated with file_desc. The file access modes
                can be extracted from the return value using the
                mask O_ACCMODE, which is defined in <fcntl.h>. File
                status flags and file access modes are associated
                with the file description and do not affect other
                file descriptors that refer to the same file with
                different open file descriptions.
   F_SETFL      Sets the file status flags, defined in <fcntl.h>,
                for the file description associated with file_desc
                from the corresponding bits in the third argument,
                arg, taken as type int. Bits corresponding to the
                file access mode and the file creation flags,
                as defined in <fcntl.h>, that are set in arg
                are ignored. If any bits in arg other than those
                mentioned here are changed by the application, the
                result is unspecified.

                Note: The only status bit recognized is O_APPEND.
                Support for O_APPEND is not standard-compliant.
                The X/Open standard states that "File status flags
                and file access modes are associated with the file
                description and do not affect other file descriptors
                that refer to the same file with different open
                file descriptions." However, because the append bit
                is stored in the FCB, all file descriptors using
                the same FCB are using the same append flag, so
                that setting this flag with fcntl(F_SETFL) will
                affect all files sharing the FCB; that is, all files
                duplicated from the same file descriptor.

   Record Locking Requests

   F_GETLK      Gets the first lock that blocks the lock description
                pointed to by the arg parameter, taken as a pointer
                to type struct flock. The information retrieved
                overwrites the information passed to the fcntl
                function in the flock structure. If no lock is found
                that would prevent this lock from being created,
                then the structure is left unchanged except for the
                lock type, which is set to F_UNLCK.
   F_SETLK      Sets or clears a file segment lock according to
                the lock description pointed to by arg, taken as
                a pointer to type struct flock. F_SETLK is used to
                establish shared locks (F_RDLCK), or exclusive locks
                (F_WRLCK), as well as remove either type of lock (F_
                UNLCK). If a shared (read) or exclusive (write)
                lock cannot be set, the fcntl function returns
                immediately with a value of -1.


                An unlock (F_UNLCK) request in which the l_len of
                the flock structure is nonzero and the offset of the
                last byte of the requested segment is the maximum
                value for an object of type off_t, when the process
                has an existing lock in which l_len is 0 and which
                includes the last byte of the requested segment,
                is treated as a request to unlock from the start
                of the requested segment with an l_len equal to 0.
                Otherwise, an unlock (F_UNLCK) request attempts to
                unlock only the requested file.
   F_SETLKW     Same as F_SETLK except that if a shared or exclusive
                lock is blocked by other locks, the process will
                wait until it is unblocked. If a signal is received
                while fcntl is waiting for a region, the function
                is interrupted, -1 is returned, and errno is set to
                EINTR.

   File Locking

   The C RTL supports byte-range file locking using the F_GETLK,
   F_SETLK, and F_SETLKW commands of the fcntl function, as defined
   in the X/Open specification. Byte-range file locking is supported
   across OpenVMS clusters. You can only use offsets that fit into
   32-bit unsigned integers.

   When a shared lock is set on a segment of a file, other processes
   on the cluster are able to set shared locks on that segment or
   a portion of it. A shared lock prevents any other process from
   setting an exclusive lock on any portion of the protected area.
   A request for a shared lock fails if the file descriptor was not
   opened with read access.

   An exclusive lock prevents any other process on the cluster from
   setting a shared lock or an exclusive lock on any portion of the
   protected area. A request for an exclusive lock fails if the file
   descriptor was not opened with write access.

   The flock structure describes the type (l_type), starting offset
   (l_whence), relative offset (l_start), size (l_len) and process
   ID (l_pid) of the segment of the file to be affected.

   The value of l_whence is set to SEEK_SET, SEEK_CUR or SEEK_END,
   to indicate that the relative offset l_start bytes is measured
   from the start of the file, from the current position, or from
   the end of the file, respectively. The value of l_len is the
   number of consecutive bytes to be locked. The l_len value may be
   negative (where the definition of off_t permits negative values
   of l_len). The l_pid field is only used with F_GETLK to return
   the process ID of the process holding a blocking lock. After a
   successful F_GETLK request, the value of l_whence becomes SEEK_
   SET.

   If l_len is positive, the area affected starts at l_start and
   ends at l_start + l_len - 1. If l_len is negative, the area
   affected starts at l_start + l_len and ends at l_start - 1. Locks
   may start and extend beyond the current end of a file, but may
   not be negative relative to the beginning of the file. If l_len
   is set to 0 (zero), a lock may be set to always extend to the
   largest possible value of the file offset for that file. If such
   a lock also has l_start set to 0 (zero) and l_whence is set to
   SEEK_SET, the whole file is locked.

   Changing or unlocking a portion from the middle of a larger
   locked segment leaves a smaller segment at either end. Locking
   a segment that is already locked by the calling process causes
   the old lock type to be removed and the new lock type to take
   effect.

   All locks associated with a file for a given process are removed
   when a file descriptor for that file is closed by that process
   or the process holding that file descriptor terminates. Locks are
   not inherited by a child process.

   If the request argument is F_SETLKW, the lock is blocked by
   some lock from another process, and putting the calling process
   to sleep to wait for that lock to become free would cause a
   deadlock, then the application will hang.
 

3  Return_Values

   n                  Upon successful completion, the value returned
                      depends on the value of the request argument
                      as follows:

                      o  F_DUPFD - Returns a new file descriptor.

                      o  F_GETFD - Returns FD_CLOEXEC or 0.

                      o  F_SETFD, F_GETLK, F_SETLK, F_UNLCK - Return
                         a value other than -1.

   -1                 Indicates that an error occurred. The function
                      sets errno to one of the following values:

                      o  EACCES - The request argument is F_SETLK;
                         the type of lock (l_type) is a shared (F_
                         RDLCK) or exclusive (F_WRLCK) lock, and the
                         segment of a file to be locked is already
                         exclusive-locked by another process; or
                         the type is an exclusive (F_WRLCK) lock and
                         the some portion of the segment of a file
                         to be locked is already shared-locked or
                         exclusive-locked by another process.

                      o  EBADF - The file_desc argument is not a
                         valid open file descriptor and the arg
                         argument is negative or greater than or
                         equal to the per-process limit.

                         The request parameter is F_SETLK or F_
                         SETLKW, the type of lock (l_type) is a
                         shared lock (F_RDLCK), and file_desc is not
                         a valid file descriptor open for reading.

                         The type of lock (l_type) is an exclusive
                         lock (F_WRLCK), and file_desc is not a
                         valid file descriptor open for writing.

                      o  EFAULT - The arg argument is an invalid
                         address.

                      o  EINVAL - The request argument is F_DUPFD
                         and arg is negative or greater than or
                         equal to OPEN_MAX.

                         Either the OPEN_MAX value or the per-
                         process soft descriptor limit is checked.

                         An illegal value was provided for the
                         request argument.

                         The request argument is F_GETLK, F_SETLK,
                         or F_SETLKW and the data pointed to by arg
                         is invalid, or file_desc refers to a file
                         that does not support locking.

                      o  EMFILE - The request argument is F_DUPFD
                         and too many or OPEN_MAX file descriptors
                         are currently open in the calling process,
                         or no file descriptors greater than or
                         equal to arg are available.

                         Either the OPEN_MAX value or the per-
                         process soft descriptor limit is checked.


                      o  EOVERFLOW - One of the values to be
                         returned cannot be represented correctly.

                         The request argument is F_GETLK, F_SETLK,
                         or F_SETLKW and the smallest or, if l_
                         len is nonzero, the largest offset of any
                         byte in the requested segment cannot be
                         represented correctly in an object of type
                         off_t.

                      o  EINTR - The request argument is F_SETLKW,
                         and the function was interrupted by a
                         signal.

                      o  ENOLCK - The request argument is F_SETLK or
                         F_SETLKW, and satisfying the lock or unlock
                         request would exceed the configurable
                         system limit of NLOCK_RECORD.

                      o  ENOMEM - The system was unable to allocate
                         memory for the requested file descriptor.
 

2  fcvt
   Converts its argument to a null-terminated string of ASCII digits
   and returns the address of the string. The string is stored in a
   thread-specific location created by the Compaq C RTL.

   Format

     #include  <stdlib.h>

     char *fcvt  (double value, int ndigits, int *decpt, int *sign);
 

3  Arguments
 

value

   An object of type double that is converted to a null-terminated
   string of ASCII digits.
 

ndigits

   The number of ASCII digits after the decimal point to be used in
   the converted string.
 

decpt

   The position of the decimal point relative to the first character
   in the returned string. The returned string does not contain the
   actual decimal point. A negative int value means that the decimal
   point is decpt number of spaces to the left of the returned
   digits (the spaces are filled with zeros). A 0 value means that
   the decimal point is immediately to the left of the first digit
   in the returned string.
 

sign

   An integer value that indicates whether the value argument is
   positive or negative. If value is negative, the fcvt function
   places a nonzero value at the address specified by sign.
   Otherwise, the functions assign 0 to the address specified by
   sign.
 

3  Description
   The fcvt function converts value to a null-terminated string and
   returns a pointer to it. The resulting low-order digit is rounded
   to the correct digit for outputting ndigits digits in C F-format.
   The decpt argument is assigned the position of the decimal point
   relative to the first character in the string.

   In C F-format, ndigits is the number of digits desired after the
   decimal point. Very large numbers produce a very long string of
   digits before the decimal point, and ndigit of digits after the
   decimal point. For large numbers, it is preferable to use the
   gcvt or ecvt function so that E-format is used.

   Repeated calls to the fcvt function overwrite any existing
   string.

   The ecvt, fcvt, and gcvt functions represent the following
   special values specified in the IEEE Standard for floating-point
   arithmetic:

   Value         Representation

   Quiet NaN     NaNQ
   Signalling    NaNS
   NaN
   +Infinity     Infinity
   -Infinity     -Infinity

   The sign associated with each of these values is stored into the
   sign argument. In IEEE floating-point representation, a value
   of 0 (zero) can be positive or negative, as set by the sign
   argument.

   See also gcvt and ecvt.
 

3  Return_Value

   x                  A pointer to the converted string.
 

2  fdim
   Determines the positive difference between its arguments.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double fdim  (double x, double y);

     float fdimf  (float x, float y);

     long double fdiml  (long double x, long double y);
 

3  Argument
 

x

   A real value.
 

y

   A real value.
 

3  Description
   The fdim functions determine the positive difference between
   their arguments. If x is greater than y, x - y is returned. If x
   is less than or equal to y, +0 is returned.
 

3  Return_Values

   n                  Upon success, the positive difference value.
   HUGE_VAL           If x - y is positive and overflows; errno is
                      set to ERANGE.
   0                  If x - y is positive and underflows; errno is
                      set to ERANGE.
   NaN                x or y is NaN; errno is set to EDOM.
 

2  fdopen
   Associates a file pointer with a file descriptor returned by an
   open, creat, dup, dup2, or pipe function.

   Format

     #include  <stdio.h>

     FILE *fdopen  (int file_desc, char *a_mode);
 

3  Arguments
 

file_desc

   The file descriptor returned by open, creat, dup, dup2, or pipe.
 

a_mode

   The access mode indicator. See the fopen function for a
   description. Note that the access mode specified must agree
   with the mode used to originally open the file. This includes
   binary/text access mode ("b" mode on fdopen and the "ctx=bin"
   option on creat or open).
 

3  Description
   The fdopen function allows you to access a file, originally
   opened by one of the UNIX I/O functions, with Standard I/O
   functions. Ordinarily, a file can be accessed by either a file
   descriptor or by a file pointer, but not both, depending on the
   way you open it.
 

3  Return_Values

   pointer            Indicates that the operation has succeeded.
   NULL               Indicates that an error has occurred.
 

2  feof
   Tests a file to see if the end-of-file has been reached.

   Format

     #include  <stdio.h>

     int feof  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Return_Values

   nonzero integer    Indicates that the end-of-file has been
                      reached.
   0                  Indicates that the end-of-file has not been
                      reached.
 

2  feof_unlocked
   Same as feof, except used only within a scope protected by
   flockfile and funlockfile.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     int feof_unlocked  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The reentrant version of the feof function is locked against
   multiple threads calling it simultaneously. This incurs overhead
   to ensure integrity of the stream. The unlocked version of this
   call, feof_unlocked can be used to avoid the overhead. The feof_
   unlocked function is functionally identical to the feof function,
   except that it is not required to be implemented in a thread-
   safe manner. The feof_unlocked function can be safely used only
   within a scope that is protected by the flockfile and funlockfile
   functions used as a pair. The caller must ensure that the stream
   is locked before feof_unlocked is used.

   See also flockfile, ftrylockfile, and funlockfile.
 

3  Return_Values

   nonzero integer    Indicates end-of-file has been reached.
   0                  Indicates end-of-file has not been reached.
 

2  ferror
   Returns a nonzero integer if an error occurred while reading or
   writing a file.

   Format

     #include  <stdio.h>

     int ferror  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   A call to ferror continues to return a nonzero integer until the
   file is closed or until clearerr is called.
 

3  Return_Values

   0                  Indicates success.
   nonzero integer    Indicates that an error has occurred.
 

2  ferror_unlocked
   Same as ferror, except used only within a scope protected by
   flockfile and funlockfile.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     int ferror_unlocked  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The reentrant version of the ferror function is locked against
   multiple threads calling it simultaneously. This incurs overhead
   to ensure integrity of the stream. The unlocked version of this
   call, ferror_unlocked can be used to avoid the overhead. The
   ferror_unlocked function is functionally identical to the ferror
   function, except that it is not required to be implemented in a
   thread-safe manner. The ferror_unlocked function can be safely
   used only within a scope that is protected by the flockfile and
   funlockfile functions used as a pair. The caller must ensure that
   the stream is locked before ferror_unlocked is used.

   See also flockfile, ftrylockfile, and funlockfile.
 

3  Return_Values

   0                  Indicates success.
   nonzero integer    Indicates that an error has occurred.
 

2  fflush
   Writes out any buffered information for the specified file.

   Format

     #include  <stdio.h>

     int fflush  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer. If this argument is a NULL pointer, all buffers
   associated with all currently open files are flushed.
 

3  Description
   The output files are normally buffered only if they are not
   directed to a terminal, except for stderr, which is not buffered
   by default.

   The fflush function flushes the Compaq C RTL buffers. However,
   RMS has its own buffers. The fflush function does not guarantee
   that the file will be written to disk. (See the description of
   fsync for a way to flush buffers to disk.)

   If the file pointed to by file_ptr was opened in record mode
   and if there is unwritten data in the buffer, then fflush always
   generates a record.
 

3  Return_Values

   0                  Indicates that the operation is successful.
   EOF                Indicates that the buffered data cannot be
                      written to the file, or that the file control
                      block is not associated with an output file.
 

2  ffs
   Finds the index of the first bit set in a string.

   Format

     #include  <strings.h>

     int ffs  (int iteger);
 

3  Argument
 

integer

   The integer to be examined for the first bit set.
 

3  Description
   The ffs function finds the first bit set (beginning with the
   least significant bit) and returns the index of that bit. Bits
   are numbered starting at 1 (the least significant bit).
 

3  Return_Values

   x                  The index of the first bit set.
   0                  If index is 0.
 

2  fgetc
   Returns the next character from a specified file.

   Format

     #include  <stdio.h>

     int fgetc  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A pointer to the file to be accessed.
 

3  Description
   The fgetc function returns the next character from the specified
   file.

   Compiling with the __UNIX_PUTC macro defined enables an
   optimization that uses a faster, inlined version of this
   function.

   See also the fgetc_unlocked function and the getc macro.
 

3  Return_Values

   x                  The returned character.
   EOF                Indicates the end-of-file or an error.
 

2  fgetc_unlocked
   Same as the fgetc function, except used only within a scope
   protected by flockfile and funlockfile.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     int fgetc_unlocked  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The reentrant version of the fgetc function is locked against
   multiple threads calling it simultaneously. This incurs overhead
   to ensure integrity of the stream. The unlocked version of this
   call, fgetc_unlocked can be used to avoid the overhead. The
   fgetc_unlocked function is functionally identical to the fgetc
   function, except that fgetc_unlocked can be safely used only
   within a scope that is protected by the flockfile and funlockfile
   functions used as a pair. The caller must ensure that the stream
   is locked before fgetc_unlocked is used.

   Compiling with the __UNIX_PUTC macro defined enables an
   optimization that uses a faster, inlined version of this
   function.

   See also getc_unlocked, flockfile, ftrylockfile, and funlockfile.
 

3  Return_Values

   n                  The returned character.
   EOF                Indicates the end-of-file or an error.
 

2  fgetname
   Returns the file specification associated with a file pointer.

   Format

     #include  <stdio.h>

     char *fgetname  (FILE *file_ptr, char *buffer, . . . );
 

3  Function_Variants
   The fgetname function has variants named _fgetname32 and _
   fgetname64 for use with 32-bit and 64-bit pointer sizes,
   respectively.
 

3  Arguments
 

file_ptr

   A file pointer.
 

buffer

   A pointer to a character string that is large enough to hold the
   file specification.
 

 . . .

   An optional additional argument that can be either 1 or 0. If you
   specify 1, the fgetname function returns the file specification
   in OpenVMS format. If you specify 0, fgetname returns the file
   specification in UNIX style format. If you do not specify this
   argument, fgetname returns the filename according to your current
   command language interpreter.
 

3  Description
   The fgetname function places the file specification at the
   address given in the buffer. The buffer should be an array large
   enough to contain a fully qualified file specification (the
   maximum length is 256 characters).
 

3  Return_Values

   n                  The address of the buffer.
   0                  Indicates an error.
 

3  Restriction
   The fgetname function is specific to the Compaq C RTL and is not
   portable.
 

2  fgetpos
   Stores the current file position for a given file.

   Format

     #include  <stdio.h>

     int fgetpos  (FILE *stream, fpos_t *pos);
 

3  Arguments
 

stream

   A file pointer.
 

pos

   A pointer to an implementation-defined structure. The fgetpos
   function fills this structure with information that can be used
   on subsequent calls to fsetpos.
 

3  Description
   The fgetpos function stores the current value of the file
   position indicator for the stream pointed to by stream into the
   object pointed to by pos.
 

3  Return_Values

   0                  Indicates successful completion.
   -1                 Indicates that there are errors.
 

3  Example

       #include <stdio.h>
       #include <stdlib.h>

       main()
       {
           FILE *fp;
           int stat,
               i;
           int character;
           char ch,
                c_ptr[130],
                d_ptr[130];
           fpos_t posit;

           /* Open a file for writing.  */

           if ((fp = fopen("file.dat", "w+")) == NULL) {
               perror("open");
               exit(1);
           }

          /* Get the beginning position in the file.  */

           if (fgetpos(fp, &posit) != 0)
               perror("fgetpos");

           /* Write some data to the file. */

           if (fprintf(fp, "this is a test\n") == 0) {
               perror("fprintf");
               exit(1);
           }

           /* Set the file position back to the beginning. */

           if (fsetpos(fp, &posit) != 0)
               perror("fsetpos");

           fgets(c_ptr, 130, fp);
           puts(c_ptr);        /* Should be "this is a test."  */

           /* Close the file. */

           if (fclose(fp) != 0) {
               perror("close");
               exit(1);
           }

       }
 

2  fgets
   Reads a line from the specified file, up to one less than the
   specified maximum number of characters or up to and including the
   new-line character, whichever comes first. The function stores
   the string in str.

   Format

     #include  <stdio.h>

     char *fgets  (char *str, int maxchar, FILE *file_ptr);
 

3  Function_Variants
   The fgets function has variants named _fgets32 and _fgets64 for
   use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

str

   A pointer to a character string that is large enough to hold the
   information fetched from the file.
 

maxchar

   The maximum number of characters to fetch.
 

file_ptr

   A file pointer.
 

3  Description
   The fgets function terminates the line with a null character
   (\0). Unlike gets, fgets places the new-line character that
   terminates the input line into the user buffer if more than
   maxchar characters have not already been fetched.

   When the file pointed to by file_ptr is opened in record
   mode, fgets treats the end of a record the same as a new-line
   character, so it reads up to and including a new-line character
   or to the end of the record.
 

3  Return_Values

   x                  Pointer to str.
   NULL               Indicates the end-of-file or an error. The
                      contents of str are undefined if a read error
                      occurs.
 

3  Example

       #include <stdio.h>
       #include <stdlib.h>
       #include <unixio.h>

       main()
       {
           FILE *fp;
           char c_ptr[130];

           /* Create a dummy data file  */

           if ((fp = fopen("file.dat", "w+")) == NULL) {
               perror("open");
               exit(1);
           }

           fprintf(fp, "this is a test\n") ;
           fclose(fp) ;

           /* Open a file with some data -"this is a test"   */

           if ((fp = fopen("file.dat", "r+")) == NULL) {
              perror("open error") ;
               exit(1);
           }

           fgets(c_ptr, 130, fp);
           puts(c_ptr);        /* Display what fgets got.  */
           fclose(fp);

           delete("file.dat") ;
       }
 

2  fgetwc
   Reads the next character from a specified file, and converts it
   to a wide-character code.

   Format

     #include  <wchar.h>

     wint_t fgetwc  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A pointer to the file to be accessed.
 

3  Description
   Upon successful completion, the fgetwc function returns the wide-
   character code read from the file pointed to by file_ptr and
   converted to type wint_t. If the file is at end-of-file, the
   end-of-file indicator is set, and WEOF is returned. If an I/O
   read error occurred, then the error indicator is set, and WEOF is
   returned.

   Applications can use ferror or feof to distinguish between an
   error condition and an end-of-file condition.
 

3  Return_Values

   x                  The wide-character code of the character read.
   WEOF               Indicates the end-of-file or an error. If a
                      read error occurs, the function sets errno to
                      one of the following:

                      o  EALREADY - An operation is already in
                         progress on the same file.

                      o  EBADF - The file descriptor is not valid.

                      o  EILSEQ - Invalid character detected.
 

2  fgetws
   Reads a line of wide characters from a specified file.

   Format

     #include  <wchar.h>

     wchar_t *fgetws  (wchar_t *wstr, int maxchar, FILE *file_ptr);
 

3  Function_Variants
   The fgetws function has variants named _fgetws32 and _fgetws64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

wstr

   A pointer to a wide-character string large enough to hold the
   information fetched from the file.
 

maxchar

   The maximum number of wide characters to fetch.
 

file_ptr

   A file pointer.
 

3  Description
   The fgetws function reads wide characters from the specified file
   and stores them in the array pointed to by wstr. The function
   reads up to maxchar-1 characters or until the new-line character
   is read, converted, and transferred to wstr, or until an end-
   of-file condition is encountered. The function terminates the
   line with a null wide character. fgetws places the new-line that
   terminates the input line into the user buffer, unless maxchar
   characters have already been fetched.
 

3  Return_Values

   x                  Pointer to wstr.
   NULL               Indicates the end-of-file or an error. The
                      contents of wstr are undefined if a read
                      error occurs. If a read error occurs, the
                      function sets errno. For a list of possible
                      errno values, see fgetwc.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <locale.h>
       #include <wchar.h>

       main()
       {
           wchar_t wstr[80],
                  *ret;
           FILE *fp;

           /* Create a dummy data file  */

           if ((fp = fopen("file.dat", "w+")) == NULL) {
               perror("open");
               exit(1);
           }

           fprintf(fp, "this is a test\n") ;
           fclose(fp) ;

          /* Open a test file containing : "this is a test" */

           if ((fp = fopen("file.dat", "r")) == (FILE *) NULL) {
               perror("File open error");
               exit(EXIT_FAILURE);
           }

           ret = fgetws(wstr, 80, fp);
           if (ret == (wchar_t *) NULL) {
               perror("fgetws failure");
               exit(EXIT_FAILURE);
           }

           fputws(wstr, stdout);
           fclose(fp);
           delete("file.dat");
       }
 

2  fileno
   Returns the file descriptor associated with the specified file
   pointer.

   Format

     #include  <stdio.h>

     int fileno  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   If you are using version 5.2 or lower of the C compiler, undefine
   the fileno macro:

   #if defined(fileno)
   #undef fileno
   #endif
 

3  Return_Values

   x                  Integer file descriptor.
   -1                 Indicates an error.
 

2  finite
   Returns the integer value 1 (True) when its argument is a finite
   number, or 0 (False) if not.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     int finite  (double x);

     int finitef  (float x);

     int double finitel  (long double x);
 

3  Argument
 

x

   A real value.
 

3  Description
   The finite functions return 1 when -Infinity < x < +Infinity.
   They return 0 when |x| = Infinity, or x is a NaN.
 

2  flockfile
   Locks a stdio stream.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     void flockfile  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The flockfile function locks a stdio stream so that a thread can
   have exclusive use of that stream for multiple I/O operations.
   Use the flockfile function for a thread that wants to ensure
   that the output of several printf functions, for example, is not
   garbled by another thread also trying to use printf.

   File pointers passed are assumed to be valid; flockfile will
   perform locking even on invalid file pointers. Also, the
   funlockfile function will not fail if the calling thread does
   not own a lock on the file pointer passed.

   Matching flockfile and funlockfile calls can be nested. If the
   stream has been locked recursively, it will remain locked until
   the last matching funlockfile is called.

   All C RTL file-pointer I/O functions lock their file pointers as
   if calling flockfile and funlockfile.

   See also ftrylockfile and funlockfile.
 

2  floor
   Returns the largest integer less than or equal to the argument.

   Format

     #include  <math.h>

     double floor  (double x);

     float floorf  (float x); (Integrity servers, Alpha)

     long double floorl  (long double x);

                         (Integrity servers, Alpha)
 

3  Argument
 

x

   A real value.
 

3  Return_Value

   n                  The largest integer less than or equal to the
                      argument.
 

2  fma
   Computes (x * y) + z, rounded as one ternary operation.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double fma  (double x, double y, double z);

     float fmaf  (float x, float y, float z);

     long double fmal  (long double x, long double y, long double z);
 

3  Argument
 

x,y,z

   Real values.
 

3  Description
   The fma functions compute (x * y) + z, rounded as one ternary
   operation: the value is computed as if to infinite precision and
   rounded once to the result format, according to the rounding mode
   characterized by the value of FLT_ROUNDS.
 

3  Return_Values

   n                  Upon success, (x * y) + z, rounded as one
                      ternary operation.
   NaN                x or y is NaN; errno is set to EDOM.
 

2  fmax
   Returns the maximum numeric value of its arguments.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double fmax  (double x, double y);

     float fmaxf  (float x, float y);

     long double fmaxl  (long double x, long double y);
 

3  Argument
 

x

   A real value.
 

y

   A real value.
 

3  Description
   The fmax functions determine the maximum numeric value of their
   arguments. NaN arguments are treated as missing data: if one
   argument is a NaN and the other numeric, then the numeric value
   is returned.
 

3  Return_Values

   n                  Upon success, the maximum numeric value of the
                      arguments. If just one argument is a NaN, the
                      other argument is returned.
   NaN                Both x and y are NaNs.
 

2  fmin
   Returns the minimum numeric value of its arguments.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double fmin  (double x, double y);

     float fminf  (float x, float y);

     long double fminl  (long double x, long double y);
 

3  Argument
 

x

   A real value.
 

y

   A real value.
 

3  Description
   The fmin functions determine the minimum numeric value of their
   arguments. NaN arguments are treated as missing data: if one
   argument is a NaN and the other numeric, then the numeric value
   is returned.
 

3  Return_Values

   n                  Upon success, the minimum numeric value of the
                      arguments. If just one argument is a NaN, the
                      other argument is returned.
   NaN                Both x and y are NaNs.
 

2  fmod
   Computes the floating-point remainder.

   Format

     #include  <math.h>

     double fmod  (double x, double y);

     float fmodf  (float x, float y); (Integrity servers, Alpha)

     long double fmodl  (long double x, long double y);          
                        (Integrity servers, Alpha)
 

3  Arguments
 

x

   A real value.
 

y

   A real value.
 

3  Description
   The fmod functions return the floating-point remainder of the
   first argument divided by the second. If the second argument is
   0, the function returns 0.
 

3  Return_Values

   x                  The value f, which has the same sign as the
                      argument x, such that x == i * y + f for some
                      integer i, where the magnitude of f is less
                      than the magnitude of y.
   0                  Indicates that y is 0.
 

2  fopen
   Opens a file by returning the address of a FILE structure.

   Format

     #include  <stdio.h>

     FILE *fopen  (const char *file_spec, const char *a_mode);   
                  (ANSI C)

     FILE *fopen  (const char *file_spec, const char             
                  *a_mode, . . . ); (DEC C Extension)
 

3  Arguments
 

file_spec

   A character string containing a valid file specification.
 

a_mode

   The access mode indicator. Use one of the following character
   strings: "r", "w", "a", "r+", "w+", "rb", "r+b", "rb+", "wb",
   "w+b", "wb+", "ab", "a+b", "ab+", or "a+".

   These access modes have the following effects:

   o  "r" opens an existing file for reading.

   o  "w" creates a new file, if necessary, and opens the file for
      writing. If the file exists, it creates a new file with the
      same name and a higher version number.

   o  "a" opens the file for append access. An existing file is
      positioned at the end-of-file, and data is written there. If
      the file does not exist, the Compaq C RTL creates it.

   The update access modes allow a file to be opened for both
   reading and writing. When used with existing files, "r+" and
   "a+" differ only in the initial positioning within the file. The
   modes are:

   o  "r+" opens an existing file for read update access. It is
      opened for reading, positioned first at the beginning-of-file,
      but writing is also allowed.

   o  "w+" opens a new file for write update access.

   o  "a+" opens a file for append update access. The file is first
      positioned at the end-of-file (writing). If the file does not
      exist, the Compaq C RTL creates it.

   o  "b" means binary access mode. In this case, no conversion of
      carriage-control information is attempted.
 

 . . .

   Optional file attribute arguments. The file attribute arguments
   are the same as those used in the creat function. For more
   information, see the creat function.
 

3  Description
   If a version of the file exists, a new file created with fopen
   inherits certain attributes from the existing file unless
   those attributes are specified in the fopen call. The following
   attributes are inherited:

      Record format
      Maximum record size
      Carriage control
      File protection

   If you specify a directory in the filename and it is a search
   list that contains an error, Compaq C for OpenVMS Systems
   interprets it as a file open error.

   The file control block can be freed with the fclose function, or
   by default on normal program termination.
 

3  Return_Values

   x                  File pointer.
   NULL               Indicates an error. The constant NULL is
                      defined in the <stdio.h> header file to be
                      the NULL pointer value. The function returns
                      NULL to signal the following errors:

                      o  File protection violations

                      o  Attempts to open a nonexistent file for
                         read access

                      o  Failure to open the specified file
 

2  fp_class
   Determines the class of IEEE floating-point values.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     int fp_class  (double x);

     int fp_classf  (float x);

     int fp_classl  (long double x);
 

3  Argument
 

x

   An IEEE floating-point number.
 

3  Description
   The fp_class functions determine the class of the specified IEEE
   floating-point number, returning a constant from the <fp_class.h>
   header file. They never cause an exception, even for signaling
   NaNs (Not-a-Number). These functions implement the recommended
   class(x) function in the appendix of the IEEE 754-1985 standard
   for binary floating-point arithmetic. The constants in <fp_
   class.h> refer to the following classes of values:

   FP_SNAN           Signaling NaN (Not-a-Number)
   FP_QNAN           Quiet NaN
   FP_POS_INF        +Infinity
   FP_NEG_INF        -Infinity
   FP_POS_NORM       positive normalized
   FP_NEG_NORM       negative normalized
   FP_POS_DENORM     positive denormalized
   FP_NEG_DENORM     negative denormalized
   FP_POS_ZERO       +0.0 (positive zero)
   FP_NEG_ZERO       -0.0 (negative zero)
 

3  Return_Value

   x                  A constant from the <fp_class.h> header file.
 

2  fpathconf
   Retrieves file implementation characteristics.

   Format

     #include  <unistd.h>

     long int fpathconf  (int filedes, int name);
 

3  Arguments
 

filedes

   An open file descriptor.
 

name

   The configuration attribute to query. If this attribute is
   not applicable to the file specified by the filesdes argument,
   fpathconf returns an error.
 

3  Description
   The fpathconf function allows an application to retrieve the
   characteristics of operations supported by the file system
   underlying the filenamed by the filesdes argument. Read, write,
   or execute permission of the named file is not required, but you
   must be able to search all directories in the path leading to the
   file.

   Symbolic values for the name argument are defined in the
   <unistd.h> header file as follows:

   _PC_LINK_MAX   The maximum number of links to the file. If the
                  filedes argument refers to a directory, the value
                  returned applies to the directory itself.
   _PC_MAX_       The maximum number of bytes in a canonical input
   CANON          line. This is applicable only to terminal devices.
   _PC_MAX_       The number of types allowed in an input queue.
   INPUT          This is applicable only to terminal devices.
   _PC_NAME_MAX   Maximum number of bytes in a filename (not
                  including a terminating null). The byte range
                  value is between 13 and 255. This is applicable
                  only to a directory file. The value returned
                  applies to filenames within the directory.
   _PC_PATH_MAX   Maximum number of bytes in a pathname (not
                  including a terminating null). The value is never
                  larger than 65,535. This is applicable only to a
                  directory file. The value returned is the maximum
                  length of a relative pathname when the specified
                  directory is the working directory.
   _PC_PIPE_BUF   Maximum number of bytes guaranteed to be written
                  atomically. This is applicable only to a FIFO. The
                  value returned applies to the referenced object.
                  If the path argument refers to a directory, the
                  value returned applies to any FIFO that exists or
                  can be created within the directory.
   _PC_CHOWN_     The value returned applies to any files (other
   RESTRICTED     than directories) that exist or can be created
                  within the directory. This is applicable only to a
                  directory file.
   _PC_NO_TRUNC   Returns 1 if supplying a component name longer
                  than allowed by NAME_MAX causes an error. Returns
                  0 (zero) if long component names are truncated.
                  This is applicable only to a directory file.
   _PC_VDISABLE   This is always 0 (zero); no disabling character
                  is defined. This is applicable only to a terminal
                  device.
 

3  Return_Values

   x                  The resultant value for the configuration
                      attribute specified in the name argument.
   -1                 Indicates an error; errno is set to one of the
                      following values:

                      o  EINVAL - The name argument specifies an
                         unknown or inapplicable characteristic.

                      o  EBADF - the filedes argument is not a valid
                         file descriptor.
 

2  fprintf
   Performs formatted output to a specified file.

   Format

     #include  <stdio.h>

     int fprintf  (FILE *file_ptr, const char *format_spec, . . . );
 

3  Arguments
 

file_ptr

   A pointer to the file to which the output is directed.
 

format_spec

   A pointer to a character string that contains the format
   specification.
 

 . . .

   Optional expressions whose resultant types correspond to
   conversion specifications given in the format specification.

   If no conversion specifications are given, the output sources can
   be omitted. Otherwise, the function calls must have exactly as
   many output sources as there are conversion specifications, and
   the conversion specifications must match the types of the output
   sources.

   Conversion specifications are matched to output sources in left-
   to-right order. Any excess output sources are ignored.
 

3  Example

     An example of a conversion specification follows:

       #include <stdio.h>

       main()
       {
          int  temp = 4, temp2 = 17;

          fprintf(stdout, "The answers are %d, and %d.", temp, temp2);
       }

     This example outputs the following to the stdout file:

       The answers are 4, and 17.
 

3  Return_Values

   x                  The number of bytes written, excluding the
                      null terminator.
   Negative value     Indicates an error. The function sets errno to
                      one of the following:

                      o  EILSEQ - Invalid character detected.

                      o  EINVAL - Insufficient arguments.

                      o  ENOMEM - Not enough memory available for
                         conversion.

                      o  ERANGE - Floating-point calculations
                         overflow.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This might indicate that conversion to a
                         numeric value failed because of overflow.

                      The function can also set errno to the
                      following as a result of errors returned from
                      the I/O subsystem:

                      o  EBADF - The file descriptor is not valid.

                      o  EIO - I/O error.

                      o  ENOSPC - No free space on the device
                         containing the file.

                      o  ENXIO - Device does not exist.

                      o  EPIPE - Broken pipe.

                      o  ESPIPE - Illegal seek in a file opened for
                         append.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This indicates that an I/O error occurred
                         for which there is no equivalent C error
                         code.
 

2  fputc
   Writes a character to a specified file.

   Format

     #include  <stdio.h>

     int fputc  (int character, FILE *file_ptr);
 

3  Arguments
 

character

   An object of type int.
 

file_ptr

   A file pointer.
 

3  Description
   The fputc function writes a single character to the specified
   file and returns the character.

   Compiling with the __UNIX_PUTC macro defined enables an
   optimization that uses a faster, inlined version of this
   function.

   See also the fputc_unlocked function and the putc macro.
 

3  Return_Values

   x                  The character written to the file. Indicates
                      success.
   EOF                Indicates an output error.
 

2  fputc_unlocked
   Same as the fputc function, except used only within a scope
   protected by flockfile and funlockfile.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     int fputc_unlocked  (int character, FILE *file_ptr);
 

3  Arguments
 

character

   The character to be written. An object of type int.
 

file_ptr

   A file pointer.
 

3  Description
   See the putc_unlocked macro.

   Compiling with the __UNIX_PUTC macro defined enables an
   optimization that uses a faster, inlined version of this
   function.

   See also flockfile, ftrylockfile, and funlockfile.
 

3  Return_Values

   n                  The returned character.
   EOF                Indicates the end-of-file or an error.
 

2  fputs
   Writes a character string to a file without copying the string's
   null terminator (\0).

   Format

     #include  <stdio.h>

     int fputs  (const char *str, FILE *file_ptr);
 

3  Arguments
 

str

   A pointer to a character string.
 

file_ptr

   A file pointer.
 

3  Description
   Unlike puts, the fputs function does not append a new-line
   character to the output string.

   See also puts.
 

3  Return_Values

   Nonnegative value  Indicates success.
   EOF                Indicates an error.
 

2  fputwc
   Converts a wide character to its corresponding multibyte value,
   and writes the result to a specified file.

   Format

     #include  <wchar.h>

     wint_t fputwc  (wint_t wc, FILE *file_ptr);
 

3  Arguments
 

wc

   An object of type wint_t.
 

file_ptr

   A file pointer.
 

3  Description
   The fputwc function writes a wide character to a file and returns
   the character.

   See also putwc.
 

3  Return_Values

   x                  The character written to the file. Indicates
                      success.
   WEOF               Indicates an output error. The function sets
                      errno to the following:

                      o  EILSEQ - Invalid wide-character code
                         detected.

                      The function can also set errno to the
                      following as a result of errors returned from
                      the I/O subsystem:

                      o  EBADF - The file descriptor is not valid.

                      o  EIO - I/O error.

                      o  ENOSPC - No free space on the device
                         containing the file.

                      o  ENXIO - Device does not exist.

                      o  EPIPE - Broken pipe.

                      o  ESPIPE - Illegal seek in a file opened for
                         append.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This indicates that an I/O error occurred
                         for which there is no equivalent C error
                         code.
 

2  fputws
   Writes a wide-character string to a file without copying the
   null-terminating character.

   Format

     #include  <wchar.h>

     int fputws  (const wchar_t *wstr, FILE *file_ptr);
 

3  Arguments
 

wstr

   A pointer to a wide-character string.
 

file_ptr

   A file pointer.
 

3  Description
   The fputws function converts the specified wide-character string
   to a multibyte character string and writes it to the specified
   file. The function does not append a terminating null byte
   corresponding to the null wide-character to the output string.
 

3  Return_Values

   Nonnegative value  Indicates success.
   -1                 Indicates an error. The function sets errno.
                      For a list of the values, see fputwc.
 

2  fread
   Reads a specified number of items from the file.

   Format

     #include  <stdio.h>

     size_t fread  (void *ptr, size_t size_of_item, size_t       
                   number_items, FILE *file_ptr);
 

3  Arguments
 

ptr

   A pointer to the location, within memory, where you place the
   information being read. The type of the object pointed to is
   determined by the type of the item being read.
 

size_of_item

   The size of the items being read, in bytes.
 

number_items

   The number of items to be read.
 

file_ptr

   A pointer that indicates the file from which the items are to be
   read.
 

3  Description
   The type size_t is defined in the header file <stdio.h> as
   follows:

   typedef unsigned int size_t

   The reading begins at the current location in the file. The items
   read are placed in storage beginning at the location given by
   the first argument. You must also specify the size of an item, in
   bytes.

   If the file pointed to by file_ptr was opened in record mode,
   fread will read size_of_item multiplied by number_items bytes
   from the file. That is, it does not necessarily read number_items
   records.
 

3  Return_Values

   n                  The number of bytes read divided by size_of_
                      item.
   0                  Indicates the end-of-file or an error.
 

2  free
   Makes available for reallocation the area allocated by a previous
   calloc, malloc, or realloc call.

   Format

     #include  <stdlib.h>

     void free  (void *ptr);
 

3  Argument
 

ptr

   The address returned by a previous call to malloc, calloc, or
   realloc. If ptr is a NULL pointer, no action occurs.
 

3  Description
   The ANSI C standard defines free as not returning a value;
   therefore, the function prototype for free is declared with
   a return type of void. However, since a free can fail, and
   since previous versions of the Compaq C RTL have declared free
   to return an int, the implementation of free does return 0 on
   success and -1 on failure.
 

2  freopen
   Substitutes the filenamed by a file specification for the open
   file addressed by a file pointer. The latter file is closed.

   Format

     #include  <stdio.h>

     FILE *freopen  (const char *file_spec, const char *a_mode, FILE
                    *file_ptr, . . . );
 

3  Arguments
 

file_spec

   A pointer to a string that contains a valid OpenVMS or UNIX
   style file specification. After the function call, the given
   file pointer is associated with this file.
 

a_mode

   The access mode indicator. See the fopen function for a
   description.
 

file_ptr

   A file pointer.
 

 . . .

   Optional file attribute arguments. The file attribute arguments
   are the same as those used in the creat function.
 

3  Description
   The freopen function is typically used to associate one of the
   predefined names stdin, stdout, or stderr with a file.
 

3  Return_Values

   file_ptr           The file pointer, if freopen is successful.
   NULL               Indicates an error.
 

2  frexp
   Calculates the fractional and exponent parts of a floating-point
   value.

   Format

     #include  <math.h>

     double frexp  (double value, int *eptr);

     float frexpf  (float value, int *eptr);                        
                   (Integrity servers, Alpha)
                                                                    
     long double frexpl (long double value, int *eptr);
                         (Integrity servers, Alpha)
 

3  Arguments
 

value

   A floating-point number of type double, float, or long double.
 

eptr

   A pointer to an int where frexp places the exponent.
 

3  Description
   The frexp functions break the floating-point number (value) into
   a normalized fraction and an integral power of 2, as follows:

   value = fraction * (2exp)

   The fractional part is returned as the return value. The exponent
   is placed in the integer variable pointed to by eptr.
 

3  Example

       #include <math.h>

       main ()
       {
          double val = 16.0, fraction;
          int exp;

          fraction = frexp(val, &exp);
          printf("fraction = %f\n",fraction);
          printf("exp = %d\n",exp);

       }

     In this example, frexp converts the value 16 to .5 * 2 . The

     example produces the following output:

       fraction = 0.500000
       exp = 5

     |value| = Infinity or NaN is an invalid argument.
 

3  Return_Values

   x                  The fractional part of value.
   0                  Both parts of the result are 0.
   NaN                If value is NaN, NaN is returned, errno
                      is set to EDOM, and the value of *eptr is
                      unspecified.
   value              If |value| = Infinity, value is returned,
                      errno is set to EDOM, and the value of *eptr
                      is unspecified.
 

2  fscanf
   Performs formatted input from a specified file, interpreting it
   according to the format specification.

   Format

     #include  <stdio.h>

     int fscanf  (FILE *file_ptr, const char *format_spec, . . . );
 

3  Arguments
 

file_ptr

   A pointer to the file that provides input text.
 

format_spec

   A pointer to a character string that contains the format
   specification.
 

 . . .

   Optional expressions whose results correspond to conversion
   specifications given in the format specification.

   If no conversion specifications are given, you can omit the input
   pointers. Otherwise, the function calls must have exactly as
   many input pointers as there are conversion specifications, and
   the conversion specifications must match the types of the input
   pointers.

   Conversion specifications are matched to input sources in left-
   to-right order. Excess input pointers, if any, are ignored.
 

3  Description
   An example of a conversion specification follows:

   #include <stdio.h>

   main ()
   {
      int   temp, temp2;

      fscanf(stdin, "%d %d", &temp, &temp2);
      printf("The answers are %d, and %d.", temp, temp2);
   }

   Consider a file, designated by stdin, with the following
   contents:

   4 17

   The example conversion specification produces the following
   result:

   The answers are 4, and 17.
 

3  Return_Values

   x                  The number of successfully matched and
                      assigned input items.
   EOF                Indicates that the end-of-file was encountered
                      or a read error occurred. If a read error
                      occurs, the function sets errno to one of the
                      following:

                      o  EILSEQ - Invalid character detected.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This can indicate that conversion to a
                         numeric value failed due to overflow.

                      The function can also set errno to the
                      following as a result of errors returned from
                      the I/O subsystem:

                      o  EBADF - The file descriptor is not valid.

                      o  EIO - I/O error.

                      o  ENXIO - Device does not exist.

                      o  EPIPE - Broken pipe.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This indicates that an I/O error occurred
                         for which there is no equivalent C error
                         code.
 

2  fseek
   Positions the file to the specified byte offset in the file.

   Format

     #include  <stdio.h>

     int fseek  (FILE *file_ptr, long int offset, int direction);
 

3  Arguments
 

file_ptr

   A file pointer.
 

offset

   The offset, specified in bytes.
 

direction

   An integer indicating the position to which the offset is added
   to calculate the new position. The new position is the beginning
   of the file if direction is SEEK_SET, the current value of the
   file position indicator if direction is SEEK_CUR, or end-of-file
   if direction is SEEK_END.
 

3  Description
   The fseek function can position a fixed-length record-access
   file with no carriage control or a stream-access file on any
   byte offset, but can position all other files only on record
   boundaries.

   The available Standard I/O functions position a variable-length
   or VFC record file at its first byte, at the end-of-file, or on
   a record boundary. Therefore, the arguments given to fseek must
   specify any of the following:

   o  The beginning or end of the file

   o  A 0 offset from the current position (an arbitrary record
      boundary)

   o  The position returned by a previous, valid ftell call

   See the fgetpos and fsetpos functions for a portable way to seek
   to arbitrary locations with these types of record files.

                                CAUTION

      If, while accessing a stream file, you seek beyond the
      end-of-file and then write to the file, the fseek function
      creates a hole by filling the skipped bytes with zeros.

      In general, for record files, fseek should only be directed
      to an absolute position that was returned by a previous
      valid call to ftell, or to the beginning or end of a file.
      If a call to fseek does not satisfy these conditions, the
      results are unpredictable.

   See also open, creat, dup, dup2, and lseek.
 

3  Return_Values

   0                  Indicates successful seeks.
   -1                 Indicates improper seeks.
 

2  fseeko
   Positions the file to the specified byte offset in the file.
   Equivalent to fseek.

   Format

     #include  <stdio.h>

     int fseeko  (FILE *file_ptr, off_t offset, int direction);
 

3  Arguments
 

file_ptr

   A file pointer.
 

offset

   The offset, specified in bytes. The off_t data type is either a
   32-bit or 64-bit integer. The 64-bit interface allows for file
   sizes greater than 2 GB, and can be selected at compile time by
   defining the _LARGEFILE feature-test macro as follows:

   CC/DEFINE=_LARGEFILE
 

direction

   An integer indicating the position to which the offset is added
   to calculate the new position. The new position is the beginning
   of the file if direction is SEEK_SET, the current value of the
   file position indicator if direction is SEEK_CUR, or end-of-file
   if direction is SEEK_END.
 

3  Description
   The fseeko function is identical to the fseek function, except
   that the offset argument is of type off_t instead of long int.
 

2  fsetpos
   Sets the file position indicator for a given file.

   Format

     #include  <stdio.h>

     int fsetpos  (FILE *stream, const fpos_t *pos);
 

3  Arguments
 

stream

   A file pointer.
 

pos

   A pointer to an implementation-defined structure. The fgetpos
   function fills this structure with information that can be used
   on subsequent calls to fsetpos.
 

3  Description
   Call the fgetpos function before using the fsetpos function.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error.
 

2  fstat
   Accesses information about the file specified by the file
   descriptor.

   Format

     #include  <stat.h>

     int fstat  (int file_desc, struct stat *buffer);
 

3  Function_Variants
   Compiling with the _DECC_V4_SOURCE and _VMS_V6_SOURCE feature-
   test macros defined enables a local-time-based entry point to the
   fstat function that is equivalent to the behavior before OpenVMS
   Version 7.0.
 

3  Arguments
 

file_desc

   A file descriptor.
 

buffer

   A pointer to a structure of type stat_t, which is defined in the
   <stat.h> header file. The argument receives information about
   that particular file. The members of the structure pointed to by
   buffer are:

   Member       Type        Definition

   st_dev       dev_t       Pointer to a physical device name
   st_ino[3]    ino_t       Three words to receive the file ID
   st_mode      mode_t      File "mode" (prot, dir, . . . )
   st_nlink     nlink_t     For UNIX system compatibility only
   st_uid       uid_t       Owner user ID
   st_gid       gid_t       Group member: from st_uid
   st_rdev      dev_t       UNIX system compatibility - always 0
   st_size      off_t       File size, in bytes. For st_size to
                            report a correct value, you need to
                            flush both the C RTL and RMS buffers.
   st_atime     time_t      File access time; always the same as
                            st_mtime
   st_mtime     time_t      Last modification time
   st_ctime     time_t      File creation time
   st_fab_rfm   char        Record format
   st_fab_rat   char        Record attributes
   st_fab_fsz   char        Fixed header size
   st_fab_mrs   unsigned    Record size

   The types dev_t, ino_t, off_t, mode_t, nlink_t, uid_t, gid_t, and
   time_t, are defined in the <stat.h> header file. However, when
   compiling for compatibility (/DEFINE=_DECC_V4_SOURCE), only dev_
   t, ino_t, and off_t are defined.

   The off_t data type is either a 32-bit or 64-bit integer. The 64-
   bit interface allows for file sizes greater than 2 GB, and can be
   selected at compile time by defining the _LARGEFILE feature-test
   macro as follows:

   CC/DEFINE=_LARGEFILE

   As of OpenVMS Version 7.0, times are given in seconds since the
   Epoch (00:00:00 GMT, January 1, 1970).

   The st_mode structure member is the status information mode and
   is defined in the <stat.h> header file. The st_mode bits follow:

   Bits     Constant  Definition

   0170000  S_IFMT    Type of file
   0040000  S_IFDIR   Directory
   0020000  S_IFCHR   Character special
   0060000  S_IFBLK   Block special
   0100000  S_IFREG   Regular
   0030000  S_IFMPC   Multiplexed char special
   0070000  S_IFMPB   Multiplexed block special
   0004000  S_ISUID   Set user ID on execution
   0002000  S_ISGID   Set group ID on execution
   0001000  S_ISVTX   Save swapped text even after use
   0000400  S_IREAD   Read permission, owner
   0000200  S_IWRITE  Write permission, owner
   0000100  S_IEXEC   Execute/search permission, owner
 

3  Description
   The fstat function does not work on remote network files.

   Be aware that for the stat_t structure member st_size to report a
   correct value, you need to flush both the C RTL and RMS buffers.

                    NOTE (Integrity servers, Alpha)

      On OpenVMS Alpha and Integrity server systems, the stat,
      fstat, utime, and utimes functions have been enhanced to
      take advantage of the new file-system support for POSIX
      compliant file timestamps.

      This support is available only on ODS-5 devices on OpenVMS
      Alpha and Integrity servers systems beginning with a version
      of OpenVMS Alpha after Version 7.3.

      Before this change, the stat and fstat functions were
      setting the values of the st_ctime, st_mtime, and st_atime
      fields based on the following file attributes:

         st_ctime - ATR$C_CREDATE (file creation time)
         st_mtime - ATR$C_REVDATE (file revision time)
         st_atime - was always set to st_mtime because no support
         for file access time was available

      Also, for the file-modification time, utime and utimes were
      modifying the ATR$C_REVDATE file attribute, and ignoring the
      file-access-time argument.

      After the change, for a file on an ODS-5 device, the stat
      and fstat functions set the values of the st_ctime, st_
      mtime, and st_atime fields based on the following new file
      attributes:

         st_ctime - ATR$C_ATTDATE (last attribute modification
         time)
         st_mtime - ATR$C_MODDATE (last data modification time)
         st_atime - ATR$C_ACCDATE (last access time)

      If ATR$C_ACCDATE is zero, as on an ODS-2 device, the stat
      and fstat functions set st_atime to st_mtime.

      For the file-modification time, the utime and utimes
      functions modify both the ATR$C_REVDATE and ATR$C_MODDATE
      file attributes. For the file-access time, these functions
      modify the ATR$C_ACCDATE file attribute. Setting the ATR$C_
      MODDATE and ATR$C_ACCDATE file attributes on an ODS-2 device
      has no effect.

      For compatibility, the old behavior of stat, fstat, utime,
      and utimes remains the default, regardless of the kind of
      device.

      The new behavior must be explicitly enabled at run time
      by defining the DECC$EFS_FILE_TIMESTAMPS logical name to
      "ENABLE" before invoking the application. Setting this
      logical does not affect the behavior of stat, fstat, utime
      and utimes for files on an ODS-2 device.
 

3  Return_Values

   0                  Indicates successful completion.
   -1                 Indicates an error other than a protection
                      violation.
   -2                 Indicates a protection violation.
 

2  fstatvfs
   Gets information about a device containing the specified file.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <statvfs.h>

     int fstatvfs  (int filedes, struct statvfs *buffer);
 

3  Arguments
 

filedes

   File descriptor obtained from a successful open or fcntl function
   call.
 

buffer

   Pointer to a statvfs structure to hold the returned information.
 

3  Description
   The fstatvfs function returns descriptive information about the
   device containing the specified file. Read, write, or execute
   permission of the specified file is not required. The returned
   information is in the format of a statvfs structure, which is
   defined in the <statvfs.h> header file and contains the following
   members:

      unsigned long f_bsize - Preferred block size.

      unsigned long f_frsize - Fundamental block size.

      fsblkcnt_t f_blocks - Total number of blocks in units of f_
      frsize.

      fsblkcnt_t f_bfree - Total number of free blocks. If f_bfree
      would assume a meaningless value due to the misreporting of
      free block count by $GETDVI for a DFS disk, then f_bfree is
      set to the maximum block count.

      fsblkcnt_t f_bavail - Number of free blocks available. Set to
      the unused portion of the caller's disk quota.

      fsfilcnt_t f_files - Total file (inode) count.

      fsfilcnt_t f_ffree - Free file (inode) count. For OpenVMS
      systems, this value is calculated as freeblocks/clustersize.

      fsfilcnt_t f_favail - Free file (inode) count nonprivileged.
      Set to f_ffree.

      unsigned long f_fsid - File system identifier. This identifier
      is based on the allocation-class device name. This gives a
      unique value based on device, as long as the device is locally
      mounted.

      unsigned long f_flag - Bit mask representing one or more of
      the following flags:

         ST_RONLY - The volume is read-only.
         ST_NOSUID - The volume has protected subsystems enabled.

      unsigned long f_namemax - Maximum length of a filename.
      char f_basetype[64] - Device-type name.
      char f_fstr[64] - Logical volume name.
      char __reserved[64] - Media type name.

   Upon successful completion, fstatvfs returns 0 (zero). Otherwise,
   it returns -1 and sets errno to indicate the error.

   See also statvfs.
 

3  Return_Value

   0                  Successful completion.
   -1                 Indicates an error. errno is set to one of the
                      following:

                      o  EBADF - The file descriptor parameter
                         contains an invalid value.

                      o  EIO - An I/O error occurred while reading
                         the device.

                      o  EINTR - A signal was intercepted during
                         execution of the function.

                      o  EOVERFLOW - One of the values to be
                         returned cannot be represented correctly
                         in the structure pointed to by buffer.
 

2  fsync
   Flushes data all the way to the disk.

   Format

     #include  <unistd.h>

     int fsync  (int fd);
 

3  Argument
 

fd

   A file descriptor corresponding to an open file.
 

3  Description
   The fsync function behaves much like the fflush function. The
   primary difference between the two is that fsync flushes data
   all the way to the disk while fflush flushes data only as far as
   the underlying RMS buffers. Also, with fflush, you can flush all
   buffers at once; with fsync you cannot.
 

3  Return_Values

   0                  Indicates successful completion.
   -1                 Indicates an error.
 

2  ftell
   Returns the current byte offset to the specified stream file.

   Format

     #include  <stdio.h>

     long int ftell  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The ftell function measures the byte offset from the beginning of
   the file.

   For variable-length files, VFC files, or any file with carriage-
   control attributes, if the file is opened in record mode, then
   ftell returns the starting position of the current record, not
   the current byte offset.

   When using record files, the ftell function ignores any
   characters that have been pushed back using either ungetc or
   ungetwc. This behavior does not occur if stream files are being
   used.

   For a portable way to measure the exact offset for any type of
   file, see the fgetpos function.
 

3  Return_Values

   n                  The current offset.
   EOF                Indicates an error.
 

2  ftello
   Returns the current byte offset to the specified stream file.
   This function is equivalent to ftell.

   Format

     #include  <stdio.h>

     off_t ftello  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The ftello function is identical to the ftell function, except
   that the return value is of type off_t instead of long int.

   The off_t data type is either a 64-bit or 32-bit integer. The 64-
   bit interface allows for file sizes greater than 2 GB, and can be
   selected at compile time by defining the _LARGEFILE feature-test
   macro as follows:

   CC/DEFINE=_LARGEFILE
 

2  ftime
   Returns the elapsed time since 00:00:00, January 1, 1970, in the
   structure pointed at by timeptr.

   Format

     #include  <timeb.h>

     int ftime  (struct timeb *timeptr);
 

3  Function_Variants
   Compiling with the _DECC_V4_SOURCE and _VMS_V6_SOURCE feature-
   test macros defined enables a local-time-based entry point to the
   ftime function that is equivalent to the behavior before OpenVMS
   Version 7.0.
 

3  Argument
 

timeptr

   A pointer to the structure timeb_t.
 

3  Description
   The typedef timeb_t refers to the following structure defined in
   the <timeb.h> header file:

   typedef struct timeb
      {
         time_t         time;
         unsigned short millitm;
         short          timezone;
         short          dstflag;
      };

   The member time gives the time in seconds.

   The member millitm gives the fractional time in milliseconds.

   After a call to ftime, the timezone and dstflag members of the
   timeb structure have the values of the global variables timezone
   and dstflag, respectively. See the description of the tzset
   function for timezone and dstflag global variables.
 

3  Return_Values

   0                  Successful execution. The timeb_t structure is
                      filled in.
   -1                 Indicates an error. Failure might indicate
                      that the system's time-differential factor
                      (that is, the difference between the system
                      time and UTC time) is not set correctly.

                      If the value of the SYS$TIMEZONE_DIFFERENTIAL
                      logical is wrong, the function fails with
                      errno set to EINVAL.
 

2  ftok
   Generates a standard interprocess communication key that is
   usable in subsequent calls to semget.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <ipc.h>

     key_t ftok  (const char *path_name, int project_id);
 

3  Argument
 

path_name

   the pathname of an existing file that is accessible to the
   process.
 

project_id

   a value that uniquely identifies a project.
 

3  Description
   The ftok function returns a key, based on the path_name and
   project_id parameters, that is usable in subsequent calls to the
   semget function. The ftok function returns the same key for all
   paths that name the same file, when called with the same project_
   id parameter. Different keys are returned for the same file if
   different project_id parameters are used, or if paths are used
   that name different files existing on the same file system at the
   same time. If a file named by path_name is removed and recreated
   with the same name, the ftok function may return a different key
   than the original one.

   Only the low order 8 bits of project_id are significant. The
   behavior of ftok is unspecified if these bits are 0.

   For maximum portability, project_id must be a single-byte
   character.

   Upon successful completion, the ftok function returns a key.
   Otherwise, it returns the value (key_t)-1 and sets errno to
   indicate the error.
 

3  Return_Values

   n                  Upon successful completion, the ftok function
                      returns a key.
   (key_t)-1          Indicates an error. The function sets errno
                      to:

                      o  EACCESS - Search permission is denied for a
                         component of the path_name parameter.
 

2  ftruncate
   Truncates a file to a specified length.

   Format

     #include  <unistd.h>

     int ftruncate  (int filedes, off_t length);
 

3  Arguments
 

filedes

   The descriptor of a file that must be open for writing.
 

length

   The new length of the file, in bytes. The off_t data type is
   either a 32-bit or 64-bit integer. The 64-bit interface allows
   for file sizes greater than 2 GB, and can be selected at compile
   time by defining the _LARGEFILE feature-test macro as follows:

   CC/DEFINE=_LARGEFILE
 

3  Description
   The ftruncate function truncates a file at the specified
   position. For record files, the position must be a record
   boundary. Also, the files must be local, regular files.

   If the file was previously larger than length, extra data is
   lost. If the file was previously shorter than length, bytes
   between the old and new lengths are read as zeros.
 

3  Return_Values

   0                  Indicates success.
   -1                 An error occurred; errno is set to indicate
                      the error.
 

2  ftrylockfile
   Acquires ownership of a stdio (FILE*) object.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     int ftrylockfile  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The ftrylockfile function is used by a thread to acquire
   ownership of a stdio (FILE*) object, if the object is available.
   The ftrylockfile function is a non-blocking version of flockfile.

   The ftrylockfile function returns zero for success and nonzero to
   indicate that the lock cannot be acquired.

   See also flockfile and funlockfile.
 

3  Return_Values

   0                  Indicates success.
   nonzero            Indicates the lock cannot be acquired.
 

2  ftw
   Walks a file tree.

   Format

     #include  <ftw.h>

     int ftw  (const char *path, int(*function)(const char *, const
              struct stat *, int), int depth);
 

3  Arguments
 

path

   The directory hierarchy to be searched.
 

function

   The function to be invoked for each file in the directory
   hierarchy.
 

depth

   The maximum number of directory streams or file descriptors, or
   both, available for use by ftw. This argument should be in the
   range of 1 to OPEN_MAX.
 

3  Description
   The ftw function recursively searches the directory hierarchy
   that descends from the directory specified by the path argument.
   The path argument can be specified in OpenVMS style or UNIX
   style.

   For each file in the hierarchy, ftw calls the function specified
   by the function argument, passes it a pointer to a null-
   terminated character string containing the name of the file, a
   pointer to a stat structure containing information about the
   file, and an integer.

   The integer identifies the file type. Possible values, defined in
   <ftw.h> are:

   FTW_F          Regular file.
   FTW_D          Directory.
   FTW_DNR        Directory that cannot be read.
   FTW_NS         A file on which stat could not successfully be
                  executed.

   If the integer is FTW_DNR, then the files and subdirectories
   contained in that directory are not processed.

   If the integer is FTW_NS, then the stat structure contents are
   meaningless. For example, a file in a directory for which you
   have read permission but not execute (search) permission can
   cause the function argument to pass FTW_NS.

   The ftw function finishes processing a directory before
   processing any of its files or subdirectories.

   The ftw function continues the search until:

   o  The directory hierarchy specified by the path argument is
      completed.

   o  An invocation of the function specified by the function
      argument returns a nonzero value.

   o  An error (such as an I/O error) is detected within the ftw
      function.

   Because the ftw function is recursive, it is possible for it
   to terminate with a memory fault because of stack overflow when
   applied to very deep file structures.

   The ftw function uses the malloc function to allocate dynamic
   storage during its operation. If ftw is forcibly terminated,
   as with a call to longjmp from the function pointed to by the
   function argument, ftw has no chance to free that storage. It
   remains allocated.

   A safe way to handle interrupts is to store the fact that
   an interrupt has occurred, and arrange to have the function
   specified by the function argument return a nonzero value the
   next time it is called.

                                 NOTES

      o  The ftw function is reentrant; make sure that the
         function supplied as argument function is also reentrant.

      o  The C RTL supports a standard-compliant definition of the
         stat structure and associated definitions. To use them,
         compile your application with the _USE_STD_STAT feature-
         test macro defined. See the <stat.h> header file on your
         system for more information.

      o  The ftw function supports UNIX style path name
         specifications.

   See also malloc, longjump, and stat.
 

3  Return_Values

   0                  Indicates success.
   x                  Indicates that the function specified by
                      the function argument stops its search, and
                      returns the value that was returned by the
                      function.
   -1                 Indicates an error; errno is set to one of the
                      following values:

                      o  EACCES - Search permission is denied for
                         any component of the path argument or read
                         permission is denied for the path argument.

                      o  ENAMETOOLONG - The length of the path
                         string exceeds PATH_MAX, or a pathname
                         component is longer than NAME_MAX while
                         [_POSIX_NO_TRUNC] is in effect.

                      o  ENOENT - The path argument points to the
                         name of a file that does not exist or
                         points to an empty string.

                      o  ENOMEM - There is insufficient memory for
                         this operation.

                      Also, if the function pointed to by the
                      function argument encounters an error, errno
                      can be set accordingly.
 

2  funlockfile
   Unlocks a stdio stream.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     void funlockfile  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The funlockfile function unlocks a stdio stream, causing the
   thread that had been holding the lock to relinquish exclusive use
   of the stream.

   File pointers passed are assumed to be valid; flockfile will
   perform locking even on invalid file pointers. Also, the
   funlockfile function will not fail if the calling thread does
   not own a lock on the file pointer passed.

   Matching flockfile and funlockfile calls can be nested. If the
   stream has been locked recursively, it will remain locked until
   the last matching funlockfile is called.

   All C RTL file-pointer I/O functions lock their file pointers as
   if calling flockfile and funlockfile.

   See also flockfile and ftrylockfile.
 

2  fwait
   Waits for I/O on a specific file to complete.

   Format

     #include  <stdio.h>

     int fwait  (FILE *fp);
 

3  Argument
 

fp

   A file pointer corresponding to an open file.
 

3  Description
   The fwait function is used primarily to wait for completion of
   pending asynchronous I/O.
 

3  Return_Values

   0                  Indicates successful completion.
   -1                 Indicates an error.
 

2  fwide
   Determines and sets the orientation of a stream.

   Format

     #include  <wchar.h>

     int fwide  (FILE *stream, int mode);
 

3  Arguments
 

stream

   A file pointer.
 

mode

   A value that specifies the desired orientation of the stream.
 

3  Description
   The fwide function determines the orientation of the stream
   pointed to by stream and sets the orientation of a nonoriented
   stream according to the mode argument in the following way:

   If the mode
   argument is:     Then the fwide function:

   greater than     makes the stream wide-oriented.
   zero
   less than zero   makes the stream byte-oriented.
   zero             does not alter the orientation of the stream.

   If the orientation of the stream has already been set, fwide does
   not alter it. Because no error status is defined for fwide, the
   calling application should check errno if fwide returns a 0.
 

3  Return_Values

   > 0                After the call, the stream is wide-oriented.
   < 0                After the call, the stream is byte-oriented.
   0                  After the call, the stream has no orientation
                      or a stream argument is invalid; the function
                      sets errno.
 

2  fwprintf
   Writes output to the stream under control of the wide-character
   format string.

   Format

     #include  <wchar.h>

     int fwprintf  (FILE *stream, const wchar_t *format, . . . );
 

3  Arguments
 

stream

   A file pointer.
 

format

   A pointer to a wide-character string containing the format
   specifications.
 

 . . .

   Optional expressions whose resultant types correspond to
   conversion specifications given in the format specification.

   If no conversion specifications are given, the output sources can
   be omitted. Otherwise, the function calls must have exactly as
   many output sources as there are conversion specifications, and
   the conversion specifications must match the types of the output
   sources.

   Conversion specifications are matched to output sources in left-
   to-right order. Any excess output sources are ignored.
 

3  Description
   The fwprintf function writes output to the stream pointed to by
   stream under control of the wide-character string pointed to by
   format, which specifies how to convert subsequent arguments to
   output. If there are insufficient arguments for the format, the
   behavior is undefined. If the format is exhausted while arguments
   remain, the excess arguments are evaluated, but are otherwise
   ignored. The fwprintf function returns when it encounters the end
   of the format string.

   The format argument is composed of zero or more directives that
   include:

   o  Ordinary wide characters (not the percent sign (%))

   o  Conversion specifications
 

3  Return_Values

   n                  The number of wide characters written.
   Negative value     Indicates an error. The function sets errno to
                      one of the following:

                      o  EILSEQ - Invalid character detected.

                      o  EINVAL - Insufficient arguments.

                      o  ENOMEM - Not enough memory available for
                         conversion.

                      o  ERANGE - Floating-point calculations
                         overflow.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This might indicate that conversion to a
                         numeric value failed because of overflow.

                      The function can also set errno to the
                      following as a result of errors returned from
                      the I/O subsystem:

                      o  EBADF - The file descriptor is not valid.

                      o  EIO - I/O error.

                      o  ENOSPC - No free space on the device
                         containing the file.

                      o  ENXIO - Device does not exist.

                      o  EPIPE - Broken pipe.

                      o  ESPIPE - Illegal seek in a file opened for
                         append.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This indicates that an I/O error occurred
                         for which there is no equivalent C error
                         code.
 

3  Example

     The following example shows how to print a date and time in the
     form "Sunday, July 3, 10:02", followed by pi to five decimal
     places:

       #include <math.h>
       #include <stdio.h>
       #include <wchar.h>
       /* . . . */
       wchar_t *weekday, *month; /* pointers to wide-character strings */
       int day, hours, min;
       fwprintf(stdout, L"%ls, %ls %d, %.2d:%.2d\n",
          weekday, month, day, hour, min);
       fwprintf(stdout, L"pi = %.5f\n", 4 * atan(1.0));
 

2  fwrite
   Writes a specified number of items to the file.

   Format

     #include  <stdio.h>

     size_t fwrite  (const void *ptr, size_t size_of_item, size_t  
                    number_items, FILE *file_ptr);
 

3  Arguments
 

ptr

   A pointer to the memory location from which information is being
   written. The type of the object pointed to is determined by the
   type of the item being written.
 

size_of_item

   The size, in bytes, of the items being written.
 

number_items

   The number of items to be written.
 

file_ptr

   A file pointer that indicates the file to which the items are
   being written.
 

3  Description
   The type size_t is defined in the header file <stdio.h> as
   follows:

   typedef unsigned int size_t

   The writing begins at the current location in the file. The items
   are written from storage beginning at the location given by the
   first argument. You must also specify the size of an item, in
   bytes.

   If the file pointed to by file_ptr is a record file, the fwrite
   function outputs at least number_items records, each of length
   size_of_item.
 

3  Return_Value

   x                  The number of items written. The number of
                      records written depends upon the maximum
                      record size of the file.
 

2  fwscanf
   Reads input from the stream under control of the wide-character
   format string.

   Format

     #include  <wchar.h>

     int fwscanf  (FILE *stream, const wchar_t *format, . . . );
 

3  Arguments
 

stream

   A file pointer.
 

format

   A pointer to a wide-character string containing the format
   specification.
 

 . . .

   Optional expressions whose results correspond to conversion
   specifications given in the format specification.

   If no conversion specifications are given, you can omit the input
   pointers. Otherwise, the function calls must have exactly as
   many input pointers as there are conversion specifications, and
   the conversion specifications must match the types of the input
   pointers.

   Conversion specifications are matched to input sources in left-
   to-right order. Excess input pointers, if any, are ignored.
 

3  Description
   The fwscanf function reads input from the stream pointed to by
   stream under the control of the wide-character string pointed
   to by format. If there are insufficient arguments for the
   format, the behavior is undefined. If the format is exhausted
   while arguments remain, the excess arguments are evaluated, but
   otherwise ignored.

   The format is composed of zero or more directives that include:

   o  One or more white-space wide characters.

   o  An ordinary wide character (neither a percent (%))  nor a
      white-space wide character).

   o  Conversion specifications.

   Each conversion specification is introduced by the wide character
   %.

   If the stream pointed to by the stream argument has no
   orientation, fwscanf makes the stream wide-oriented.
 

3  Return_Values

   n                  The number of input items assigned, sometimes
                      fewer than provided for, or even zero, in the
                      event of an early matching failure.
   EOF                Indicates an error; input failure occurs
                      before any conversion.
 

2  gcvt
   Converts its argument to a null-terminated string of ASCII digits
   and returns the address of the string.

   Format

     #include  <stdlib.h>

     char *gcvt  (double value, int ndigit, char *buffer);
 

3  Function_Variants
   The gcvt function has variants named _gcvt32 and _gcvt64 for use
   with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

value

   An object of type double that is converted to a null-terminated
   string of ASCII digits.
 

ndigit

   The number of ASCII digits to use in the converted string. If
   ndigit is less than 6, the value of 6 is used.
 

buffer

   A storage location to hold the converted string.
 

3  Description
   The gcvt function places the converted string in a buffer and
   returns the address of the buffer. If possible, gcvt produces
   ndigit significant digits in F-format, or if not possible, in
   E-format. Trailing zeros are suppressed.

   The ecvt, fcvt, and gcvt functions represent the following
   special values specified in the IEEE Standard for floating-point
   arithmetic:

   Value         Representation

   Quiet NaN     NaNQ
   Signalling    NaNS
   NaN
   +Infinity     Infinity
   -Infinity     -Infinity

   The sign associated with each of these values is stored into the
   sign argument. In IEEE floating-point representation, a value
   of 0 (zero) can be positive or negative, as set by the sign
   argument.

   See also fcvt and ecvt.
 

3  Return_Value

   x                  The address of the buffer.
 

2  getc
   Returns the next character from a specified file.

   Format

     #include  <stdio.h>

     int getc  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A pointer to the file to be accessed.
 

3  Description
   The getc macro returns the next byte from the input stream
   specified by the file_ptr parameter and moves the file pointer,
   if defined, ahead one byte in the input stream.

   Since getc is a macro, a file pointer argument with side effects
   (for example, getc (*f++)) might be evaluated incorrectly.
   In such a case, use the fgetc function instead. See the fgetc
   function.

   See also getc_unlocked.
 

3  Return_Values

   n                  The returned character.
   EOF                Indicates the end-of-file or an error.
 

2  getc_unlocked
   Same as getc, except used only within a scope protected by
   flockfile and funlockfile.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     int getc_unlocked  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The reentrant version of the getc macro is locked against
   multiple threads calling it simultaneously. This incurs overhead
   to ensure integrity of the stream. The unlocked version of this
   call, getc_unlocked can be used to avoid the overhead. The getc_
   unlocked macro is functionally identical to the getc macro,
   except that it is not required to be implemented in a thread-
   safe manner. The getc_unlocked macro can be safely used only
   within a scope that is protected by the flockfile and funlockfile
   functions used as a pair. The caller must ensure that the stream
   is locked before getc_unlocked is used.

   Since getc_unlocked is a macro, a file pointer argument with side
   effects might be evaluated incorrectly. In such a case, use the
   fgetc_unlocked function instead.

   See also flockfile, ftrylockfile, and funlockfile.
 

3  Return_Values

   n                  The returned character.
   EOF                Indicates the end-of-file or an error.
 

2  [w]getch
   Get a character from the terminal screen and echo it on the
   specified window. The getch function echoes the character on
   the stdscr window.

   Format

     #include  <curses.h>

     char getch();

     char wgetch  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Description
   The getch and wgetch functions refresh the specified window
   before fetching a character. For more information, see the
   scrollok function.
 

3  Return_Values

   x                  The returned character.
   ERR                Indicates that the function makes the screen
                      scroll illegally.
 

2  getchar
   Reads a single character from the standard input (stdin).

   Format

     #include  <stdio.h>

     int getchar  (void);
 

3  Description
   The getchar function is identical to fgetc(stdin).

   See also getchar_unlocked.
 

3  Return_Values

   x                  The next character from stdin, converted to
                      int.
   EOF                Indicates the end-of-file or an error.
 

2  getchar_unlocked
   Same as getchar, except used only within a scope protected by
   flockfile and funlockfile.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     int getchar_unlocked  (void);
 

3  Description
   The reentrant version of the getchar function is locked against
   multiple threads calling it simultaneously. This incurs overhead
   to ensure integrity of the input stream. The unlocked version of
   this call, getchar_unlocked can be used to avoid the overhead.
   The getchar_unlocked function is functionally identical to
   the getchar function, except that it is not required to be
   implemented in a thread-safe manner. The getchar_unlocked
   function can be safely used only within a scope that is protected
   by the flockfile and funlockfile functions used as a pair. The
   caller must ensure that the stream is locked before getchar_
   unlocked is used.

   See also flockfile, ftrylockfile, and funlockfile.
 

3  Return_Values

   x                  The next character from stdin, converted to
                      int.
   EOF                Indicates the end-of-file or an error.
 

2  getclock
   Gets the current value of the systemwide clock.

   Format

     #include  <timers.h>

     int getclock  (int clktyp, struct timespec *tp);
 

3  Arguments
 

clktyp

   The type of systemwide clock.
 

tp

   Pointer to a timespec structure space where the current value of
   the systemwide clock is stored.
 

3  Description
   The getclock function sets the current value of the clock
   specified by clktyp into the location pointed to by tp.

   The clktyp argument is given as a symbolic constant name,
   as defined in the <timers.h> header file. Only the TIMEOFDAY
   symbolic constant, which specifies the normal time-of-day clock
   to access for systemwide time, is supported.

   For the clock specified by TIMEOFDAY, the value returned by
   this function is the elapsed time since the Epoch. The Epoch
   is referenced to 00:00:00 UTC (Coordinated Universal Time) 1 Jan
   1970.

   The getclock function returns a timespec structure, which is
   defined in the <timers.h> header file as follows:

    struct  timespec {

     unsigned long  tv_sec   /* Elapsed time in seconds since the Epoch*/
     long           tv_nsec  /* Elapsed time as a fraction of a second */
                             /* since the Epoch (in nanoseconds)       */

    };
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to one of the
                      following values:

                      o  EINVAL - The clktyp argument does not
                         specify a known systemwide clock.

                         Or, the value of SYS$TIMEZONE_DIFFERENTIAL
                         logical is wrong.

                      o  EIO - An error occurred when the systemwide
                         clock specified by the clktyp argument was
                         accessed.
 

2  getcwd
   Returns a pointer to the file specification for the current
   working directory.

   Format

     #include  <unistd.h>

     char *getcwd  (char *buffer, size_t size); (ISO POSIX-1)

     char *getcwd  (char *buffer, unsigned int size, . . . ); 
                     (DEC C Extension)
 

3  Function_Variants
   The getcwd function has variants named _getcwd32 and _getcwd64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

buffer

   Pointer to a character string large enough to hold the directory
   specification.

   If buffer is a NULL pointer, getcwd obtains size bytes of space
   using malloc. In this case, you can use the pointer returned by
   getcwd as the argument in a subsequent call to free.
 

size

   The length of the directory specification to be returned.
 

 . . .

   An optional argument that can be either 1 or 0. If you specify 1,
   the directory specification is returned in OpenVMS format. If you
   specify 0, the directory specification (pathname) is returned in
   UNIX style format. If you omit this argument, getcwd returns the
   filename according to your current command-language interpreter
   (CLI).
 

3  Return_Values

   x                  A pointer to the file specification.
   NULL               Indicates an error.
 

2  getdtablesize
   Gets the total number of file descriptors that a process can have
   open simultaneously.

   Format

     #include  <unistd.h>

     int getdtablesize  (void);
 

3  Description
   The getdtablesize function returns the total number of file
   descriptors that a process can have open simultaneously. Each
   process is limited to a fixed number of open file descriptors.

   The number of file descriptors that a process can have open is
   the minumum of the following:

   o  Compaq C RTL open file limit-65535 on OpenVMS Alpha and
      Integrity servers.

   o  SYSGEN CHANNELCNT parameter-permanent I/O channel count.

   o  Process open file quota FILLM parameter-number of open files
      that can be opened by a process at one time.
 

3  Return_Values

   x                  The number of file descriptors that a process
                      can have open simultaneously.
   -1                 Indicates an error.
 

2  getegid
   With POSIX IDs disabled, this function is equivalent to getgid
   and returns the group number from the user identification code
   (UIC).

   With POSIX IDs enabled, this function returns the effective group
   ID of the calling process.

   Format

     #include  <unistd.h>

     gid_t getegid  (void);
 

3  Description

   The getegid function can be used with POSIX style identifiers
   (IDs) or with UIC-based identifiers.

   POSIX style IDs are supported on OpenVMS Version 7.3-2 and
   higher.

   With POSIX style IDs disabled, the getegid and getgid functions
   are equivalent and return the group number from the current UIC.
   For example, if the UIC is [313,031], 313 is the group number.

   With POSIX style IDs enabled, getegid returns the effective group
   ID of the calling process, and getgid returns the real group ID
   of the calling process. The real group ID is specified at login
   time. The effective group ID is more transient, and determines
   additional access permission during execution of a set-group-ID
   process. It is for such processes that the getgid function is
   most useful.

   The getegid function is always successful; no return value is
   reserved to indicate an error.

   See also geteuid and getuid.
 

3  Return_Value

   x                  The effective group ID (POSIX IDs enabled),
                      or the group number from the UIC (POSIX IDs
                      disabled).
 

2  getenv
   Searches the environment array for the current process and
   returns the value associated with a specified environment name.

   Format

     #include  <stdlib.h>

     char *getenv  (const char *name);
 

3  Argument
 

name

   One of the following values:

   o  HOME-Your login directory

   o  TERM-The type of terminal being used

   o  PATH-The default device and directory

   o  USER-The name of the user who initiated the process

   o  Logical name or command-language interpreter (CLI) symbolic
      name

   o  An environment variable set with setenv or putenv

   The case of the specified name is important.
 

3  Description
   In certain situations, the getenv function attempts to perform a
   logical name translation on the user-specified argument:

   1. If the argument to getenv does not match any of the
      environment strings present in your environment array, getenv
      attempts to translate your argument as a logical name by
      searching the logical name tables indicated by the LNM$FILE_
      DEV logical, as is done for file processing.

      getenv first does a case-sensitive lookup. If that fails, it
      does a case-insensitive lookup. In most instances, logical
      names are defined in uppercase, but getenv can also find
      logical names that include lowercase letters.

      getenv does not perform iterative logical name translation.

   2. If the logical name is a search list with multiple equivalence
      values, the returned value points to the first equivalence
      value. For example:

      $ DEFINE A B,C

      ptr = getenv("A");

      A returns a pointer to "B".

   3. If no logical name exists, getenv attempts to translate the
      argument string as a CLI symbol. If it succeeds, it returns
      the translated symbol text. If it fails, the return value is
      NULL.

      getenv does not perform iterative CLI translation.

   If your CLI is the DEC/Shell, the function does not attempt a
   logical name translation since Shell environment symbols are
   implemented as DCL symbols.

                                 NOTES

      o  In OpenVMS Version 7.1, a cache of OpenVMS environment
         variables (that is, logical names and DCL symbols)
         was added to the getenv function to avoid the library
         making repeated calls to translate a logical name or
         to obtain the value of a DCL symbol. By default, the
         cache is disabled. If your application does not need to
         track changes in OpenVMS environment variables that can
         occur during its execution, the cache can be enabled
         by enabling the DECC$ENABLE_GETENV_CACHE logical before
         invoking the application.

      o  Do not use the setenv, getenv, and putenv functions
         to manipulate symbols and logicals. Instead use the
         OpenVMS library calls lib$set_logical, lib$get_logical,
         lib$set_symbol, and lib$get_symbol. The *env functions
         deliberately provide UNIX behavior, and are not a
         substitute for these OpenVMS runtime library calls.

         OpenVMS DCL symbols, not logical names, are the closest
         analog to environment variables on UNIX systems. While
         getenv is a mechanism to retrieve either a logical name
         or a symbol, it maintains an internal cache of values for
         use with setenv and subsequent getenv calls. The setenv
         function does not write or create DCL symbols or OpenVMS
         logical names.

         This is consistent with UNIX behavior. On UNIX systems,
         setenv does not change or create any symbols that will be
         visible in the shell after the program exits.
 

3  Return_Values

   x                  Pointer to an array containing the translated
                      symbol. An equivalence name is returned at
                      index zero.
   NULL               Indicates that the translation failed.
 

2  geteuid
   With POSIX IDs disabled, this function is equivalent to getuid
   and returns the member number (in OpenVMS terms) from the user
   identification code (UIC).

   With POSIX IDs enabled, this function returns the effective user
   ID.

   Format

     #include  <unistd.h>

     uid_t geteuid  (void);
 

3  Description
   The geteuid function can be used with POSIX style identifiers
   (IDs) or with UIC-based identifiers.

   POSIX style IDs are supported on OpenVMS Version 7.3-2 and
   higher.

   With POSIX style IDs disabled (the default), the geteuid and
   getuid functions are equivalent and return the member number from
   the current UIC as follows:

   o  For programs compiled with the _VMS_V6_SOURCE feature-
      test macro or programs that do not include the <unistd.h>
      header file, the getuid and geteuid functions return the
      member number of the OpenVMS UIC. For example, if the UIC
      is [313,31], then the member number, 31, is returned.

   o  For programs compiled without the _VMS_V6_SOURCE feature-
      test macro that do include the <unistd.h> header file, the
      full UIC is returned in decimal after converting the octal
      representation to decimal. For example, if the UIC is [313,
      31] then 13303833 is returned. (13303833 = 25 + 203 * 65536;
      Octal 31 = 25 decimal; Octal 313 = 203 decimal.)

   With POSIX style IDs enabled, geteuid returns the effective user
   ID of the calling process, and getuid returns the real user ID of
   the calling process.

   See also getegid and getgid.
 

3  Return_Value

   x                  The effective user ID (POSIX IDs enabled), or
                      the member number from the current UIC or the
                      full UIC (POSIX IDs disabled).
 

2  getgid
   With POSIX IDs disabled, this function is equivalent to getegid
   and returns the group number from the user identification code
   (UIC).

   With POSIX IDs enabled, this function returns the real group ID.

   Format

     #include  <unistd.h>

     gid_t getgid  (void);
 

3  Description
   The getgid function can be used with POSIX style identifiers or
   with UIC-based identifiers.

   POSIX style IDs are supported on OpenVMS Version 7.3-2 and
   higher.

   With POSIX style IDs disabled (the default), the getegid and
   getgid functions are equivalent and return the group number from
   the current UIC. For example, if the UIC is [313,031], 313 is the
   group number.

   With POSIX style IDs enabled, getegid returns the effective group
   ID of the calling process, and getgid returns the real group ID
   of the calling process. The real group ID is specified at login
   time. The effective group ID is more transient, and determines
   additional access permission during execution of a set-group-ID
   process. It is for such processes that the getgid function is
   most useful.

   See also geteuid and getuid.
 

3  Return_Value

   x                  The real group ID (POSIX IDs enabled), or the
                      group number from the current UIC (POSIX IDs
                      disabled).

   Gets a group database entry.
 

2  getgrent
   Gets a group database entry.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <grp.h>

     struct group *getgrent  (void);
 

3  Description
   The getgrent function returns the next group in the sequential
   search, returning a pointer to a structure containing the broken-
   out fields of an entry in the group database.

   When first called, getgrent returns a pointer to a group
   structure containing the first entry in the group database.
   Thereafter, it returns a pointer to the next group structure
   in the group database, so successive calls can be used to search
   the entire database.

   If an end-of-file or an error is encountered on reading, getgrent
   returns a NULL pointer and sets errno.
 

3  Return_Values

   x                  Pointer to a group structure, if successful.
   NULL               Indicates that an error occurred. The function
                      sets errno to one of the following values:

                      o  EACCES - The user process does not have
                         appropriate privileges enabled to access
                         the user authorization file.

                      o  EINTR - A signal was intercepted during the
                         operation.

                      o  EIO - Indicates that an I/O error occurred.

                      o  EMFILE - OPEN_MAX file descriptors are
                         currently open in the calling process.

                      o  ENFILE - The maximum allowable number of
                         files is currently open in the system.
 

2  getgrgid
   Gets a group database entry for a group ID.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <types.h>

     #include  <grp.h>

     struct group *getgrgid  (gid_t gid);
 

3  Argument
 

gid

   The group ID of the group for which the group database entry is
   to be retrieved.
 

3  Description
   The getgrgid function searches the group database for an entry
   with a matching gid and returns a pointer to the group structure
   containing the matching entry.
 

3  Return_Values

   x                  Pointer to a valid group structure containing
                      a matching entry.
   NULL               An error occurred.

                      Note: The return value points to a static area
                      that is overwritten by subsequent calls to
                      getgrent, getgrgid, or getgrnam.

                      On error, the function sets errno to one of
                      the following values:

                      o  EACCES - The user process does not have
                         appropriate privileges enabled to access
                         the user authorization file.

                      o  EIO - An I/O error has occurred.

                      o  EINTR - A signal was intercepted during
                         getgrgid.

                      o  EMFILE - OPEN_MAX file descriptors are
                         currently open in the calling process.

                      o  ENFILE - The maximum allowable number of
                         files is currently open in the system.

                      Applications checking for error situations
                      must set errno to 0 before calling getgrgid.
                      If errno is set on return, an error has
                      occurred.
 

2  getgrgid_r
   Gets a group database entry for a group ID.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <types.h>

     #include  <grp.h>

     int getgrgid_r  (gid_t gid, struct group *grp, char *buffer,  
                     size_t bufsize, struct group **result);
 

3  Arguments
 

gid

   The group ID of the group for which the group database entry is
   to be retrieved.
 

grp

   Storage area to hold the retrieved group structure.
 

buffer

   The working buffer that is able to hold the longest group entry
   in the database.
 

bufsize

   The length, in characters, of buffer.
 

result

   Upon successful return, result points to the retrieved group
   structure.

   Upon unsuccessful return, result is set to NULL.
 

3  Description
   The getgrgid_r function updates the group structure pointed to
   by grp and stores a pointer to that structure at the location
   pointed to by result. The structure contains an entry from the
   group database with a matching gid. Storage referenced by the
   group structure is allocated from the memory provided with the
   buffer argument, which is bufsize characters in size. The maximum
   size needed for this buffer can be determined with the _SC_GETGR_
   R_SIZE_MAX parameter of the sysconf function. On error or if the
   requested entry is not found, a NULL pointer is returned at the
   location pointed to by result.
 

3  Return_Values

   0                  Successful completion.
   x                  On error, the function sets the return value
                      to one of the following:

                      o  EACCES - The user process does not have
                         appropriate privileges enabled to access
                         the user authorization file.

                      o  EIO - An I/O error has occurred.

                      o  EINTR - A signal was intercepted during
                         getgrgid.

                      o  EMFILE - OPEN_MAX file descriptors are
                         currently open in the calling process.

                      o  ENFILE - The maximum allowable number of
                         files is currently open in the system.

                      o  ERANGE - Insufficient storage was supplied
                         through the buffer and bufsize arguments
                         to contain the data to be referenced by the
                         resulting group structure.
 

2  getgrnam
   Gets a group database entry for a name.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <types.h>

     #include  <grp.h>

     struct group *getgrnam  (const char *name);
 

3  Argument
 

name

   The group name of the group for which the group database entry is
   to be retrieved.
 

3  Description
   The getgrnam function searches the group database for an
   entry with a matching name, and returns a pointer to the group
   structure containing the matching entry.
 

3  Return_Values

   x                  Pointer to a valid group structure containing
                      a matching entry.
   NULL               Indicates an error.

                      Note: The return value points to a static area
                      which is overwritten by subsequent calls to
                      getgrent, getgrgid, or getgrnam.

                      On error, the function sets the return value
                      to one of the following:

                      o  EACCES - The user process does not have
                         appropriate privileges enabled to access
                         the user authorization file.

                      o  EIO - An I/O error has occurred.

                      o  EINTR - A signal was intercepted during
                         getgrnam.

                      o  EMFILE - OPEN_MAX file descriptors are
                         currently open in the calling process.

                      o  ENFILE - The maximum allowable number of
                         files is currently open in the system.

                      Applications wishing to check for error
                      situations should set errno to 0 before
                      calling getgrnam. If errno is set on return,
                      an error occurred.
 

2  getgrnam_r
   Gets a group database entry for a name.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <types.h>

     #include  <grp.h>

     int getgrnam_r  (const char *name, struct group *grp,         
                     char *buffer, size_t bufsize, struct group     
                     **result);
 

3  Arguments
 

name

   The group name of the group for which the group database entry is
   to be retrieved.
 

grp

   Storage area to hold the retrieved group structure.
 

buffer

   The working buffer that is able to hold the longest group entry
   in the database.
 

bufsize

   The length, in characters, of buffer.
 

result

   Upon successful return, result points to the retrieved group
   structure.

   Upon unsuccessful return, result is set to NULL.
 

3  Description
   The getgrnam_r function updates the group structure pointed to
   by grp and stores a pointer to that structure at the location
   pointed to by result. The structure contains an entry from the
   group database with a matching name. Storage referenced by the
   group structure is allocated from the memory provided with the
   buffer argument, which is bufsize characters in size. The maximum
   size needed for this buffer can be determined with the _SC_GETGR_
   R_SIZE_MAX parameter of the sysconf function. On error or if the
   requested entry is not found, a NULL pointer is returned at the
   location pointed to by result.
 

3  Return_Values

   0                  Successful completion.
   x                  On error, the function sets the return value
                      to one of the following:

                      o  EACCES - The user process does not have
                         appropriate privileges enabled to access
                         the user authorization file.

                      o  EIO - An I/O error has occurred.

                      o  EINTR - A signal was intercepted during
                         getgrnam.

                      o  EMFILE - OPEN_MAX file descriptors are
                         currently open in the calling process.

                      o  ENFILE - The maximum allowable number of
                         files is currently open in the system.

                      o  ERANGE - Insufficient storage was supplied
                         through the buffer and bufsize arguments
                         to contain the data to be referenced by the
                         resulting group structure.
 

2  getgroups
   Gets the current supplementary group IDs of the calling process.

   Format

     #include  <unistd.h>

     int getgroups  (int gidsetsize, gid_t grouplist[]);
 

3  Arguments
 

gidsetsize

   Indicates the number of entries that can be stored in the array
   pointed to by the grouplist parameter.
 

grouplist

   Points to the array in which the supplementary group IDs of
   the process are stored. The effective group ID of the process
   is not returned by the getgroups function if it is not also a
   supplementary group ID of the calling process.
 

3  Description
   The getgroups function gets the current supplementary group IDs
   of the calling process. The list is stored in the array pointed
   to by the grouplist parameter. The gidsetsize parameter indicates
   the number of entries that can be stored in this array.

   The getgroups function never returns more IDs than the value
   indicated by the sysconf parameter _SC_NGROUPS_MAX.

   See also getgid and setsid.
 

3  Return_Value

   n                  The number of elements stored in the array
                      pointed to by the grouplist parameter.
   -1                 Indicates failure. errno might be set to one
                      of the following values:

                      o  EFAULT - The gidsetsize and grouplist
                         parameters specify an array that is
                         partially or completely outside of the
                         allocated address space of the process.

                      o  EINVAL - The gidsetsize parameter is
                         nonzero and smaller than the number of
                         supplementary group IDs.
 

2  getitimer
   Returns the value of interval timers.

   Format

     #include  <time.h>

     int getitimer  (int which, struct itimerval *value);
 

3  Arguments
 

which

   The type of interval timer. The Compaq C RTL supports only
   ITIMER_REAL.
 

value

   Pointer to an itimerval structure whose members specify a timer
   interval and the time left to the end of the interval.
 

3  Description
   The getitimer function returns the current value for the timer
   specified by the which argument in the structure pointed to by
   value.

   A timer value is defined by the itimerval structure:

          struct itimerval {
                  struct  timeval it_interval;
                  struct  timeval it_value;
          };

   The following table lists the values for the itimerval structure
   members:

   itimerval Member
   Value              Meaning

   it_interval = 0    Disables a timer after its next expiration and
                      assumes it_value is nonzero.
   it_interval =      Specifies a value used in reloading it_value
   nonzero            when the timer expires.
   it_value = 0       Disables a timer.
   it_value =         Indicates the time to the next timer
   nonzero            expiration.

   Time values smaller than the resolution of the system clock are
   rounded up to this resolution.

   The Compaq C RTL provides each process with one interval timer,
   defined in the <time.h> header file as ITIMER_REAL. This timer
   decrements in real time and delivers a SIGALRM signal when the
   timer expires.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to EINVAL
                      (The value argument specified a time that was
                      too large to handle.)
 

2  getlogin
   Gets the login name.

   Format

     #include  <unistd.h>

     char *getlogin  (void);

     int *getlogin_r  (char *name, size_t namesize);
 

3  Description
   The getlogin function returns the login name of the user
   associated with the current session. If getlogin returns a non-
   null pointer, then that pointer points to the name that the user
   logged in under, even if there are several login names with the
   same user ID.

   The getlogin_r function is the reentrant version of getlogin.
   Upon successful completion, getlogin_r returns 0 and puts the
   name associated by the login activity with the controlling
   terminal of the current process in the character array pointed
   to by name. The array is namesize characters long and should
   have space for the name and the terminating null character. The
   maximum size of the login name is LOGIN_NAME_MAX.

   If getlogin_r is successful, name points to the name the user
   used at login, even if there are several login names with the
   same user ID.
 

3  Return_Values

   x                  Upon successful completion, getlogin returns
                      a pointer to a null-terminated string in a
                      static buffer.
   0                  Indicates successful completion of getlogin_r.
   NULL               Indicates an error; errno is set.
 

2  getname
   Returns the file specification associated with a file descriptor.

   Format

     #include  <unixio.h>

     char *getname  (int file_desc, char *buffer, . . . );
 

3  Function_Variants
   The getname function has variants named _getname32 and _getname64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

file_desc

   A file descriptor.
 

buffer

   A pointer to a character string that is large enough to hold the
   file specification.
 

 . . .

   An optional argument that can be either 1 or 0. If you specify
   1, the getname function returns the file specification in OpenVMS
   format. If you specify 0, the getname function returns the file
   specification in UNIX style format. If you omit this argument,
   the getname function returns the filename according to your
   current command-language interpreter (CLI).
 

3  Description
   The getname function places the file specification into the
   area pointed to by buffer and returns that address. The area
   pointed to by buffer should be an array large enough to contain
   a fully qualified file specification (the maximum length is 256
   characters).
 

3  Return_Values

   x                  The address passed in the buffer argument.
   0                  Indicates an error.
 

2  getopt
   A command-line parser that can be used by applications that
   follow UNIX command-line conventions.

   Format

     #include  <unistd.h> (X/Open, POSIX-1)

     #include  <stdio.h> (X/Open, POSIX-2)

     int getopt  (int argc, char * const argv[], const char *optstring);

     extern  char *optarg;

     extern  int optind, opterr, optopt;
 

3  Arguments
 

argc

   The argument count as passed to main.
 

argv

   The argument array as passed to main.
 

optstring

   A string of recognized option characters. If a character is
   followed by a colon, the option takes an argument.
 

3  Description
   The variable optind is the index of the next element of the
   argv vector to be processed. It is initialized to 1 by the
   system, and it is updated by getopt when it finishes with each
   element of argv. When an element of argv contains multiple option
   characters, it is unspecified how getopt determines which options
   have already been processed.

   The getopt function returns the next option character (if one is
   found) from argv that matches a character in optstring, if there
   is one that matches. If the option takes an argument, getopt sets
   the variable optarg to point to the option-argument as follows:

   o  If the option was the last character in the string pointed to
      by an element of argv, then optarg contains the next element
      of argv, and optind is incremented by 2. If the resulting
      value of optind is not less than argc, getopt returns an
      error, indicating a missing option-argument.

   o  Otherwise, optarg points to the string following the option
      character in that element of argv, and optind is incremented
      by 1.

   If one of the following is true, getopt returns -1 without
   changing optind:

      argv[optind] is a NULL pointer
      *argv[optind] is not the character -
      argv[optind] points to the string "-"

   If argv[optind] points to the string "- -" getopt returns -1
   after incrementing optind.

   If getopt encounters an option character not contained in
   optstring, the question-mark character (?)  is returned.

   If getopt detects a missing argument, the colon character (:)
   is returned if the first character of optstring is a colon;
   otherwise, a question-mark character is returned.

   In either of the previous two cases, getopt sets the variable
   optopt to the option character that caused the error. If the
   application has not set the variable opterr to 0 and the first
   character of optstring is not a colon, getopt also prints a
   diagnostic message to stderr.
 

3  Return_Values

   x                  The next option character specified on the
                      command line.

                      A colon is returned if getopt detects a
                      missing argument and the first character of
                      optstring is a colon.

                      A question mark is returned if getopt
                      encounters an option character not in
                      optstring or detects a missing argument and
                      the first character of optstring is not a
                      colon.
   -1                 When all command-line options are parsed.
 

3  Example

     The following example shows how you might process the arguments
     for a utility that can take the mutually exclusive options a
     and b and the options f and o, both of which require arguments:

#include <unistd.h>

int main (int argc, char *argv[ ])
{
         int c;
         int bflg, aflg, errflg;
         char *ifile;
         char *ofile;
         extern char *optarg;
         extern int optind, optopt;
         .
         .
         .
         while ((c = getopt(argc, argv, ":abf:o:)) != -1) {

                switch (c) {
                case 'a':
                        if (bflg)
                                errflg++;
                        else
                                aflg++;
                        break;
                case 'b':
                        if (aflg)
                               errflg++;
                        else {
                               bflg++;
                               bproc();
                        }

                        break;
                case 'f':
                        ifile = optarg;
                        break;
                case 'o':
                        ofile = optarg;
                        break;
                case ':':      /* -f or -o without operand */
                        fprintf (stderr,
                         "Option -%c requires an operand\n"' optopt);
                        errflg++;
                        break;
                case '?':
                        fprintf (stderr,
                                "Unrecognized option -%c\n"' optopt);
                        errflg++;
                }
         }
         if (errflg) {
                fprintf (stderr, "usage: ...");
                exit(2);
         }
         for ( ; optind < argc; optind++)  {
                if (access(argv[optind], R_OK)) {
         .
         .
         .
}

     This sample code accepts any of the following as equivalent:

       cmd -ao arg path path
       cmd -a -o arg path path
       cmd -o arg -a path path
       cmd -a -o arg -- path path
       cmd -a -oarg path path
       cmd -aoarg path path
 

2  getpagesize
   Gets the system page size.

   Format

     #include  <unistd.h>

     int getpagesize  (void);
 

3  Description
   The getpagesize function returns the number of bytes in a page.
   The system page size is useful for specifying arguments to memory
   management system calls.

   The page size is a system page size and is not necessarily the
   same as the underlying hardware page size.
 

3  Return_Value

   x                  Always indicates success. Returns the number
                      of bytes in a page.
 

2  getpgid
   Gets the process group ID for a process.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     pid_t getpgid  (pid_t pid);
 

3  Argument
 

pid

   The process ID for which the group ID is being requested.
 

3  Description
   The getpgid function returns the process group ID of the process
   specified by pid. If pid is 0, the getpgid function returns the
   process group ID of the calling process.

   This function requires that long (32-bit) UID/GID support be
   enabled. See 32-Bit UID and GID Macro (Integrity servers, Alpha)
   for more information.
 

3  Return_Values

   x                  The process group ID of the session leader of
                      the specified process.
   (pid_t)-1          Indicates an error. The function sets errno to
                      one of the following values:

                      o  EPERM - The process specified by pid is
                         not in the same session as the calling
                         process, and the implementation does not
                         allow access to the process group ID of
                         that process from the calling process.

                      o  ESRCH - There is no process with a process
                         ID of pid.

                      o  EINVAL - The value of pid is invalid.
 

2  getpgrp
   Gets the process group ID of the calling process.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     pid_t getpgrp  (void);
 

3  Description
   The getpgrp function returns the process group ID of the calling
   process.

   The getpgrp function is always successful, and no return value is
   reserved to indicate an error.

   This function requires that long (32-bit) UID/GID support be
   enabled. See 32-Bit UID and GID Macro (Integrity servers, Alpha)
   for more information.
 

3  Return_Values

   x                  The process group ID of the calling process.
 

2  getpid
   Returns the process ID of the current process.

   Format

     #include  <unistd.h>

     pid_t getpid  (void);
 

3  Return_Value

   x                  The process ID of the current process.
 

2  getppid
   Returns the parent process ID of the calling process.

   Format

     #include  <unistd.h>

     pid_t getppid  (void);
 

3  Return_Values

   x                  The parent process ID.
   0                  Indicates that the calling process does not
                      have a parent process.
 

2  getpwent
   Accesses user entry information in the user database, returning a
   pointer to a passwd structure.

   Format

     #include  <pwd.h>

     struct passwd *getpwent  (void);
 

3  Function_Variants
   The getpwent function has variants named __32_getpwent and
   __64_getpwent for use with 32-bit and 64-bit pointer sizes,
   respectively.
 

3  Description
   The getpwent function returns a pointer to a structure containing
   fields whose values are derived from an entry in the user
   database. Entries in the database are accessed sequentially by
   getpwent. When first called, getpwent returns a pointer to a
   passwd structure containing the first entry in the user database.
   Thereafter, it returns a pointer to a passwd structure containing
   the next entry in the user database. Successive calls can be used
   to search the entire user database.

   The passwd structure is defined in the <pwd.h> header file as
   follows:

   pw_name    The name of the user.
   pw_uid     The ID of the user.
   pw_gid     The group ID of the principle group of the user.
   pw_dir     The home directory of the user.
   pw_shell   The initial program for the user.

   If an end-of-file or an error is encountered on reading, getpwent
   returns a NULL pointer.

   Because getpwent accesses the user authorization file (SYSUAF)
   directly, the process must have appropriate privileges enabled or
   the function will fail.

                                 NOTES

      All information generated by the getpwent function is stored
      in a per-thread static area and is overwritten on subsequent
      calls to the function.

      Password file entries that are too long are ignored.
 

3  Return_Values

   x                  Pointer to a passwd structure, if successful.
   NULL               Indicates an end-of-file or error occurred.
                      The function sets errno to one of the
                      following values:

                      o  EIO - Indicates that an I/O error occurred
                         or the user does not have appropriate
                         privileges enabled to access the user
                         authorization file (SYSUAF).

                      o  EMFILE - OPEN_MAX file descriptors are
                         currently open in the calling process.

                      o  ENFILE - The maximum allowable number of
                         files is currently open in the system.
 

2  getpwnam
   The getpwnam function returns information about a user database
   entry for the specified name.

   The getpwnam_r function is a reentrant version of getpwnam.

   Format

     #include  <pwd.h>

     struct passwd *getpwnam  (const char *name); (ISO POSIX-1)

     struct passwd *getpwnam  (const char *name, . . . ); 
                              (DEC C Extension)

     int getpwnam_r  (const char *name, struct passwd *pwd,
                     char *buffer, size_t bufsize, struct  
                     passwd **result); (ISO POSIX-1),             
                     (Integrity servers, Alpha)

     int getpwnam_r  (const char *name, struct passwd *pwd,
                     char *buffer, size_t bufsize, struct  
                     passwd **result, . . . ); (DEC C Extension), 
                     (Integrity servers, Alpha)
 

3  Function_Variants
   The getpwnam and getpwnam_r functions have variants named __32_
   getpwnam, _getpwnam_r32 and __64_getpwnam, _getpwnam_r64 for use
   with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

name

   The name of the user for which the attributes are to be read.
 

pwd

   The address of a passwd structure into which the function writes
   its results.
 

buffer

   A working buffer for the result argument that is able to hold the
   largest entry in the passwd structure. Storage referenced by the
   passwd structure is allocated from the memory provided with the
   buffer argument, which is bufsize characters in length.
 

bufsize

   The length of the character array that buffer points to.
 

result

   Upon successful return, is set to pwd. Upon unsuccessful return,
   the result is set to NULL.
 

 . . .

   An optional argument that can be either 1 or 0. If you specify
   1, the directory specification is returned in OpenVMS format. If
   you specify 0, the directory specification (pathname) is returned
   in UNIX style format. If you omit this argument, the function
   returns the directory specification according to your current
   command-language interpreter.
 

3  Description
   The getpwnam function searches the user database for an entry
   with the specified name. The function returns the first user
   entry in the database with the pw_name member of the passwd
   structure that matches the name argument.

   The passwd structure is defined in the <pwd.h> header file as
   follows:

   pw_name    The user's login name.
   pw_uid     The numerical user ID.
   pw_gid     The numerical group ID.
   pw_dir     The home directory of the user.
   pw_shell   The initial program for the user.

                                  NOTE

      All information generated by the getpwnam function is stored
      in a per-thread static area and is overwritten on subsequent
      calls to the function.

   The getpwnam_r function is the reentrant version of getpwnam.
   The getpwnam_r function updates the passwd structure pointed to
   by pwd and stores a pointer to that structure at the location
   pointed to by result. The structure will contain an entry from
   the user database that matches the specified name. Storage
   referenced by the structure is allocated from the memory provided
   with the buffer argument, which is bufsize characters in length.
   The maximum size needed for this buffer can be determined with
   the _SC_GETPW_R_SIZE_MAX parameter of the sysconf function. On
   error or if the requested entry is not found, a NULL pointer is
   returned at the location pointed to by result.

   Applications wishing to check for error situations should set
   errno to 0 before calling getpwnam. If getpwnam returns a NULL
   pointer and errno is nonzero, an error occurred.
 

3  Return_Values

   x                  getpwnam returns a pointer to a valid passwd
                      structure, if a matching entry is found.
   NULL               getpwnam returns NULL if an error occurred
                      or a the specified entry was not found. errno
                      is set to indicate the error. The getpwnam
                      function may fail if:

                      o  EIO - An I/O error has occurred.

                      o  EINTR - A signal was intercepted during
                         getpwnam.

                      o  EMFILE - OPEN_MAX file descriptors are
                         currently open in the calling process.

                      o  ENFILE - The maximum allowable number of
                         files is currently open in the system.

   0                  When successful, getpwnam_r returns 0 and
                      stores a pointer to the updated passwd
                      structure at the location pointed to by
                      result.
   0                  When unsuccessful (on error or if the
                      requested entry is not found), getpwnam_r
                      returns 0 and stores a NULL pointer at the
                      location pointed to by result. The getpwnam_r
                      function may fail if:

                      o  ERANGE - Insufficient storage was supplied
                         through buffer and bufsize to contain the
                         data to be referenced by the resulting
                         passwd structure.
 

3  Example

     When building a sample program with /def=_USE_STD_STAT, you can
     observe the following:

     o  When the DECC$POSIX_STYLE_UID logical is enabled:

        -  For a system, that supports POSIX style identifiers:

           - getpwnam_r API reads information from the TCP/IP proxy
           database and fills UID and GID with values from the
           TCP/IP proxy database.

           - getgrgid_r API returns gr_name and gr_mem from
           the right's database associated with GID returned by
           getpwnam_r API.

        -  System with no support for POSIX style identifiers,
           getpwnam_r fills GID and UID with SYSGEN parameters as
           "DEFUID" and "DEFGID".

     o  When the DECC$POSIX_STYLE_UID logical is not defined:

        getpwnam function returns information about a user database
        entry for the specified name, which is specified in
        SYSUAF.DAT

       #include <unistd>  // getuid()
       #include <pwd>     // getpwuid_r()
       #include <grp>
       #include <errno.h>
       #include <stdio.h>
       #include <string.h>

       main()
       {

       struct passwd pwd2;
       const unsigned int PWD_BUFF_SIZE = 1024; 
       const unsigned int GRP_BUFF_SIZE = 1024;

       struct passwd *p_passwd;
       struct passwd *result;
       struct group *grpresult;
       struct group grp;
       char pwdBuffer[PWD_BUFF_SIZE],*name;
       char grpBuffer[GRP_BUFF_SIZE];
       char buf[PWD_BUFF_SIZE];

       gid_t gid;
       uid_t uid;

       int status;
       p_passwd = getpwnam("user1");
       uid=p_passwd->pw_uid;
       gid=p_passwd->pw_gid;

       printf("User id is %u\n", uid);
       printf("Group id is %u\n", gid);

       status = getpwnam_r("user1", &pwd2, pwdBuffer, PWD_BUFF_SIZE, &result);

       gid = pwd2.pw_gid;

       status = getgrgid_r(gid, &grp, grpBuffer, GRP_BUFF_SIZE, &grpresult);

       gid=grp.gr_gid; name=grp.gr_name;

       strcpy(name,grp.gr_name);

       printf("Group id is %u\n", gid);
       printf("Group name is %s\n", name);

       }

     Running the example program with /def=_USE_STD_STAT produces
     the following result:

     o  When the DECC$POSIX_STYLE_UID logical is NOT enabled, prints
        uid as 11010118 (result of 65536*168+ 70) and gid as 168
        with group name as RTL.

     o  When the DECC$POSIX_STYLE_UID logical is enabled and POSIX
        style identifiers are supported, prints uid as 70, gid as
        168 with group name as FOR_POSIX_TEST (retrieved from TCP/IP
        proxy database).

     o  When the DECC$POSIX_STYLE_UID logical is enabled, but POSIX
        style identifiers are not supported, prints uid as DEFUID,
        gid as DEFGID with group name as invalid buffer.
 

2  getpwuid
   The getpwuid function returns information about a user database
   entry for the specified uid.

   The getpwuid_r function is a reentrant version of getpwuid.

   These functions are OpenVMS Alpha only.

   Format

     #include  <pwd.h>

     struct passwd *getpwuid  (uid_t uid); (ISO POSIX-1)

     struct passwd *getpwuid  (uid_t uid, . . . ); (DEC C Extension)

     int getpwuid_r  (uid_t uid, struct passwd *pwd, char *buffer, 
                     size_t bufsize, struct passwd **result); 
                    (ISO POSIX-1)

     int getpwuid_r  (uid_t uid, struct passwd *pwd, char *buffer,
                     size_t bufsize, struct passwd **result, . . . );
                     (DEC C Extension)
 

3  Function_Variants
   The getpwuid and getpwuid_r functions have variants named __32_
   getpwuid, _getpwuid_r32 and __64_getpwuid, _getpwuid_r64 for use
   with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

uid

   The user ID (UID) for which the attributes are to be read.
 

pwd

   The location where the retrieved passwd structure is to be
   placed.
 

buffer

   A working buffer for the result argument that is able to hold the
   entry in the passwd structure. Storage referenced by the passwd
   structure is allocated from the memory provided with the buffer
   argument, which is bufsize characters in size.
 

bufsize

   The length of the character array that buffer points to.
 

result

   Upon successful return, result is set to pwd. Upon unsuccessful
   return, result is set to NULL.
 

 . . .

   An optional argument that can be either 1 or 0. If you specify
   1, the directory specification is returned in OpenVMS format. If
   you specify 0, the directory specification (pathname) is returned
   in UNIX style format. If you omit this argument, the function
   returns the directory specification according to your current
   command-language interpreter.
 

3  Description
   The getpwuid function searches the user database for an entry
   with the specified uid. The function returns the first user entry
   in the database with a pw_uid member of the passwd structure that
   matches the uid argument.

   The passwd structure is defined in the <pwd.h> header file as
   follows:

   pw_name    The user's login name.
   pw_uid     The numerical user ID.
   pw_gid     The numerical group ID.
   pw_dir     The home directory of the user.
   pw_shell   The initial program for the user.

                                  NOTE

      All information generated by the getpwuid function is stored
      in a per-thread static area and is overwritten on subsequent
      calls to the function.

   The getpwuid_r function is the reentrant version of getpwuid.
   The getpwuid_r function updates the passwd structure pointed to
   by pwd and stores a pointer to that structure at the location
   pointed to by result. The structure will contain an entry from
   the user database with a matching uid. Storage referenced by the
   structure is allocated from the memory provided with the buffer
   argument, which is bufsize characters in size. The maximum size
   needed for this buffer can be determined with the _SC_GETPW_R_
   SIZE_MAX parameter of the sysconf function. On error or if the
   requested entry is not found, a NULL pointer is returned at the
   location pointed to by result.

   Applications wishing to check for error situations should set
   errno to 0 before calling getpwuid. If getpwuid returns a NULL
   pointer and errno is nonzero, an error occurred.

   See also getuid to know how UIC is represented.
 

3  Return_Values

   x                  getpwuid returns a pointer to a valid passwd
                      structure, if a matching entry is found.
   NULL               getpwuid returns NULL if an error occurred or
                      a matching entry was not found. errno is set
                      to indicate the error. The getpwuid function
                      may fail if:

                      o  EIO - An I/O error has occurred.

                      o  EINTR - A signal was intercepted during
                         getpwnam.

                      o  EMFILE - OPEN_MAX file descriptors are
                         currently open in the calling process.

                      o  ENFILE - The maximum allowable number of
                         files is currently open in the system.

   0                  When successful, getpwuid_r returns 0 and
                      stores a pointer to the updated passwd
                      structure at the location pointed to by
                      result.
   0                  When unsuccessful (on error or if the
                      requested entry is not found), getpwuid_r
                      returns 0 and stores a NULL pointer at the
                      location pointed to by result. The getpwuid_r
                      function may fail if:

                      o  ERANGE - Insufficient storage was supplied
                         through buffer and bufsize to contain the
                         data to be referenced by the resulting
                         passwd structure.
 

2  gets
   Reads a line from the standard input (stdin).

   Format

     #include  <stdio.h>

     char *gets  (char *str);
 

3  Function_Variants
   The gets function has variants named _gets32 and _gets64 for use
   with 32-bit and 64-bit pointer sizes, respectively.
 

3  Argument
 

str

   A pointer to a character string that is large enough to hold the
   information fetched from stdin.
 

3  Description
   The new-line character (\n)  that ends the line is replaced by
   the function with an ASCII null character (\0).

   When stdin is opened in record mode, gets treats the end of a
   record the same as a new-line character and, therefore, reads
   up to and including a new-line character or to the end of the
   record.
 

3  Return_Values

   x                  A pointer to the str argument.
   NULL               Indicates that an error has occurred or that
                      the end-of-file was encountered before a new-
                      line character was encountered. The contents
                      of str are undefined if a read error occurs.
 

2  getsid
   Gets the process group ID of the session leader.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     pid_t getsid  (pid_t pid);
 

3  Argument
 

pid

   The process ID of the process whose session leader process group
   ID is being requested.
 

3  Description
   The getsid function obtains the process group ID of the process
   that is the session leader of the process specified by pid. If
   pid is (pid_t)0, it specifies the calling process.

   This function requires that long (32-bit) UID/GID support be
   enabled. See 32-Bit UID and GID Macro (Integrity servers, Alpha)
   for more information.
 

3  Return_Values

   x                  The process group ID of the session leader of
                      the specified process.
   (pid_t)-1          Indicates an error. The function sets errno to
                      one of the following values:

                      o  EPERM - The process specified by pid is
                         not in the same session as the calling
                         process, and the implementation does not
                         allow access to the process group ID of
                         the session leader of that process from the
                         calling process.

                      o  ESRCH - There is no process with a process
                         ID of pid.
 

2  [w]getstr
   Get a string from the terminal screen, store it in the variable
   str, and echo it on the specified window. The getstr function
   works on the stdscr window.

   Format

     #include  <curses.h>

     int getstr  (char *str);

     int wgetstr  (WINDOW *win, char *str);
 

3  Arguments
 

win

   A pointer to the window.
 

str

   Must be large enough to hold the character string fetched from
   the window.
 

3  Description
   The getstr and wgetstr functions refresh the specified window
   before fetching a string. The new-line terminator is stripped
   from the fetched string. For more information, see the scrollok
   function.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function makes the screen
                      scroll illegally.
 

2  gettimeofday
   Gets the date and time.

   Format

     #include  <time.h>

     int gettimeofday  (struct timeval *tp, void *tzp);
 

3  Arguments
 

tp

   Pointer to a timeval structure, defined in the <time.h> header
   file.
 

tzp

   A NULL pointer. If this argument is not a NULL pointer, it is
   ignored.
 

3  Description
   The gettimeofday function gets the current time (expressed as
   seconds and microseconds) since 00::00 Coordinated Universal
   Time, January 1, 1970. The current time is stored in the timeval
   structure pointed to by the tp argument.

   The tzp argument is intended to hold time-zone information set
   by the kernel. However, because the OpenVMS kernel does not
   set time-zone information, the tzp argument should be NULL. If
   it is not NULL, it is ignored. This function is supported for
   compatibility with BSD programs.

   If the value of the SYS$TIMEZONE_DIFFERENTIAL logical is wrong,
   the function fails with errno set to EINVAL.
 

3  Return_Values

   0                  Indicates success.
   -1                 An error occurred. errno is set to indicate
                      the error.
 

2  getuid
   With POSIX IDs disabled, this function is equivalent to geteuid
   and returns the member number (in OpenVMS terms) from the user
   identification code (UIC).

   With POSIX IDs enabled, returns the real user ID.

   Format

     #include  <unistd.h>

     uid_t getuid  (void);
 

3  Description
   The getuid function can be used with POSIX style identifiers or
   with UIC-based identifiers.

   POSIX style IDs are supported on OpenVMS Version 7.3-2 and
   higher.

   With POSIX style IDs disabled (the default), the geteuid and
   getuid functions are equivalent and return the member number from
   the current UIC as follows:

   o  For programs compiled with the _VMS_V6_SOURCE feature-
      test macro or programs that do not include the <unistd.h>
      header file, the getuid and geteuid functions return the
      member number of the OpenVMS UIC. For example, if the UIC
      is [313,31], then the member number, 31, is returned.

   o  For programs compiled without the _VMS_V6_SOURCE feature-
      test macro that do include the <unistd.h> header file, the
      full UIC is returned in decimal after converting the octal
      representation to decimal. For example, if the UIC is [313,
      31] then 13303833 is returned. (13303833 = 25 + 203 * 65536;
      Octal 31 = 25 decimal; Octal 313 = 203 decimal.)

   With POSIX style IDs enabled, geteuid returns the effective user
   ID of the calling process, and getuid returns the real user ID of
   the calling process.

   See also getegid and getgid.
 

3  Return_Value

   x                  The real user ID (POSIX IDs enabled), or the
                      member number from the current UIC or the full
                      UIC (POSIX IDs disabled).
 

2  getw
   Returns characters from a specified file.

   Format

     #include  <stdio.h>

     int getw  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A pointer to the file to be accessed.
 

3  Description
   The getw function returns the next four characters from the
   specified input file as an int.
 

3  Return_Values

   x                  The next four characters, in an int.
   EOF                Indicates that the end-of-file was encountered
                      during the retrieval of any of the four
                      characters and all four characters were
                      lost. Since EOF is an acceptable integer,
                      use feof and ferror to check the success of
                      the function.
 

2  getwc
   Reads the next character from a specified file, and converts it
   to a wide-character code.

   Format

     #include  <wchar.h>

     wint_t getwc  (FILE *file_ptr);
 

3  Argument
 

file_ptr

   A pointer to the file to be accessed.
 

3  Description
   Since getwc is implemented as a macro, a file pointer argument
   with side effects (for example getwc (*f++)) might be evaluated
   incorrectly. In such a case, use the fgetwc function instead. See
   the fgetwc function.
 

3  Return_Values

   n                  The returned character.
   WEOF               Indicates the end-of-file or an error. If an
                      error occurs, the function sets errno. For a
                      list of the values set by this function, see
                      fgetwc.
 

2  getwchar
   Reads a single wide character from the standard input (stdin).

   Format

     #include  <wchar.h>

     wint_t getwchar  (void);
 

3  Description
   The getwchar function is identical to fgetwc(stdin).
 

3  Return_Values

   x                  The next character from stdin, converted to
                      wint_t.
   WEOF               Indicates the end-of-file or an error. If an
                      error occurs, the function sets errno. For a
                      list of the values set by this function, see
                      fgetwc.
 

2  getyx
   Puts the (y,x) coordinates of the current cursor position on win
   in the variables y and x.

   Format

     #include  <curses.h>

     getyx  (WINDOW *win, int y, int x);
 

3  Arguments
 

win

   Must be a pointer to the window.
 

y

   Must be a valid lvalue.
 

x

   Must be a valid lvalue.
 

2  glob
   Returns a list of existing files for a user supplied pathname
   (with optional wildcards).

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <glob.h>

     int glob  (const char *pattern, int flags, int (*errfunc)(const 
               char *epath, int eerrno), glob_t *pglob);
 

3  Function_Variants
   The glob function has variants named _glob32 and _glob64 for use
   with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

pattern

   The pattern string to match with accessible files and pathnames.
   This pattern can have wildcards.
 

flags

   Controls the customizable behavior of the glob function.
 

errfunc

   An optional function that, if specified, is called when the glob
   function detects an error condition, or if not specified, is
   NULL.
 

epath

   First argument of the optional errfunc function, epath is the
   pathname that failed because a directory could not be opened or
   read.
 

eerrno

   Second argument of the optional errfunc function, eerrno is the
   errno value from a failure specified by the epath argument as set
   by the opendir, readdir, or stat functions.
 

pglob

   Pointer to a glob_t structure that returns the matching
   accessible existing filenames. The structure is allocated by the
   caller. The array of structures containing the located filenames
   that match the pattern argument are stored by the glob function
   into the structure. The last entry is a NULL pointer.

   The structure type glob_t is defined in the <glob.h> header file
   and includes at least the following members:

   size_t   gl_pathc    //Count of paths matched by pattern.
   char **  gl_pathv    //Pointer to a list of matched pathnames.
   size_t   gl_offs     //Slots to reserve at the beginning of gl_pathv.
 

3  Description
   The glob function constructs a list of accessible files that
   match the pattern argument.

   The glob function operates in one of two modes: UNIX mode or
   OpenVMS mode.

   You can select UNIX mode explicitly by enabling the feature
   logical DECC$GLOB_UNIX_STYLE, which is disabled by default.

   The glob function defaults to OpenVMS mode unless one of the
   following conditions is met (in which case glob uses UNIX mode):

   o  The DECC$GLOB_UNIX_STYLE is enabled.

   o  The DECC$FILENAME_UNIX_ONLY feature logical is enabled.

   o  The glob function checks the specified pattern for pathname
      indications, such as directory delimiters, and determines it
      to be a UNIX style pathname.

   OpenVMS mode

   This mode allows an OpenVMS programmer to give an OpenVMS style
   pattern to the glob function and get expected OpenVMS style
   output. The OpenVMS style pattern is what a user would expect
   from DCL commands or as input to the SYS$PARSE and SYS$SEARCH
   system routines.

   In this mode, you can use any of the expected OpenVMS wildcards
   (see the OpenVMS documentation for additional information).

   OpenVMS mode does not support the UNIX wildcard ?, or [] pattern
   matching. OpenVMS users expect [] to be available as directory
   delimiters.

   Some additional behavior differences between OpenVMS mode and
   UNIX mode:

   o  OpenVMS mode outputs full file specifications, not relative
      ones, as in UNIX mode.

   o  The GLOB_MARK flag is ignored in OpenVMS mode because it
      is not meaningful to append a slash (/)  to a directory on
      OpenVMS.

   For example:

   Sample pattern input      Sample output

   [.SUBDIR1]A.TXT           DEV:[DIR.SUBDIR1]A.TXT;1
   [.SUB*]%.*                DEV:[DIR.SUBDIR1]A.TXT;1

   UNIX mode

   You can enable this mode explicitly with:

   $ DEFINE DECC$GLOB_UNIX_STYLE ENABLE

   UNIX mode is also enabled if the DECC$FILENAME_UNIX_ONLY feature
   logical is set, or if the glob function determines that the
   specified pattern looks like a UNIX style pathname.

   In UNIX mode, the glob function follows the X/Open specification
   where possible.

   For example:

   Sample pattern input      Sample output

   ./a/b/c                   ./a/b/c
   ./?/b/*                   ./a/b/c
   [a-c]                     c

   Standard Description

   The glob function matches all accessible pathnames against this
   pattern and develops a list of all pathnames that match. To
   have access to a pathname, the glob function requires search
   permission on every component of a pathname except the last, and
   read permission on each directory of any filename component of
   the pattern argument.

   The glob function stores the number of matched pathnames and a
   pointer to a list of pointers to pathnames in the pglob argument.
   The pathnames are sorted, based on the setting of the LC_COLLATE
   category in the current locale. The first pointer after the last
   pathname is NULL. If the pattern does not match any pathnames,
   the returned number of matched pathnames is 0.

   It is the caller's responsibility to create the structure pointed
   to by the pglob argument. The glob function allocates other space
   as needed. The globfree function frees any space associated with
   the pglob argument as a result of a previous call to the glob
   function.

   The flags argument is used to control the behavior of the glob
   function. The flags value is the bitwise inclusive OR (|) of any
   of the following constants, which are defined in the <glob.h>
   header file:

   GLOB_APPEND  Appends pathnames located with this call to any
                pathnames previously located.
   GLOB_DOOFFS  Uses the gl_offs structure to specify the number
                of NULL pointers to add to the beginning of the gl_
                pathv component of the pglob argument.
   GLOB_ERR     Causes the glob function to return when it
                encounters a directory that it cannot open or
                read. If the GLOB_ERR flag is not set, the glob
                function continues to find matches if it encounters
                a directory that it cannot open or read.
   GLOB_MARK    Specifies that each pathname that is a directory
                should have a slash (/)  appended. GLOB_MARK is
                ignored in OpenVMS mode because it is not meaningful
                to append a slash to a directory on OpenVMS systems.
   GLOB_        If the pattern argument does not match any pathname,
   NOCHECK      then the glob function returns a list consisting
                only of the pattern argument, and the number of
                matched pathnames is 1.
   GLOB_        If the GLOB_NOESCAPE flag is set, a backslash (\)
   NOESCAPE     cannot be used to escape metacharacters.

   The GLOB_APPEND flag can be used to append a new set of pathnames
   to those found in a previous call to the glob function. The
   following rules apply when two or more calls to the glob function
   are made with the same value of the pglob argument, and without
   intervening calls to the globfree function:

   o  If the application sets the GLOB_DOOFFS flag in the first call
      to the glob function, then it is also set in the second call,
      and the value of the gl_offs field of the pglob argument is
      not modified between the calls.

   o  If the application did not set the GLOB_DOOFFS flag in the
      first call to the glob function, then it is not set in the
      second call.

   o  After the second call, pglob->gl_pathv points to a list
      containing the following:

      -  Zero or more NULLs, as specified by the GLOB_DOOFFS flag
         and pglob->gl_offs.

      -  Pointers to the pathnames that were in the pglob->gl_pathv
         list before the call, in the same order as after the first
         call to the glob function.

      -  Pointers to the new pathnames generated by the second call,
         in the specified order.

   o  The count returned in the pglob->gl_offs argument is the total
      number of pathnames from the two calls.

   o  The application should not modify the pglob->gl_pathc or
      pglob->gl_pathv fields between the two calls.

   On successful completion, the glob function returns a value of 0
   (zero). The pglob->gl_pathc field returns the number of matched
   pathnames and the pglob->gl_pathv field contains a pointer to
   a NULL-terminated list of matched and sorted pathnames. If the
   number of matched pathnames in the pglob->gl_pathc argument is 0
   (zero), the pointer in the pglob->gl_pathv argument is undefined.

   If the glob function terminates because of an error, the function
   returns one of the nonzero constants GLOB_ABORTED, GLOB_NOMATCH,
   or GLOB_NOSPACE, defined in the <glob.h> header file. In this
   case, the pglob argument values are still set as defined above.

   If, during the search, a directory is encountered that cannot
   be opened or read and the errfunc argument value is not NULL,
   the glob function calls errfunc with the two arguments epath and
   eerno:

      epath-The pathname that failed because a directory could not
      be opened or read.
      eerno-The errno value from a failure specified by the epath
      argument as set by the opendir, readdir, or stat functions.

   If errfunc is called and returns nonzero, or if the GLOB_ERR flag
   is set in flags, the glob function stops the scan and returns
   GLOB_ABORTED after setting the pglob argument to reflect the
   pathnames already scanned. If GLOB_ERR is not set and either
   errfunc is NULL or errfunc returns zero, the error is ignored.

   No errno values are returned.

   See also globfree, readdir, and stat.
 

3  Return_Values

   0                  Successful completion.
   GLOB_ABORTED       The scan was stopped because GLOB_ERROR was
                      set or errfunc returned a nonzero value.
   GLOB_NOMATCH       The pattern does not match any existing
                      pathname, and GLOB_NOCHECK was not set in
                      flags.
   GLOB_NOSPACE       An attempt to allocate memory failed.
 

2  globfree
   Frees any space associated with the pglob argument resulting from
   a previous call to the glob function.

   Format

     #include  <glob.h>

     void globfree  (glob_t *pglob);
 

3  Function_Variants
   The globfree function has variants named _globfree32 and _
   globfree64 for use with 32-bit and 64-bit pointer sizes,
   respectively.
 

3  Argument
 

pglob

   Pointer to a previously allocated glob_t structure.
 

3  Description
   The globfree function frees any space associated with the pglob
   argument resulting from a previous call to the glob function. The
   globfree function returns no value.
 

2  gmtime
   Converts time units to the broken-down UTC time.

   Format

     #include  <time.h>

     struct tm *gmtime  (const time_t *timer);

     struct tm *gmtime_r  (const time_t *timer, struct tm *result);  
                          (ISO POSIX-1)
 

3  Function_Variants
   Compiling with the _DECC_V4_SOURCE and _VMS_V6_SOURCE feature-
   test macros defined enables a local-time-based entry point to
   the gmtime_r function that is equivalent to the behavior before
   OpenVMS Version 7.0.
 

3  Arguments
 

timer

   Points to a variable that specifies a time value in seconds since
   the Epoch.
 

result

   A pointer to a tm structure where the result is stored.

   The tm structure is defined in the <time.h> header, and is also
   shown in tm Structure in the description of localtime.
 

3  Description
   The gmtime and gmtime_r functions convert the time (in seconds
   since the Epoch) pointed to by timer into a broken-down time,
   expressed as Coordinated Universal Time (UTC), and store it in a
   tm structure.

   The difference between the gmtime_r and gmtime functions is that
   the former puts the result into a user-specified tm structure
   where the result is stored. The latter puts the result into
   thread-specific static memory allocated by the Compaq C RTL,
   and which is overwritten by subsequent calls to gmtime; you must
   make a copy if you want to save it.

   On success, gmtime returns a pointer to the tm structure; gmtime_
   r returns its second argument. On failure, these functions return
   the NULL pointer.

                                  NOTE

      Generally speaking, UTC-based time functions can affect in-
      memory time-zone information, which is processwide data.
      However, if the system time zone remains the same during
      the execution of the application (which is the common case)
      and the cache of timezone files is enabled (which is the
      default), then the _r variant of the time functions asctime_
      r, ctime_r, gmtime_r and localtime_r, is both thread-safe
      and AST-reentrant.

      If, however, the system time zone can change during the
      execution of the application or the cache of timezone files
      is not enabled, then both variants of the UTC-based time
      functions belong to the third class of functions, which are
      neither thread-safe nor AST-reentrant.
 

3  Return_Values

   x                  Pointer to a tm structure.
   NULL               Indicates an error; errno is set to the
                      following value:

                      o  EINVAL - The timer argument is NULL.
 

2  gsignal
   Generates a specified software signal, which invokes the action
   routine established by a signal, ssignal, or sigvec function.

   Format

     #include  <signal.h>

     int gsignal  (int sig [, int sigcode]);
 

3  Arguments
 

sig

   The signal to be generated.
 

sigcode

   An optional signal code. For example, signal SIGFPE-the
   arithmetic trap signal-has 10 different codes, each representing
   a different type of arithmetic trap.

   The signal codes can be represented by mnemonics or numbers. The
   arithmetic trap codes are represented by the numbers 1 to 10, but
   the SIGILL codes are represented by the numbers 0 to 2. The code
   values are defined in the <signal.h> header file.
 

3  Description
   Calling the gsignal function has one of the following results:

   o  If gsignal specifies a sig argument that is outside the range
      defined in the <signal.h> header file, then gsignal returns 0
      and sets errno to EINVAL.

   o  If signal, ssignal, or sigvec establishes SIG_DFL (default
      action) for the signal, then gsignal does not return. The
      image is exited with the OpenVMS error code corresponding to
      the signal.

   o  If signal, ssignal, or sigvec establishes SIG_IGN (ignore
      signal) as the action for the signal, then gsignal returns its
      argument, sig.

   o  signal, ssignal, or sigvec must be used to establish an action
      routine for the signal. That function is called and its return
      value is returned by gsignal.

   See the Error and Signal Handling chapter of the C RTL Reference
   Manual for more information.

   See also raise, signal, ssignal, and sigvec.
 

3  Return_Values

   0                  Indicates a sig argument that is outside the
                      range defined in the <signal.h> header file;
                      errno is set to EINVAL.
   sig                Indicates that SIG_IGN (ignore signal) has
                      been established as the action for the signal.
   x                  Indicates that signal, ssignal, or sigvec has
                      established an action function for the signal.
                      That function is called, and its return value
                      is returned by gsignal.
 

2  hypot
   Returns the length of the hypotenuse of a right triangle.

   Format

     #include  <math.h>

     double hypot  (double x, double y);

     float hypotf  (float x, float y); (Integrity servers, Alpha)

     long double hypotl  (long double x, long double y);             
                         (Integrity servers, Alpha)
 

3  Arguments
 

x

   A real value.
 

y

   A real value.
 

3  Description
   The hypot functions return the length of the hypotenuse of a
   right triangle, where x and y represent the perpendicular sides
   of the triangle. The length is calculated as:

   sqrt(x2 + y2)

   On overflow, the return value is undefined, and errno is set to
   ERANGE.
 

3  Return_Values

   x                  The length of the hypotenuse.
   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
   0                  Underflow occurred; errno is set to ERANGE.
   NaN                x or y is NaN; errno is set to EDOM.
 

2  iconv
   Converts characters coded in one codeset to characters coded in
   another codeset.

   Format

     #include  <iconv.h>

     size_t iconv  (iconv_t cd, const char **inbuf, size_t           
                   *inbytesleft, char **outbuf, size_t               
                   *outbytesleft);
 

3  Arguments
 

cd

   A conversion descriptor. This is returned by a successful call to
   iconv_open.
 

inbuf

   A pointer to a variable that points to the first character in the
   input buffer.
 

inbytesleft

   Initially, this argument is a pointer to a variable that
   indicates the number of bytes to the end of the input buffer
   (inbuf). When the conversion is completed, the variable indicates
   the number of bytes in inbuf not converted.
 

outbuf

   A pointer to a variable that points to the first available byte
   in the output buffer. The output buffer contains the converted
   characters.
 

outbytesleft

   Initially, this argument is a pointer to a variable that
   indicates the number of bytes to the end of the output buffer
   (outbuf). When the conversion is completed, the variable
   indicates the number of bytes left in outbuf.
 

3  Description
   The iconv function converts characters in the buffer pointed
   to by inbuf to characters in another code set. The resulting
   characters are stored in the buffer pointed to by outbuf. The
   conversion type is specified by the conversion descriptor cd.
   This descriptor is returned from a successful call to iconv_open.

   If an invalid character is found in the input buffer, the
   conversion stops after the last successful conversion. The
   variable pointed to by inbytesleft is updated to reflect the
   number of bytes in the input buffer that are not converted. The
   variable pointed to by outbytesleft is updated to reflect the
   number of bytes remaining in the output buffer.
 

3  Return_Values

   x                  Number of nonidentical conversions performed.
                      Indicates successful conversion. In most
                      cases, 0 is returned.
   (size_t) -1        Indicates an error condition. The function
                      sets errno to one of the following:

                      o  EBADF - The cd argument is not a valid
                         conversion descriptor.

                      o  EILSEQ - The conversion stops when an
                         invalid character detected.

                      o  E2BIG - The conversion stops because of
                         insufficient space in the output buffer.

                      o  EINVAL - The conversion stops because of
                         an incomplete character at the end of the
                         input buffer.
 

2  iconv_close
   Deallocates a specified conversion descriptor and the resources
   allocated to the descriptor.

   Format

     #include  <iconv.h>

     int iconv_close  (iconv_t cd);
 

3  Argument
 

cd

   The conversion descriptor to be deallocated. A conversion
   descriptor is returned by a successful call to iconv_open.
 

3  Return_Values

   0                  Indicates that the conversion descriptor was
                      successfully deallocated.
   -1                 Indicates an error occurred. The function sets
                      errno to one of the following:

                      o  EBADF - The cd argument is not a valid
                         conversion descriptor.

                      o  EVMSERR - Nontranslatable OpenVMS error
                         occur. vaxc$errno contains the VMS error
                         code.
 

2  iconv_open
   Allocates a conversion descriptor for a specified codeset
   conversion.

   Format

     #include  <iconv.h>

     iconv_t iconv_open  (const char *tocode, const char *fromcode);
 

3  Arguments
 

tocode

   The name of the codeset to which characters are converted.
 

fromcode

   The name of the source codeset. See the "Developing International
   Software" chapter of the HP C RTL Reference Manual for
   information on obtaining a list of currently available codesets
   or for details on adding new codesets.
 

3  Return_Values

   x                  A conversion descriptor. Indicates the call
                      was successful. This descriptor is used in
                      subsequent calls to iconv
   (iconv_t) -1       Indicates an error occurred. The function sets
                      errno to one of the following:

                      o  EMFILE - The process does not have enough
                         I/O channels to open a file.

                      o  ENOMEM - Insufficient space is available.

                      o  EINVAL - The conversion specified by
                         fromcode and tocode is not supported.

                      o  EVMSERR - Nontranslatable OpenVMS error
                         occur. vaxc$errno contains the OpenVMS
                         error code. A value of SS$_BADCHKSUM in
                         vaxc$errno indicates that a conversion
                         table file was found, but its contents is
                         corrupted. A value of SS$_IDMISMATCH in
                         vaxc$errno indicates that the conversion
                         table file version does not match the
                         version of the C Run-Time Library.
 

3  Example

       #include <stdio.h>
       #include <iconv.h>
       #include <errno.h>

       int main()
       {
         /* Declare variables to be used                      */

         char fromcodeset[30];
         char tocodeset[30];
         int iconv_opened;
         iconv_t iconv_struct;       /* Iconv descriptor      */

         /* Initialize variables                              */

         sprintf(fromcodeset, "DECHANYU");
         sprintf(tocodeset, "EUCTW");
         iconv_opened = FALSE;

         /* Attempt to create a conversion descriptor for the */
         /* codesets specified. If the return value from      */
         /* iconv_open is -1 then an error has occurred.      */
         /*  Check the value of errno.                        */

         if ((iconv_struct = iconv_open(tocodeset, fromcodeset))
            == (iconv_t) - 1) {

             /* Check the value of errno                      */

             switch (errno) {
             case EMFILE:
             case ENFILE:
                 printf("Too many iconv conversion files open\n");
                 break;

             case ENOMEM:
                 printf("Not enough memory\n");
                 break;

             case EINVAL:
                 printf("Unsupported conversion\n");
                 break;

             default:
                 printf("Unexpected error from iconv_open\n");
                 break;
            }
         }
         else

             /* Successfully allocated a conversion descriptor   */

             iconv_opened = TRUE;

         /*  Was a conversion descriptor allocated               */

          if (iconv_opened) {

             /* Attempt to deallocate the conversion descriptor. */
             /* If iconv_close returns -1 then an error has      */
             /* occurred.                                        */

             if (iconv_close(iconv_struct) == -1) {

                 /* An error occurred. Check the value of errno  */

                 switch (errno) {
                 case EBADF:
                     printf("Conversion descriptor is invalid\n");
                     break;
                 default:
                     printf("Unexpected error from iconv_close\n");
                     break;
                 }
             }
         }
         return (EXIT_FAILURE);
       }
 

2  ilogb
   Returns the exponent part of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     int ilogb  (double x);

     int ilogbf  (float x);

     int ilogbl  (long double x);
 

3  Argument
 

x

   A real value.
 

3  Description
   The ilogb functions return the exponent part of their argument
   x. Formally, the return value is the integral part of logr|x| as
   a signed integral value, for nonzero x, where r is the radix of
   the machine's floating-point arithmetic, which is the value of
   FLT_RADIX defined in <float.h>.
 

3  Return_Values

   n                  Upon success, the exponent part of x as a
                      signed integer value. These functions are
                      equivalent to calling the corresponding logb
                      function and casting the returned value to
                      type int.
 

2  [w]inch
   Return the character at the current cursor position on the
   specified window without making changes to the window. The inch
   function acts on the stdscr window.

   Format

     #include  <curses.h>

     char inch();

     char winch  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Return_Values

   x                  The returned character.
   ERR                Indicates an input error.
 

2  index
   Searches for a character in a string.

   Format

     #include  <strings.h>

     char *index  (const char *s, int c);
 

3  Function_Variants
   The index function has variants named _index32 and _index64 for
   use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

s

   The string to search.
 

c

   The character to search for.
 

3  Description
   The index function is identical to the strchr function, and is
   provided for compatibility with some UNIX implementations.
 

2  initscr
   Initializes the terminal-type data and all screen functions. You
   must call initscr before using any of the curses functions.

   Format

     #include  <curses.h>

     void initscr  (void);
 

3  Description
   The OpenVMS Curses version of the initscr function clears the
   screen before doing the initialization. The BSD-based Curses
   version does not.
 

2  initstate
   Initializes random-number generators.

   Format

     #include  <stdlib.h>

     char *initstate  (unsigned int seed, char *state, int size);
 

3  Arguments
 

seed

   An initial seed value.
 

state

   Pointer to an array of state information.
 

size

   The size of the state information array.
 

3  Description
   The initstate function initializes random-number generators. It
   lets you initialize, for future use, a state array passed as an
   argument. The size, in bytes, of the state array is used by the
   initstate function to decide how sophisticated a random-number
   generator to use; the larger the state array, the more random the
   numbers.

   Values for the amount of state information are 8, 32, 64, 128,
   and 256 bytes. Amounts less than 8 bytes generate an error, while
   other amounts are rounded down to the nearest known value.

   The seed argument specifies a starting point for the random-
   number sequence and provides for restarting at the same point.
   The initstate function returns a pointer to the previous state
   information array.

   Once you initialize a state, the setstate function allows rapid
   switching between states. The array defined by the state argument
   is used for further random-number generation until the initstate
   function is called or the setstate function is called again. The
   setstate function returns a pointer to the previous state array.

   After initialization, you can restart a state array at a
   different point in one of two ways:

   o  Use the initstate function with the desired seed argument,
      state array, and size of the array.

   o  Use the setstate function with the desired state, followed by
      the srandom function with the desired seed. The advantage of
      using both functions is that you do not have to save the state
      array size once you initialize it.

   See also setstate, srandom, and random.
 

3  Return_Values

   x                  A pointer to the previous state array
                      information.
   0                  Indicates an error. Call made with less than 8
                      bytes of state information. Further specified
                      in the global errno.
 

2  [w]insch
   Insert a character at the current cursor position in the
   specified window. The insch function acts on the stdscr window.

   Format

     #include  <curses.h>

     int insch  (char ch);

     int winsch  (WINDOW *win, char ch);
 

3  Arguments
 

win

   A pointer to the window.
 

ch

   The character to be inserted.
 

3  Description
   After the character is inserted, each character on the line
   shifts to the right, and the last character in the line is
   deleted. For more information, see the scrollok function.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function makes the screen
                      scroll illegally.
 

2  [w]insertln
   Insert a line above the line containing the current cursor
   position. The insertln function acts on the stdscr window.

   Format

     #include  <curses.h>

     int insertln();

     int winsertln  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Description
   The current line and every line below it shifts down, and the
   bottom line disappears. The inserted line is blank and the
   current (y,x) coordinates remain the same. For more information,
   see the scrollok function.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function makes the screen
                      scroll illegally.
 

2  [w]insstr
   Insert a string at the current cursor position in the specified
   window. The insstr function acts on the stdscr window.

   Format

     #include  <curses.h>

     int insstr  (char *str);

     int winsstr  (WINDOW *win, char *str);
 

3  Arguments
 

win

   A pointer to the window.
 

str

   A pointer to the string to be inserted.
 

3  Description
   Each character after the string shifts to the right, and the last
   character disappears. These functions are specific to Compaq C
   for OpenVMS Systems and are not portable.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function makes the screen
                      scroll illegally. For more information, see
                      the scrollok function.
 

2  isalnum
   Indicates if a character is classed either as alphabetic or as a
   digit in the program's current locale.

   Format

     #include  <ctype.h>

     int isalnum  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char or must equal the value of the
   macro EOF. If it has any other value, the behavior is undefined.
 

3  Return_Values

   nonzero            If alphanumeric.
   0                  If not alphanumeric.
 

2  isalpha
   Indicates if a character is classed as an alphabetic character in
   the program's current locale.

   Format

     #include  <ctype.h>

     int isalpha  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char or must equal the value of the
   macro EOF. If it has any other value, the behavior is undefined.
 

3  Return_Values

   nonzero            If alphabetic.
   0                  If not alphabetic.
 

2  isapipe
   Indicates if a specified file descriptor is associated with a
   pipe.

   Format

     #include  <unixio.h>

     int isapipe  (int file_desc);
 

3  Argument
 

file_desc

   A file descriptor.
 

3  Description
   For more information about pipes, see the "Subprocess Functions"
   chapter of the HP C RTL Reference Manual.
 

3  Return_Values

   1                  Indicates an association with a pipe.
   0                  Indicates no association with a pipe.
   -1                 Indicates an error (for example, if the file
                      descriptor is not associated with an open
                      file).
 

2  isascii
   Indicates if a character is an ASCII character.

   Format

     #include  <ctype.h>

     int isascii  (int character);
 

3  Argument
 

character

   An object of type char.
 

3  Return_Values

   nonzero            If ASCII.
   0                  If not ASCII.
 

2  isatty
   Indicates if a specified file descriptor is associated with a
   terminal.

   Format

     #include  <unistd.h>

     int isatty  (int file_desc);
 

3  Argument
 

file_desc

   A file descriptor.
 

3  Return_Values

   1                  If the file descriptor is associated with a
                      terminal.
   0                  If the file descriptor is not associated with
                      a terminal.
   -1                 Indicates an error (for example, if the file
                      descriptor is not associated with an open
                      file).
 

2  iscntrl
   Indicates if a character is classed as a control character in the
   program's current locale.

   Format

     #include  <ctype.h>

     int iscntrl  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char or must equal the value of the
   macro EOF. If it has any other value, the behavior is undefined.
 

3  Return_Values

   nonzero            If a control character.
   0                  If not a control character.
 

2  isdigit
   Indicates if a character is classed as a digit in the program's
   current locale.

   Format

     #include  <ctype.h>

     int isdigit  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char or must equal the value of the
   macro EOF. If it has any other value, the behavior is undefined.
 

3  Return_Values

   nonzero            If a decimal digit.
   0                  If not a decimal digit.
 

2  isgraph
   Indicates if a character is classed as a graphic character in the
   program's current locale.

   Format

     #include  <ctype.h>

     int isgraph  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char or must equal the value of the
   macro EOF. If it has any other value, the behavior is undefined.
 

3  Return_Values

   nonzero            If a graphic character.
   0                  If not a graphic character.
 

2  islower
   Indicates if a character is classed as a lowercase character in
   the program's current locale.

   Format

     #include  <ctype.h>

     int islower  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char or must equal the value of the
   macro EOF. If it has any other value, the behavior is undefined.
 

3  Return_Values

   nonzero            If a lowercase alphabetic character.
   0                  If not a lowercase alphabetic character.
 

2  isnan
   Test for a NaN. Returns 1 if the argument is NaN; 0 if not.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     int isnan  (double x);

     int isnanf  (float x);

     int isnanl  (long double x);
 

3  Argument
 

x

   A real value.
 

3  Description
   The isnan functions return the integer value 1 (TRUE) if x is NaN
   (the IEEE floating point reserved not-a-number value); otherwise,
   they return the value 0 (FALSE).
 

2  isprint
   Indicates if a character is classed as a printing character in
   the program's current locale.

   Format

     #include  <ctype.h>

     int isprint  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char or must equal the value of the
   macro EOF. If it has any other value, the behavior is undefined.
 

3  Return_Values

   nonzero            If a printing character.
   0                  If not a printing character.
 

2  ispunct
   Indicates if a character is classed as a punctuation character in
   the program's current locale.

   Format

     #include  <ctype.h>

     int ispunct  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char or must equal the value of the
   macro EOF. If it has any other value, the behavior is undefined.
 

3  Return_Values

   nonzero            If a punctuation character.
   0                  If not a punctuation character.
 

2  isspace
   Indicates if a character is classed as white space in the
   program's current locale; that is, if it is an ASCII space, tab
   (horizontal or vertical), carriage-return, form-feed, or new-line
   character.

   Format

     #include  <ctype.h>

     int isspace  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char or must equal the value of the
   macro EOF. If it has any other value, the behavior is undefined.
 

3  Return_Values

   nonzero            If a white-space character.
   0                  If not a white-space character.
 

2  isupper
   Indicates if a character is classed as an uppercase character in
   the program's current locale.

   Format

     #include  <ctype.h>

     int isupper  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char or must equal the value of the
   macro EOF. If it has any other value, the behavior is undefined.
 

3  Return_Values

   nonzero            If an uppercase alphabetic character.
   0                  If not an uppercase alphabetic character.
 

2  iswalnum
   Indicates if a wide character is classed either as alphabetic or
   as a digit in the program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswalnum  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of character must be
   representable as a wchar_t in the current locale, or must equal
   the value of the macro WEOF. If it has any other value, the
   behavior is undefined.
 

3  Return_Values

   nonzero            If alphanumeric.
   0                  If not alphanumeric.
 

2  iswalpha
   Indicates if a wide character is classed as an alphabetic
   character in the program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswalpha  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of wc must be representable
   as a wchar_t in the current locale, or must equal the value
   of the macro WEOF. If it has any other value, the behavior is
   undefined.
 

3  Return_Values

   nonzero            If alphabetic.
   0                  If not alphabetic.
 

2  iswcntrl
   Indicates if a wide character is classed as a control character
   in the program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswcntrl  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of wc must be representable
   as a wchar_t in the current locale, or must equal the value
   of the macro WEOF. If it has any other value, the behavior is
   undefined.
 

3  Return_Values

   nonzero            If a control character.
   0                  If not a control character.
 

2  iswctype
   Indicates if a wide character has a specified property.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswctype  (wint_t wc, wctype_t wc_prop);
 

3  Arguments
 

wc

   An object of type wint_t. The value of wc must be representable
   as a valid wide-character code in the current locale, or must
   equal the value of the macro WEOF. If it has any other value, the
   behavior is undefined.
 

wc_prop

   A valid property name in the current locale. This is set up by
   calling the wctype function.
 

3  Description
   The iswctype function tests whether wc has the character-class
   property wc_prop. Set wc_prop by calling the wctype function.

   See also wctype.
 

3  Return_Values

   nonzero            If the character has the property wc_prop.
   0                  If the character does not have the property
                      wc_prop.
 

3  Example

       #include <locale.h>
       #include <wchar.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>
       #include <ctype.h>

       /* This test will set up the "upper" character class using      */
       /* wctype() and then verify whether the characters 'a' and 'A'  */
       /* are members of this class                                    */

       #include <stdlib.h>

       main()
       {

           wchar_t w_char1,
                   w_char2;
           wctype_t ret_val;

           char *char1 = "a";
           char *char2 = "A";

           ret_val = wctype("upper");

           /* Convert char1 to wide-character format - w_char1 */

           if (mbtowc(&w_char1, char1, 1) == -1) {
              perror("mbtowc");
               exit(EXIT_FAILURE);
           }

           if (iswctype((wint_t) w_char1, ret_val))
               printf("[%C] is a member of the character class upper\n",
                       w_char1);
           else
            printf("[%C] is not a member of the character class upper\n",
                     w_char1);

           /* Convert char2 to wide-character format - w_char2 */

           if (mbtowc(&w_char2, char2, 1) == -1) {
               perror("mbtowc");
               exit(EXIT_FAILURE);
           }

           if (iswctype((wint_t) w_char2, ret_val))
               printf("[%C] is a member of the character class upper\n",
                       w_char2);
           else
            printf("[%C] is not a member of the character class upper\n",
                       w_char2);
       }

     Running the example program produces the following result:

       [a] is not a member of the character class upper
       [A] is a member of the character class upper
 

2  iswdigit
   Indicates if a wide character is classed as a digit in the
   program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswdigit  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of wc must be representable
   as a wchar_t in the current locale, or must equal the value
   of the macro WEOF. If it has any other value, the behavior is
   undefined.
 

3  Return_Values

   nonzero            If a decimal digit.
   0                  If not a decimal digit.
 

2  iswgraph
   Indicates if a wide character is classed as a graphic character
   in the program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswgraph  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of wc must be representable
   as a wchar_t in the current locale, or must equal the value
   of the macro WEOF. If it has any other value, the behavior is
   undefined.
 

3  Return_Values

   nonzero            If a graphic character.
   0                  If not a graphic character.
 

2  iswlower
   Indicates if a wide character is classed as a lowercase character
   in the program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswlower  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of wc must be representable
   as a wchar_t in the current locale, or must equal the value
   of the macro WEOF. If it has any other value, the behavior is
   undefined.
 

3  Return_Values

   nonzero            If a lowercase character.
   0                  If not a lowercase character.
 

2  iswprint
   Indicates if a wide character is classed as a printing character
   in the program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswprint  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of wc must be representable
   as a wchar_t in the current locale, or must equal the value
   of the macro WEOF. If it has any other value, the behavior is
   undefined.
 

3  Return_Values

   nonzero            If a printing character.
   0                  If not a printing character.
 

2  iswpunct
   Indicates if a wide character is classed as a punctuation
   character in the program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswpunct  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of wc must be representable
   as a wchar_t in the current locale, or must equal the value
   of the macro WEOF. If it has any other value, the behavior is
   undefined.
 

3  Return_Values

   nonzero            If a punctuation character.
   0                  If not a punctuation character.
 

2  iswspace
   Indicates if a wide character is classed as a space character in
   the program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswspace  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of wc must be representable
   as a wchar_t in the current locale, or must equal the value
   of the macro WEOF. If it has any other value, the behavior is
   undefined.
 

3  Return_Values

   nonzero            If a white-space character.
   0                  If not a white-space character.
 

2  iswupper
   Indicates if a wide character is classed as an uppercase
   character in the program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswupper  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of wc must be representable
   as a wchar_t in the current locale, or must equal the value
   of the macro WEOF. If it has any other value, the behavior is
   undefined.
 

3  Return_Values

   nonzero            If an uppercase character.
   0                  If not an uppercase character.
 

2  iswxdigit
   Indicates if a wide character is a hexadecimal digit (0 to 9, A
   to F, or a to f) in the program's current locale.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int iswxdigit  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t. The value of wc must be representable
   as a wchar_t in the current locale, or must equal the value
   of the macro WEOF. If it has any other value, the behavior is
   undefined.
 

3  Return_Values

   nonzero            If a hexadecimal digit.
   0                  If not a hexadecimal digit.
 

2  isxdigit
   Indicates if a character is a hexadecimal digit (0 to 9, A to F,
   or a to f) in the program's current locale.

   Format

     #include  <ctype.h>

     int isxdigit  (int character);
 

3  Argument
 

character

   An object of type int. The value of character must be
   representable as an unsigned char in the current locale, or must
   equal the value of the macro EOF. If it has any other value, the
   behavior is undefined.
 

3  Return_Values

   nonzero            If a hexadecimal digit.
   0                  If not a hexadecimal digit.
 

2  j0,j1,jn
   Compute Bessel functions of the first kind.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double j0  (double x);

     float j0f  (float x);

     long double j0l  (long double x);

     double j1  (double x);

     float j1f  (float x);

     long double j1l  (long double x);

     double jn  (int n, double x);

     float jnf  (int n, float x);

     long double jnl  (int n, long double x);
 

3  Arguments
 

x

   A real value.
 

n

   An integer.
 

3  Description
   The j0 functions return the value of the Bessel function of the
   first kind of order 0.

   The j1 functions return the value of the Bessel function of the
   first kind of order 1.

   The jn functions return the value of the Bessel function of the
   first kind of order n.

   The j1 and jn functions can result in an underflow as x gets
   small. The largest value of x for which this occurs is a function
   of n.
 

3  Return_Values

   x                  The relevant Bessel value of x of the first
                      kind.
   0                  The value of the x argument is too large, or
                      underflow occurred; errno is set to ERANGE.
   NaN                x is NaN; errno is set to EDOM.
 

2  jrand48
   Generates uniformly distributed pseudorandom-number sequences.
   Returns 48-bit signed, long integers.

   Format

     #include  <stdlib.h>

     long int jrand48  (unsigned short int xsubi[3]);
 

3  Argument
 

xsubi

   An array of three short ints that form a 48-bit integer when
   concatenated together.
 

3  Description
   The jrand48 function generates pseudorandom numbers using the
   linear congruential algorithm and 48-bit integer arithmetic.

   The function returns signed long integers uniformly distributed
   over the range of y values, such that -231 
   The function works by generating a sequence of 48-bit integer
   values, Xi, according to the linear congruential formula:

          Xn+1 = (aXn+c)mod m        n >= 0

   The argument m equals 248, so 48-bit integer arithmetic is

   performed. Unless you invoke the lcong48 function, the multiplier
   value a and the addend value c are:

         a = 5DEECE66D16 = 2736731631558

         c = B16 = 138

   The jrand48 function requires that the calling program pass an
   array as the xsubi argument, which for the first call must be
   initialized to the initial value of the pseudorandom-number
   sequence. Unlike the drand48 function, it is not necessary to
   call an initialization function prior to the first call.

   By using different arguments, jrand48 allows separate modules
   of a large program to generate several independent sequences of
   pseudorandom numbers. For example, the sequence of numbers that
   one module generates does not depend upon how many times the
   function is called by other modules.
 

3  Return_Value

   n                  Signed, long integers uniformly distributed
                      over the range -231  

2  kill
   Sends a signal to the process specified by a process ID.

   Format

     #include  <signal.h>

     int kill  (int pid, int sig);
 

3  Arguments
 

pid

   The process ID.
 

sig

   The signal code.
 

3  Description
   The kill function is restricted to C and C++ programs that
   include the main function.

   The kill function sends a signal to a process, as if the process
   had called raise. If the signal is not trapped or ignored by the
   target program, the program exits.

   OpenVMS VAX and Alpha implement different rules about what
   process you are allowed to send signals to. A program always has
   privileges to send a signal to a child started with vfork/exec.
   For other processes, the results are determined by the OpenVMS
   security model for your system.

   Because of an OpenVMS restriction, the kill function cannot
   deliver a signal to a target process that runs an image installed
   with privileges.

   Unless you have system privileges, the sending and receiving
   processes must have the same user identification code (UIC).

   On OpenVMS systems before Version 7.0, kill treats a signal value
   of 0 as if SIGKILL were specified.

   For OpenVMS Version 7.0 and higher systems, if you include
   <stdlib.h> and compile with the _POSIX_EXIT feature-test macro
   set, then:

   o  If the signal value is 0, kill validates the process ID but
      does not send any signals.

   o  If the process ID is not valid, kill returns -1 and sets errno
      to ESRCH.
 

3  Return_Values

   0                  Indicates that kill was successfully queued.
   -1                 Indicates errors. The receiving process may
                      have a different UIC and you are not a system
                      user, or the receiving process does not exist.
 

2  l64a
   Converts a long integer to a character string.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdlib.h>

     char *l64a  (long l);
 

3  Argument
 

l

   A long integer that is to be converted to a character string.
 

3  Description
   The a64l and l64a functions are used to maintain numbers stored
   in base-64 ASCII characters:

   o  a64l converts a character string to a long integer.

   o  l64a converts a long integer to a character string.

   Each character used to store a long integer represents a numeric
   value from 0 through 63. Up to six characters can be used to
   represent a long integer.

   The characters are translated as follows:

   o  A period (.)  represents 0.

   o  A slash (/)  represents 1.

   o  The numbers 0 through 9 represent 2 through 11.

   o  Uppercase letters A through Z represent 12 through 37.

   o  Lowercase letters a through z represent 38 through 63.

   The l64a function takes a long integer and returns a pointer to a
   corresponding base-64 notation of the least significant 32 bits.

   The value returned by l64a is a pointer to a thread-specific
   buffer whose contents are overwritten on subsequent calls from
   the same

   See also a64l.
 

3  Return_Value

   x                  Upon successful completion, a pointer to
                      the corresponding base-64 ASCII character-
                      string notation. If the l parameter is 0, l64a
                      returns a pointer to an empty string.
 

2  labs
   Returns the absolute value of an integer as a long int.

   Format

     #include  <stdlib.h>

     long int labs  (long int j);
 

3  Argument
 

j

   A value of type long int.
 

2  lchown
   Changes the user and group ownership of the specified file.

   Format

     #include  <unistd.h>

     int lchown  (const char *file_path, uid_t file_owner, gid_t    
                 file_group);
 

3  Arguments
 

file_path

   The name of the file for which you want to change the owner and
   group IDs.
 

file_owner

   The new user ID for the file.
 

file_group

   The new group ID for the file.
 

3  Description
   The lchown function changes the owner and/or group of the
   specified file (file_path). If the file is a symbolic link, the
   owner of the symbolic link is modified (in contrast to chown
   which would modify the file that the symbolic link points to).

   See also symlink, unlink, readlink, realpath, and lstat.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. errno is set to any errno
                      value returned by chown.
 

2  lcong48
   Initializes a 48-bit uniformly distributed pseudorandom-number
   sequence.

   Format

     #include  <stdlib.h>

     void lcong48  (unsigned short int param[7]);
 

3  Argument
 

param

   An array that in turn specifies the initial Xi, the multiplier
   value a, and the addend value c.
 

3  Description
   The lcong48 function generates pseudorandom numbers using the
   linear congruential algorithm and 48-bit integer arithmetic.

   You can use lcong48 to initialize the random number generator
   before you call any of the following functions:

      drand48
      lrand48
      mrand48

   The lcong48 function specifies the initial Xi value, the
   multiplier value a, and the addend value c. The param array
   elements specify the following:

   param[0-   Xi
   2]
   param[3-   Multiplier a value
   5]
   param[6]   16-bit addend c value

   After lcong48 has been called, a subsequent call to either
   srand48 or seed48 restores the standard a and c as specified
   previously.

   The lcong48 function does not return a value.

   See also drand48, lrand48, mrand48, srand48, and seed48.
 

2  ldexp
   Returns its first argument multiplied by 2 raised to the power of
   its second argument; that is, x(2n).

   Format

     #include  <math.h>

     double ldexp  (double x, int n);

     float ldexp  (float x, int n); (Integrity servers, Alpha)

     long double ldexp  (long double x, int n);                     
                        (Integrity servers, Alpha)
 

3  Arguments
 

x

   A base value of type double, float, or long double that is to be
   multiplied by 2n.
 

n

   The integer exponent value to which 2 is raised.
 

3  Return_Values

   x(2n)              The first argument multiplied by 2 raised to

                      the power of the second argument.
   0                  Underflow occurred; errno is set to ERANGE.
   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
   NaN                x is NaN; errno is set to EDOM.
 

2  ldiv
   Returns the quotient and the remainder after the division of its
   arguments.

   Format

     #include  <stdlib.h>

     ldiv_t ldiv  (long int numer, long int denom);
 

3  Arguments
 

numer

   A numerator of type long int.
 

denom

   A denominator of type long int.
 

3  Description
   The type ldiv_t is defined in the <stdlib.h> header file as
   follows:

   typedef struct
           {
                long   quot, rem;
           } ldiv_t;

   See also div.
 

2  leaveok
   Signals Curses to leave the cursor at the current coordinates
   after an update to the window.

   Format

     #include  <curses.h>

     leaveok  (WINDOW *win, bool boolf);
 

3  Arguments
 

win

   A pointer to the window.
 

boolf

   A Boolean TRUE or FALSE value. If boolf is TRUE, the cursor
   remains in place after the last update and the coordinate setting
   on win changes accordingly. If boolf is FALSE, the cursor moves
   to the currently specified (y,x) coordinates of win.
 

3  Description
   The leaveok function defaults to moving the cursor to the current
   coordinates of win. The bool type is defined in the <curses.h>
   header file as follows:

   #define bool int
 

2  lgamma
   Computes the logarithm of the gamma function.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double lgamma  (double x);

     float lgammaf  (float x);

     long double lgammal  (long double x);
 

3  Argument
 

x

   A real number. x cannot be 0, a negative integer, or Infinity.
 

3  Description
   The lgamma functions return the logarithm of the absolute value
   of gamma of x, or ln(|G(x)|), where G is the gamma function.

   The sign of gamma of x is returned in the external integer
   variable signgam. The x argument cannot be 0, a negative integer,
   or Infinity.
 

3  Return_Values

   x                  The logarithmic gamma of the x argument.
   -HUGE_VAL          The x argument is a negative integer; errno is
                      set to ERANGE.
   NaN                The x argument is NaN; errno is set to EDOM.
   0                  Underflow occurred; errno is set to ERANGE.
   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
 

2  link
   Creates a new link (directory entry) for an existing file. This
   function is supported only on volumes that have hard link counts
   enabled.

   Format

     #include  <unistd.h>

     link  (const char *path1, const char *path2);
 

3  Arguments
 

path1

   Pointer to a pathname naming an existing file.
 

path2

   Pointer to a pathname naming the new directory entry to be
   created.
 

3  Description
   The link function atomically creates a new link for the existing
   file, and the link count of the file is incremented by one.

   The link function can be used on directory files.

   If link fails, no link is created and the link count of the file
   remains unchanged.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EEXIST - The link named by path2 exists.

                      o  EFTYPE - Wildcards appear in either path1
                         or path2.

                      o  EINVAL - One or both arguments specify a
                         syntactically invalid pathname.

                      o  ENAMETOOLONG - The length of path1 or path2
                         exceeds PATH_MAX, or a pathname component
                         is longer than NAME_MAX.

                      o  EXDEV - The link named by path2 and
                         the filenamed by path1 are on different
                         devices.
 

2  localeconv
   Sets the members of a structure of type struct lconv with values
   appropriate for formatting numeric quantities according to the
   rules of the current locale.

   Format

     #include  <locale.h>

     struct lconv *localeconv  (void);
 

3  Description
   The localeconv function returns a pointer to the lconv structure
   defined in the <locale.h> header file. This structure should
   not be modified by the program. It is overwritten by calls to
   localeconv, or by calls to the setlocale function that change the
   LC_NUMERIC, LC_MONETARY, or LC_ALL categories.

   The members of the structure are:

   Member                 Description

   char *decimal_point    The radix character.
   char *thousands_sep    The character used to separate groups of
                          digits.
   char *grouping         The string that defines how digits are
                          grouped in nonmonetary values.
   char *int_curr_symbol  The international currency symbol.
   char *currency_symbol  The local currency symbol.
   char *mon_decimal_     The radix character used to format
   point                  monetary values.
   char *mon_thousands_   The character used to separate groups of
   sep                    digits in monetary values.
   char *mon_grouping     The string that defines how digits are
                          grouped in a monetary value.
   char *positive_sign    The string used to indicate a nonnegative
                          monetary value.
   char *negative_sign    The string used to indicate a negative
                          monetary value.
   char int_frac_digits   The number of digits displayed after
                          the radix character in a monetary value
                          formatted with the international currency
                          symbol.
   char frac_digits       The number of digits displayed after the
                          radix character in a monetary value.
   char p_cs_precedes     For positive monetary values, this is
                          set to 1 if the local or international
                          currency symbol precedes the number, and
                          it is set to 0 if the symbol succeeds the
                          number.
   char p_sep_by_space    For positive monetary values, this is
                          set to 0 if there is no space between the
                          currency symbol and the number. It is set
                          to 1 if there is a space, and it is set to
                          2 if there is a space between the symbol
                          and the sign string.
   char n_cs_precedes     For negative monetary values, this is
                          set to 1 if the local or international
                          currency symbol precedes the number, and
                          it is set to 0 if the symbol succeeds the
                          number.
   char n_sep_by_space    For negative monetary values, this is
                          set to 0 if there is no space between the
                          currency symbol and the number. It is set
                          to 1 if there is a space, and it is set to
                          2 if there is a space between the symbol
                          and the sign string.
   char p_sign_posn       An integer used to indicate where the
                          positive_sign string should be placed for
                          a nonnegative monetary quantity.
   char n_sign_posn       An integer used to indicate where the
                          negative_sign string should be placed for
                          a negative monetary quantity.

   Members of the structure of type char* are pointers to strings,
   any of which (except decimal_point) can point to "", indicating
   that the associated value is not available in the current locale
   or is zero length. Members of the structure of type char are
   positive numbers, any of which can be CHAR_MAX, indicating that
   the associated value is not available in the current locale.
   CHAR_MAX is defined in the <limits.h> header file.

   Be aware that the value of the CHAR_MAX macro in the <limits.h>
   header depends on whether the program is compiled with the
   /UNSIGNED_CHAR qualifier:

   o  Use the CHAR_MAX macro as an indicator of a nonavailable value
      in the current locale only if the program is compiled without
      /UNSIGNED_CHAR (/NOUNSIGNED_CHAR is the default).

   o  If the program is compiled with /UNSIGNED_CHAR, use the SCHAR_
      MAX macro instead of the CHAR_MAX macro.

   In /NOUNSIGNED_CHAR mode, the values of CHAR_MAX and SCHAR_MAX
   are the same; therefore, comparison with SCHAR_MAX gives correct
   results regardless of the /[NO]UNSIGNED_CHAR mode used.

   The members grouping and mon_grouping point to a string that
   defines the size of each group of digits when formatting a
   number. Each group size is separated by a semicolon (;). For
   example, if grouping points to the string 5;3 and the thousands_
   sep character is a comma (,), the number 123450000 would be
   formatted as 1,234,50000.

   The elements of grouping and mon_grouping are interpreted as
   follows:

   Value      Interpretation

   CHAR_MAX   No further grouping is performed.
   0          The previous element is to be used repeatedly for the
              remainder of the digits.
   other      The integer value is the number of digits that comprise
              the current group. The next element is examined to
              determine the size of the next group of digits before
              the current group.

   The values of p_sign_posn and n_sign_posn are interpreted as
   follows:

   Value    Interpretation

   0        Parentheses surround the number and currency symbol.
   1        The sign string precedes the number and currency symbol.
   2        The sign string succeeds the number and currency symbol.
   3        The sign string immediately precedes the number and
            currency symbol.
   4        The sign string immediately succeeds the number and
            currency symbol.
 

3  Return_Value

   x                  Pointer to the lconv structure.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <limits.h>
       #include <locale.h>
       #include <string.h>

       /* The following test program will set up the British English   */
       /* locale, and then extract the International Currency symbol   */
       /* and the International Fractional Digits fields for this      */
       /* locale and print them.                                       */

       int main()
       {
           /* Declare variables                                        */

           char *return_val;
           struct lconv *lconv_ptr;

           /* Load a locale                                            */

           return_val = (char *) setlocale(LC_ALL, "en_GB.iso8859-1");

           /* Did the locale load successfully?                        */

           if (return_val == NULL) {

               /* It failed to load the locale                         */
              printf("ERROR : The locale is unknown");
               exit(EXIT_FAILURE);
           }

           /*  Get the lconv structure from the locale                 */

           lconv_ptr = (struct lconv *) localeconv();

           /* Compare the international currency symbol string with an */
           /* empty string. If they are equal, then the international  */
           /* currency symbol is not defined in the locale.            */

           if (strcmp(lconv_ptr->int_curr_symbol, "")) {
               printf("International Currency Symbol = %s\n",
                      lconv_ptr->int_curr_symbol);
           }
           else {
               printf("International Currency Symbol =");
               printf("[Not available in this locale]\n");
           }

           /* Compare International Fractional Digits with CHAR_MAX.   */
           /* If they are equal, then International Fractional Digits  */
           /* are not defined in this locale.                          */

           if ((unsigned char) (lconv_ptr->int_frac_digits) != CHAR_MAX) {
               printf("International Fractional Digits = %d\n",
                      lconv_ptr->int_frac_digits);
           }
           else {
               printf("International Fractional Digits =");
               printf("[Not available in this locale]\n");
           }
       }

     Running the example program produces the following result:

       International Currency Symbol = GBP
       International Fractional Digits = 2
 

2  localtime
   Convert a time value to broken-down local time.

   Format

     #include  <time.h>

     struct tm *localtime  (const time_t *timer);

     struct tm *localtime_r  (const time_t *timer, struct tm *result); 
                                  (ISO POSIX-1)
 

3  Function_Variants
   Compiling with the _DECC_V4_SOURCE and _VMS_V6_SOURCE feature-
   test macros defined enables a local-time-based entry point to the
   localtime_r function that is equivalent to the behavior before
   OpenVMS Version 7.0.
 

3  Arguments
 

timer

   A pointer to a time in seconds since the Epoch. You can generate
   this time by using the time function or you can supply a time.
 

result

   A pointer to a tm structure where the result is stored. The tm
   structure is defined in the <time.h> header file, and is also
   shown in tm Structure.
 

3  Description
   The localtime and localtime_r functions convert the time (in
   seconds since the Epoch) pointed to by timer into a broken-down
   time, expressed as a local time, and store it in a tm structure.

   The difference between the localtime_r and localtime functions
   is that the former stores the result into a user-specified tm
   structure. The latter stores the result into thread-specific
   static memory allocated by the Compaq C RTL, and which is
   overwritten by subsequent calls to localtime; you must make a
   copy if you want to save it.

   On success, localtime returns a pointer to the tm structure;
   localtime_r returns its second argument. On failure, these
   functions return the NULL pointer.

   The tm structure is defined in the <time.h> header file and
   described in tm Structure.

   Table REF-4 tm Structure

   int tm_sec;      Seconds after the minute (0-60)
   int tm_min;      Minutes after the hour (0-59)
   int tm_hour;     Hours since midnight (0-23)
   int tm_mday;     Day of the month (1-31)
   int tm_mon;      Months since January (1-11)
   int tm_year;     Years since 1900
   int tm_wday;     Days since Sunday (0-6)
   int tm_yday;     Days since January 1 (0-365)
   int tm_isdst;    Daylight Savings Time flag

                    o  tm_isdst = 0 for Standard Time

                    o  tm_isdst = 1 for Daylight Time

   long tm_gmtoff;  Seconds east of Greenwich (negative values
                    indicate seconds west of Greenwich)
   char *tm_zone;   Time zone string, for example "GMT"

   The type time_t is defined in the <time.h> header file as
   follows:

   typedef long int time_t

                                  NOTE

      Generally speaking, UTC-based time functions can affect in-
      memory time-zone information, which is processwide data.
      However, if the system time zone remains the same during
      the execution of the application (which is the common case)
      and the cache of timezone files is enabled (which is the
      default), then the _r variant of the time functions asctime_
      r, ctime_r, gmtime_r and localtime_r, is both thread-safe
      and AST-reentrant.

      If, however, the system time zone can change during the
      execution of the application or the cache of timezone files
      is not enabled, then both variants of the UTC-based time
      functions belong to the third class of functions, which are
      neither thread-safe nor AST-reentrant.
 

3  Return_Values

   x                  Pointer to a tm structure.
   NULL               Indicates failure.
 

2  log,log2,log10
   Return the logarithm of their arguments.

   Format

     #include  <math.h>

     double log  (double x);

     float logf  (float x); (Integrity servers, Alpha)

     long double logl  (long double x); (Integrity servers, Alpha)

     double log2  (double x); (Integrity servers, Alpha)

     float log2f  (float x); (Integrity servers, Alpha)

     long double log2l  (long double x); (Integrity servers, Alpha)

     double log10  (double x);

     float log10f  (float x); (Integrity servers, Alpha)

     long double log10l  (long double x);
                         (Integrity servers, Alpha)
 

3  Argument
 

x

   A real number.
 

3  Description
   The log functions compute the natural (base e) logarithm of x.

   The log2 functions compute the base 2 logarithm of x.

   The log10 functions compute the common (base 10) logarithm of x.
 

3  Return_Values

   x                  The logarithm of the argument (in the
                      appropriate base).
   -HUGE_VAL          x is 0 (errno is set to ERANGE), or x is
                      negative (errno is set to EDOM).
   NaN                x is NaN; errno is set to EDOM.
 

2  log1p
   Computes ln(1+y) accurately.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double log1p  (double y);

     float log1pf  (float y);

     long double log1pl  (long double y);
 

3  Argument
 

y

   A real number greater than -1.
 

3  Description
   The log1p functions compute ln(1+y) accurately, even for tiny y.
 

3  Return_Values

   x                  The natural logarithm of (1+y).
   -HUGE_VAL          y is less than -1 (errno is set to EDOM), or y
                      = -1 (errno is set to ERANGE).
   NaN                y is NaN; errno is set to EDOM.
 

2  logb
   Returns the radix-independent exponent of the argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double logb  (double x);

     float logbf  (float x);

     long double logbl  (long double x);
 

3  Argument
 

x

   A nonzero, real number.
 

3  Description
   The logb functions return the exponent of x, which is the
   integral part of log(2)|x|, as a signed floating-point value,
   for nonzero x.
 

3  Return_Values

   x                  The exponent of x.
   -HUGE_VAL          x = 0.0; errno is set to EDOM.
   +Infinity          x is +Infinity or -Infinity.
   NaN                y is NaN; errno is set to EDOM.
 

2  longjmp
   Provides a way to transfer control from a nested series of
   function invocations back to a predefined point without returning
   normally; that is, by not using a series of return statements.
   The longjmp function restores the context of the environment
   buffer.

   Format

     #include  <setjmp.h>

     void longjmp  (jmp_buf env, int value);
 

3  Arguments
 

env

   The environment buffer, which must be an array of integers long
   enough to hold the register context of the calling function.
   The type jmp_buf is defined in the <setjmp.h> header file. The
   contents of the general-purpose registers, including the program
   counter (PC), are stored in the buffer.
 

value

   Passed from longjmp to setjmp, and then becomes the subsequent
   return value of the setjmp call. If value is passed as 0, it is
   converted to 1.
 

3  Description
   When setjmp is first called, it returns the value 0. If longjmp
   is then called, naming the same environment as the call to
   setjmp, control is returned to the setjmp call as if it had
   returned normally a second time. The return value of setjmp in
   this second return is the value you supply in the longjmp call.
   To preserve the true value of setjmp, the function calling setjmp
   must not be called again until the associated longjmp is called.

   The setjmp function preserves the hardware general-purpose
   registers, and the longjmp function restores them. After a
   longjmp, all variables have their values as of the time of the
   longjmp except for local automatic variables not marked volatile.
   These variables have indeterminate values.

   The setjmp and longjmp functions rely on the OpenVMS condition-
   handling facility to effect a nonlocal goto with a signal
   handler. The longjmp function is implemented by generating a
   Compaq C RTL specified signal and allowing the OpenVMS condition-
   handling facility to unwind back to the desired destination.
   The Compaq C RTL must be in control of signal handling for any
   Compaq C image.

   For Compaq C to be in control of signal handling, you must
   establish all exception handlers through a call to the
   VAXC$ESTABLISH function (rather than LIB$ESTABLISH).

                                  NOTE

      The C RTL provides nonstandard decc$setjmp and decc$fast_
      longjmp functions for Alpha and Integrity server systems.
      To use these nonstandard functions instead of the standard
      ones, a program must be compiled with the __FAST_SETJMP or
      __UNIX_SETJMP macros defined.

      Unlike the standard longjmp function, the decc$fast_longjmp
      function does not convert its second argument from 0 to 1.
      After a call to decc$fast_longjmp, a corresponding setjmp
      function returns with the exact value of the second argument
      specified in the decc$fast_longjmp call.
 

3  Restrictions
   You cannot invoke the longjmp function from an OpenVMS condition
   handler. However, you may invoke longjmp from a signal handler
   that has been established for any signal supported by the
   Compaq C RTL, subject to the following nesting restrictions:

   o  The longjmp function will not work if invoked from nested
      signal handlers. The result of the longjmp function, when
      invoked from a signal handler that has been entered as a
      result of an exception generated in another signal handler,
      is undefined.

   o  Do not invoke the setjmp function from a signal handler unless
      the associated longjmp is to be issued before the handling of
      that signal is completed.

   o  Do not invoke the longjmp function from within an exit handler
      (established with atexit or SYS$DCLEXH). Exit handlers are
      invoked after image tear-down, so the destination address of
      the longjmp no longer exists.

   o  Invoking longjmp from within a signal handler to return to
      the main thread of execution might leave your program in
      an inconsistent state. Possible side effects include the
      inability to perform I/O or to receive any more UNIX signals.
 

2  longname
   Returns the full name of the terminal.

   Format

     #include  <curses.h>

     void longname  (char *termbuf, char *name);
 

3  Function_Variants
   The longname function has variants named _longname32 and 
   _longname64 for use with 32-bit and 64-bit pointer sizes,
   respectively.
 

3  Arguments
 

termbuf

   A string containing the name of the terminal.
 

name

   A character-string buffer with a minimum length of 64 characters.
 

3  Description
   The terminal name is in a readable format so that you can
   double-check to be sure that Curses has correctly identified
   your terminal. The dummy argument termbuf is required for UNIX
   software compatibility and serves no function in the OpenVMS
   environment. If portability is a concern, you must write a set
   of dummy routines to perform the functionality provided by the
   database termcap in the UNIX system environment.
 

2  lrand48
   Generates uniformly distributed pseudorandom-number sequences.
   Returns 48-bit signed long integers.

   Format

     #include  <stdlib.h>

     long int lrand48  (void);
 

3  Description
   The lrand48 function generates pseudorandom numbers using the
   linear congruential algorithm and 48-bit integer arithmetic.

   It returns nonnegative, long integers uniformly distributed over
   the range of y values such that 0 
   Before you call the lrand48 function use either srand48, seed48,
   or lcong48 to initialize the random-number generator. You must
   initialize prior to invoking the lrand48 function, because it
   stores the last 48-bit Xi generated into an internal buffer.
   (Although it is not recommended, constant default initializer
   values are supplied automatically if the drand48, lrand48,
   or mrand48 functions are called without first calling an
   initialization function.)

   The function works by generating a sequence of 48-bit integer
   values, Xi, according to the linear congruential formula:

          Xn+1 = (aXn+c)mod m        n >= 0

   The argument m equals 248, so 48-bit integer arithmetic is

   performed. Unless you invoke the lcong48 function, the multiplier
   value a and the addend value c are:

         a = 5DEECE66D16 = 2736731631558

         c = B16 = 138

   The value returned by the lrand48 function is computed by
   first generating the next 48-bit Xi in the sequence. Then the
   appropriate bits, according to the type of data item to be
   returned, are copied from the high-order (most significant) bits
   of Xi and transformed into the returned value.

   See also drand48, lcong48, mrand48, seed48, and srand48.
 

3  Return_Value

   n                  Signed nonnegative long integers uniformly
                      distributed over the range 0  

2  lrint
   Rounds to the nearest integer value, rounding according to the
   current rounding direction.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     long lrint  (double x);

     long lrintf  (float x);

     long lrintl  (long double x);
 

3  Argument
 

x

   A real value.
 

3  Description
   The lrint functions return the rounded integer value of x,
   rounded according to the current rounding direction.
 

3  Return_Values

   n                  Upon success, the rounded integer value.
 

2  lround
   Rounds to the nearest integer value, rounding halfway cases away
   from zero regardless of the current rounding direction.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     long lround  (double x);

     long lroundf  (float x);

     long lroundl  (long double x);
 

3  Argument
 

x

   A real value.
 

3  Description
   The lround functions return the rounded integer value of x, with
   halfway cases rounded away from zero regardless of the current
   rounding direction.
 

3  Return_Values

   n                  Upon success, the rounded integer value.
 

2  lseek
   Positions a file to an arbitrary byte position and returns the
   new position.

   Format

     #include  <unistd.h>

     off_t lseek  (int file_desc, off_t offset, int direction);
 

3  Arguments
 

file_desc

   An integer returned by open, creat, dup, or dup2.
 

offset

   The offset, specified in bytes. The off_t data type is either a
   32-bit or a 64-bit integer. The 64-bit interface allows for file
   sizes greater than 2 GB, and can be selected at compile time by
   defining the _LARGEFILE feature-test macro as follows:

   CC/DEFINE=_LARGEFILE
 

direction

   An integer indicating whether the offset is to be measured
   forward from the beginning of the file (direction=SEEK_SET),
   forward from the current position (direction=SEEK_CUR), or
   backward from the end of the file (direction=SEEK_END).
 

3  Description
   The lseek function can position a fixed-length record-access
   file with no carriage control or a stream-access file on any
   byte offset, but can position all other files only on record
   boundaries.

   The available Standard I/O functions position a record file at
   its first byte, at the end-of-file, or on a record boundary.
   Therefore, the arguments given to lseek must specify either
   the beginning or end of the file, a 0 offset from the current
   position (an arbitrary record boundary), or the position returned
   by a previous, valid lseek call.

   This function returns the new file position as an integer of type
   off_t which, like the offset argument, is either a 64-bit integer
   if _LARGEFILE is defined, or a 32-bit integer if not.

   For a portable way to position an arbitrary byte location with
   any type of file, see the fgetpos and fsetpos functions.

                                CAUTION

      If, while accessing a stream file, you seek beyond the
      end-of-file and then write to the file, the lseek function
      creates a hole by filling the skipped bytes with zeros.

      In general, for record files, lseek should only be directed
      to an absolute position that was returned by a previous
      valid call to lseek or to the beginning or end of a file.
      If a call to lseek does not satisfy these conditions, the
      results are unpredictable.

   See also open, creat, dup, dup2, and fseek.
 

3  Return_Values

   x                  The new file position.
   -1                 Indicates that the file descriptor is
                      undefined, or a seek was attempted before
                      the beginning of the file.
 

2  lstat
   Retrieves information about the specified file.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <sys/stat.h>

     int lstat  (const char *restrict file_path, struct stat
                *restrict user_buffer);
 

3  Arguments
 

file_path

   The name of the file for which you want to retrieve information.
 

user_buffer

   The stat structure in which information is returned.
 

3  Description
   The lstat function retrieves information about the specified file
   (file_path). If the file is a symbolic link, information about
   the link itself is returned (in contrast to stat, which returns
   information about the file that the symbolic link points to).

   See also symlink, unlink, readlink, realpath, and lchown.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. errno is set to any errno
                      value returned by stat.
 

2  lwait
   Waits for I/O on a specific file to complete.

   Format

     #include  <stdio.h>

     int lwait  (int fd);
 

3  Argument
 

fd

   A file descriptor corresponding to an open file.
 

3  Description
   The lwait function is used primarily to wait for completion of
   pending asynchronous I/O.
 

3  Return_Values

   0                  Indicates successful completion.
   -1                 Indicates an error.
 

2  malloc
   Allocates an area of memory. These functions are AST-reentrant.

   Format

     #include  <stdlib.h>

     void *malloc  (size_t size);
 

3  Function_Variants
   The malloc function has variants named _malloc32 and _malloc64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Argument
 

size

   The total number of bytes to be allocated.
 

3  Description
   The malloc function allocates a contiguous area of memory whose
   size, in bytes, is supplied as an argument. The space is not
   initialized.

                                  NOTE

      The malloc routines call the system routine LIB$VM_MALLOC.
      Because LIB$VM_MALLOC is designed as a general-purpose
      routine to allocate memory, it is called upon in a wide
      array of scenarios to allocate and reallocate blocks
      efficiently. The most common usage is the management of
      smaller blocks of memory, and the most important aspect of
      memory allocation under these circumstances is efficiency.

      LIB$VM_MALLOC makes use of its own free space to satisfy
      requests, once the heap storage is consumed by splitting
      large blocks and merging adjacent blocks. Memory can still
      become fragmented, leaving unused blocks. Once heap storage
      is consumed, LIB$VM_MALLOC manages its own free space and
      merged blocks to satisfy requests, but varying sizes of
      memory allocations can cause blocks to be left unused.

      Because LIB$VM_MALLOC cannot be made to satisfy all
      situations in the best possible manner, perform your own
      memory management if you have special memory usage needs.
      This assures the best use of memory for your particular
      application.

      The OpenVMS Programming Concepts Manual explains the several
      memory allocation routines that are available. They are
      grouped into three levels of hierarchy:

      1. At the highest level are the RTL Heap Management Routines
         LIB$GET_VM and LIB$FREE_VM, which provide a mechanism
         for allocating and freeing blocks of memory of arbitrary
         size. Also at this level are the routines based on the
         concept of zones, such as LIB$CREATE_VM_ZONE, and so on.

      2. At the next level are the RTL Page Management routines
         LIB$GET_VM_PAGE and LIB$FREE_VM_PAGE, which allocate a
         specified number of contiguous pages.

      3. At the lowest level are the Memory Management System
         Services, such as $CRETVA and $EXPREG, that provide
         extensive control over address space allocation. At this
         level, you must manage the allocation precisely.

   The maximum amount of memory allocated at once is limited to
   0xFFFFD000.
 

3  Return_Values

   x                  The address of the first byte, which
                      is aligned on a quadword boundary
                      (Alpha only) or an octaword boundary
                      (Integrity servers(ONLY)) .
   NULL               Indicates that the function is unable to
                      allocate enough memory. errno is set to
                      ENOMEM.
 

2  mblen
   Determines the number of bytes comprising a multibyte character.

   Format

     #include  <stdlib.h>

     int mblen  (const char *s, size_t n);
 

3  Arguments
 

s

   A pointer to the multibyte character.
 

n

   The maximum number of bytes that comprise the multibyte
   character.
 

3  Description
   If the character is n bytes or less, the mblen function returns
   the number of bytes comprising the multibyte character pointed
   to by s. If the character is greater than n bytes, the function
   returns -1 to indicate an error.

   This function is affected by the LC_CTYPE category of the
   program's current locale.
 

3  Return_Values

   x                  The number of bytes that comprise the
                      multibyte character, if the next n or fewer
                      bytes form a valid character.
   0                  If s is NULL or a pointer to the NULL
                      character.
   -1                 Indicates an error. The function sets errno to
                      EILSEQ - Invalid character detected.
 

2  mbrlen
   Determines the number of bytes comprising a multibyte character.

   Format

     #include  <wchar.h>

     size_t mbrlen  (const char *s, size_t n, mbstate_t *ps);
 

3  Arguments
 

s

   A pointer to a multibyte character.
 

n

   The maximum number of bytes that comprise the multibyte
   character.
 

ps

   A pointer to the mbstate_t object. If a NULL pointer is
   specified, the function uses its internal mbstate_t object.
   mbstate_t is an opaque datatype intended to keep the conversion
   state for the state-dependent codesets.
 

3  Description
   The mbrlen function is equivalent to the call:

       mbrtowc(NULL, s, n, ps != NULL ? ps : &internal)

   Where internal is the mbstate_t object for the mbrlen function.

   If the multibyte character pointed to by s is of n bytes or less,
   the function returns the number of bytes comprising the character
   (including any shift sequences).

   If either an encoding error occurs or the next n bytes contribute
   to an incomplete but potentially valid multibyte character, the
   function returns -1 or -2, respectively.

   See also mbrtowc.
 

3  Return_Values

   x                  The number of bytes comprising the multibyte
                      character.
   0                  Indicates that s is a NULL pointer or a
                      pointer to a null byte.
   -1                 Indicates an encoding error, in which case
                      the next n or fewer bytes do not contribute
                      to a complete and valid multibyte character.
                      errno is set to EILSEQ; the conversion state
                      is undefined.
   -2                 Indicates an incomplete but potentially valid
                      multibyte character (all n bytes have been
                      processed).
 

2  mbrtowc
   Converts a multibyte character to its wide-character
   representation.

   Format

     #include  <wchar.h>

     size_t mbrtowc  (wchar_t *pwc, const char *s, size_t n,
                     mbstate_t *ps);
 

3  Arguments
 

pwc

   A pointer to the resulting wide-character code.
 

s

   A pointer to a multibyte character.
 

n

   The maximum number of bytes that comprise the multibyte
   character.
 

ps

   A pointer to the mbstate_t object. If a NULL pointer is
   specified, the function uses its internal mbstate_t object.
   mbstate_t is an opaque datatype intended to keep the conversion
   state for the state-dependent codesets.
 

3  Description
   If s is a NULL pointer, mbrtowc is equivalent to the call:

       mbrtowc(NULL, "", 1, ps)

   In this case, the values of pwc and n are ignored.

   If s is not a NULL pointer, mbrtowc inspects at most n bytes
   beginning with the byte pointed to by s to determine the
   number of bytes needed to complete the next multibyte character
   (including any shift sequences).

   If the function determines that the next multibyte character
   is completed, it determines the value of the corresponding wide
   character and then, if pwc is not a NULL pointer, stores that
   value in the object pointed to by pwc. If the corresponding
   wide character is the null wide character, the resulting state
   described is the initial conversion state.

   If mbrtowc is called as a counting function, which means that pwc
   is a NULL pointer and s is neither a NULL pointer nor a pointer
   to a null byte, the value of the internal mbstate_t object will
   remain unchanged.
 

3  Return_Values

   x                  The number of bytes comprising the multibyte
                      character.
   0                  The next n or fewer bytes complete the
                      multibyte character that corresponds to the
                      null wide character (which is the value stored
                      if pwc is not a NULL pointer). The wide-
                      character code corresponding to a null byte
                      is zero.
   -1                 Indicates an encoding error. The next n or
                      fewer bytes do not contribute to a complete
                      and valid multibyte character. errno is set to
                      EILSEQ. The conversion state is undefined.
   -2                 Indicates an incomplete but potentially valid
                      multibyte character (all n bytes have been
                      processed).
 

2  mbstowcs
   Converts a sequence of multibyte characters into a sequence of
   corresponding wide-character codes.

   Format

     #include  <stdlib.h>

     size_t mbstowcs  (wchar_t *pwcs, const char *s, size_t n);
 

3  Arguments
 

pwcs

   A pointer to the array containing the resulting sequence of wide-
   character codes.
 

s

   A pointer to the array of multibyte characters.
 

n

   The maximum number of wide-character codes that can be stored in
   the array pointed to by pwcs.
 

3  Description
   The mbstowcs function converts a sequence of multibyte characters
   from the array pointed to by s to a sequence of wide-character
   codes that are stored into the array pointed to by pwcs, up to a
   maximum of n codes.

   This function is affected by the LC_CTYPE category of the
   program's current locale. If copying takes place between objects
   that overlap, the behavior is undefined.
 

3  Return_Values

   x                  The number of array elements modified or
                      required, not included any terminating zero
                      code. The array will not be zero-terminated
                      if the value returned is n. If pwcs is the
                      NULL pointer, mbstowcs returns the number
                      of elements required for the wide-character
                      array.
   (size_t) -1        Indicates that an error occurred. The function
                      sets errno to EILSEQ - Invalid character
                      detected.
 

2  mbtowc
   Converts a multibyte character to its wide-character equivalent.

   Format

     #include  <stdlib.h>

     int mbtowc  (wchar_t *pwc, const char *s, size_t n);
 

3  Arguments
 

pwc

   A pointer to the resulting wide-character code.
 

s

   A pointer to the multibyte character.
 

n

   The maximum number of bytes that comprise the next multibyte
   character.
 

3  Description
   If the character is n or fewer bytes, the mbtowc function
   converts the multibyte character pointed to by s to its wide-
   character equivalent. If the character is invalid or greater than
   n bytes, the function returns -1 to indicate an error.

   If pwc is a NULL pointer and s is not a null pointer, the
   function determines the number of bytes that constitute the
   multibyte character pointed to by s (regardless of the value
   of n).

   This function is affected by the LC_CTYPE category of the
   program's current locale.
 

3  Return_Values

   x                  The number of bytes that comprise the valid
                      character pointed to by s.
   0                  If s is either a NULL pointer or a pointer to
                      the null byte.
   -1                 Indicates an error. The function sets errno to
                      EILSEQ - Invalid character detected.
 

2  mbsinit
   Determines whether an mbstate_t object decribes an initial
   conversion state.

   Format

     #include  <wchar.h>

     int mbsinit  (const mbstate_t *ps);
 

3  Argument
 

ps

   A pointer to the mbstate_t object. mbstate_t is an opaque
   datatype intended to keep the conversion state for the state-
   dependent codesets.
 

3  Description
   If ps is not a NULL pointer, the mbsinit function determines
   whether the mbstate_t object pointed to by ps describes an
   initial conversion state. A zero mbstate_t object always
   describes an initial conversion state.
 

3  Return_Values

   nonzero            The ps argument is a NULL pointer, or the
                      mbstate_t object pointed to by ps describes an
                      initial conversion state.
   0                  The mbstate_t object pointed to by ps does not
                      describe an initial conversion state.
 

2  mbsrtowcs
   Converts a sequence of multibyte characters to a sequence of
   corresponding wide-character codes.

   Format

     #include  <wchar.h>

     size_t mbsrtowcs  (wchar_t *dst, const char **src, size_t len,
                       mbstate_t *ps);
 

3  Function_Variants
   The mbsrtowcs function has variants named _mbsrtowcs32 and
   _mbsrtowcs64 for use with 32-bit and 64-bit pointer sizes,
   respectively.
 

3  Arguments
 

dst

   A pointer to the destination array containing the resulting
   sequence of wide-character codes.
 

src

   An address of the pointer to an array containing a sequence of
   multibyte characters to be converted.
 

len

   The maximum number of wide character codes that can be stored in
   the array pointed to by dst.
 

ps

   A pointer to the mbstate_t object. If a NULL pointer is
   specified, the function uses its internal mbstate_t object.
   mbstate_t is an opaque datatype intended to keep the conversion
   state for the state-dependent codesets.
 

3  Description
   The mbsrtowcs function converts a sequence of multibyte
   characters, beginning in the conversion state described by the
   object pointed to by ps, from the array indirectly pointed to by
   src, into a sequence of corresponding wide characters.

   If dst is not a NULL pointer, the converted characters are stored
   into the array pointed to by dst. Conversion continues up to and
   including a terminating null character, which is also stored.

   Conversion stops earlier for one of the following reasons:

   o  A sequence of bytes is encountered that does not form a valid
      multibyte character.

   o  If dst is not a NULL pointer, when len codes have been stored
      into the array pointed to by dst.

   If dst is not a NULL pointer, the pointer object pointed to by
   src is assigned either a NULL pointer (if the conversion stopped
   because of reaching a terminating null wide character), or the
   address just beyond the last multibyte character converted (if
   any). If conversion stopped because of reaching a terminating
   null wide character, the resulting state described is the initial
   conversion state.
 

3  Return_Values

   n                  The number of multibyte characters
                      successfully converted, sequence, not
                      including the terminating null (if any).
   -1                 Indicates an error. A sequence of bytes that
                      do not form valid multibyte character was
                      encountered. errno is set to EILSEQ; the
                      conversion state is undefined.
 

2  memccpy
   Copies characters sequentially between strings in memory areas.

   Format

     #include  <string.h>

     void *memccpy  (void *dest, void *source, int c, size_t n);
 

3  Function_Variants
   The memccpy function has variants named _memccpy32 and _memccpy64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

dest

   A pointer to the location of a destination string.
 

source

   A pointer to the location of a source string.
 

c

   A character that you want to search for.
 

n

   The number of charcter you want to copy.
 

3  Description
   The memccpy function operates on strings in memory areas. A
   memory area is a group of contiguous characters bound by a count
   and not terminated by a null character. The function does not
   check for overflow of the receiving memory area. The memccpy
   function is defined in the <string.h> header file.

   The memccpy function sequentially copies characters from the
   location pointed to by source into the location pointed to by
   dest until one of the following occurs:

   o  The character specified by c (converted to an unsigned char)
      is copied.

   o  The number of characters specified by n is copied.
 

3  Return_Values

   x                  A pointer to the character following the
                      character specified by c in the string pointed
                      to by dest.
   NULL               Indicates an error. The character c is not
                      found after scanning n characters in the
                      string.
 

2  memchr
   Locates the first occurrence of the specified byte within the
   initial size bytes of a given object.

   Format

     #include  <string.h>

     void *memchr  (const void *s1, int c, size_t size);
 

3  Function_Variants
   The memchr function has variants named _memchr32 and _memchr64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

s1

   A pointer to the object to be searched.
 

c

   The byte value to be located.
 

size

   The length of the object to be searched.

   If size is zero, memchr returns NULL.
 

3  Description
   Unlike strchr, the memchr function does not stop when it
   encounters a null character.
 

3  Return_Values

   pointer            A pointer to the first occurrence of the byte.
   NULL               Indicates that the specified byte does not
                      occur in the object.
 

2  memcmp
   Compares two objects, byte by byte. The compare operation starts
   with the first byte in each object.

   Format

     #include  <string.h>

     int memcmp  (const void *s1, const void *s2, size_t size);
 

3  Arguments
 

s1

   A pointer to the first object.
 

s2

   A pointer to the second object.
 

size

   The length of the objects to be compared.

   If size is zero, the two objects are considered equal.
 

3  Description
   The memcmp function uses native byte comparison. The sign of
   the value returned is determined by the sign of the difference
   between the values of the first pair of unlike bytes in the
   objects being compared. Unlike the strcmp function, the memcmp
   function does not stop when a null character is encountered.
 

3  Return_Value

   x                  An integer less than, equal to, or greater
                      than 0, depending on whether the lexical value
                      of the first object is less than, equal to, or
                      greater than that of the second object.
 

2  memcpy
   Copies a specified number of bytes from one object to another.

   Format

     #include  <string.h>

     void *memcpy  (void *dest, const void *source, size_t size);
 

3  Function_Variants
   The memcpy function has variants named _memcpy32 and _memcpy64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

dest

   A pointer to the destination object.
 

source

   A pointer to the source object.
 

size

   The length of the object to be copied.
 

3  Description
   The memcpy function copies size bytes from the object pointed
   to by source to the object pointed to by dest; it does not check
   for the overflow of the receiving memory area (dest). Unlike the
   strcpy function, the memcpy function does not stop when a null
   character is encountered.
 

3  Return_Value

   x                  The value of dest.
 

2  memmove
   Copies a specified number of bytes from one object to another.

   Format

     #include  <string.h>

     void *memmove  (void *dest, const void *source, size_t size);
 

3  Function_Variants
   The memmove function has variants named _memmove32 and _memmove64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

dest

   A pointer to the destination object.
 

source

   A pointer to the source object.
 

size

   The length of the object to be copied.
 

3  Description
   In Compaq C for OpenVMS Systems, memmove and memcpy perform the
   same function. Programs that require portability should use
   memmove if the area pointed at by dest could overlap the area
   pointed at by source.
 

3  Return_Value

   x                  The value of dest.
 

3  Example

       #include <string.h>
       #include <stdio.h>

       main()
       {
          char pdest[14] = "hello   there";
          char *psource = "you are there";

          memmove(pdest, psource, 7);
          printf("%s\n", pdest);
       }

     This example produces the following output:

       you are there
 

2  memset
   Sets a specified number of bytes in a given object to a given
   value.

   Format

     #include  <string.h>

     void *memset  (void *s, int value, size_t size);
 

3  Function_Variants
   The memset function has variants named _memset32 and _memset64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

s

   An array pointer.
 

value

   The value to be placed in s.
 

size

   The number of bytes to be placed in s.
 

3  Description
   The memset function copies value (converted to an unsigned char)
   into each of the first size characters of the object pointed to
   by s.

   This function returns s. It does not check for the overflow of
   the receiving memory area pointed to by s.
 

3  Return_Value

   x                  The value of s.
 

2  mkdir
   Creates a directory.

   Format

     #include  <stat.h>

     int mkdir  (const char *dir_spec, mode_t mode); (ISO POSIX-1)

     int mkdir  (const char *dir_spec, mode_t mode, . . . ); 
                (DEC C Extension)
 

3  Arguments
 

dir_spec

   A valid OpenVMS or UNIX style directory specification that may
   contain a device name. For example:

   DBA0:[BAY.WINDOWS]     /*    OpenVMS      */
   /dba0/bay/windows      /*   UNIX style    */

   This specification cannot contain a node name, filename, file
   extension, file version, or a wildcard character. The same
   restriction applies to the UNIX style directory specifications.
 

mode

   A file protection. See the chmod function in this section for
   information about the specific file protections.

   The file protection of the new directory is derived from the
   mode argument, the process's file protection mask (see the umask
   function), and the parent-directory default protections.

   In a manner consistent with the OpenVMS behavior for creating
   directories, mkdir never applies delete access to the directory.
   An application that needs to set delete access should use an
   explicit call to chmod to set write permission.

   See the Description section of this function for more information
   about how the file protection is set for the newly created
   directory.
 

 . . .

   Represents the following optional arguments. These arguments have
   fixed position in the argument list, and cannot be arbitrarily
   placed.

      unsigned int uic
      The user identification code (UIC) that identifies the
      owner of the created directory. If this argument is 0, the
      Compaq C RTL gives the created directory the UIC of the parent
      directory. If this argument is not specified, the Compaq C RTL
      gives the created directory your UIC. This optional argument
      is specific to the Compaq C RTL and is not portable.

      unsigned short max_versions
      The maximum number of file versions to be retained in the
      created directory. The system automatically purges the
      directory keeping, at most, max_versions number of every file.

      If this argument is 0, the Compaq C RTL does not place a limit
      on the maximum number of file versions.

      If this argument is not specified, the Compaq C RTL gives
      the created directory the default version limit of the parent
      directory.

      This optional argument is specific to the Compaq C RTL and is
      not portable.

      unsigned short r_v_number
      The volume (device) on which to place the created directory
      if the device is part of a volume set. If this argument is
      not specified, the Compaq C RTL arbitrarily places the created
      directory within the volume set. This optional argument is
      specific to the Compaq C RTL and is not portable.
 

3  Description
   If dir_spec specifies a path that includes directories, which
   do not exist, intermediate directories are also created.
   This differs from the behavior of the UNIX system where these
   intermediate directories must exist and will not be created.

   If you do not specify any optional arguments, the Compaq C RTL
   gives the directory your UIC and the default version limit of the
   parent directory, and arbitrarily places the directory within the
   volume set. You cannot get the default behavior for the uic or
   max_versions arguments if you specify any arguments after them.

                                  NOTE

      The way to create files with OpenVMS RMS default protections
      using the UNIX system-call functions umask, mkdir, creat,
      and open is to call mkdir, creat, and open with a file-
      protection mode argument of 0777 in a program that never
      specifically calls umask. These default protections include
      correctly establishing protections based on ACLs, previous
      versions of files, and so on.

      In programs that do vfork/exec calls, the new process image
      inherits whether umask has ever been called or not from
      the calling process image. The umask setting and whether
      the umask function has ever been called are both inherited
      attributes.

   The file protection supplied by the mode argument is modified by
   the process's file protection mask in such a way that the file
   protection for the new directory is set to the bitwise AND of the
   mode argument and the complement of the file protection mask.

   Default file protections are supplied to the new directory
   from the parent-directory such that if a protection value bit
   in the new directory is zero, then the value of this bit is
   inherited from the parent directory. However, bits in the parent
   directory's file protection that indicate delete access do not
   cause corresponding bits to be set in the new directory's file
   protection.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates failure.
 

3  Examples

   1.umask (0002); /* turn world write access off */

     mkdir ("sys$disk:[.parentdir.childdir]", 0222); 
                                /* turn write access on */

     Parent directory file protection: System:RWD, Owner:RWD,
                                          Group:R, World:R

     The file protection derived from the combination of the mode
     argument and the file protection mask set by umask is (0222)
     & ~(0002), which is 0220. When the parent directory defaults
     are applied to this protection, the protection for the new
     directory becomes:

       File protection:    System:RWD, Owner:RWD, Group:RWD, World:R

   2.umask (0000);

     mkdir ("sys$disk:[.parentdir.childdir]", 0444);  
                                /* turn read access on */

     Parent directory file protection: System:RWD, Owner:RWD,
                                         Group:RWD, World:RWD

     The file protection derived from the combination of the mode
     argument and the file protection mask set by umask is (0444)
     & ~(0000), which is 0444. When the parent directory defaults
     are applied to this protection, the protection for the new
     directory is:

       File protection:    System:RW, Owner:RW, Group:RW, World:RW

     Note that delete access is not inherited.
 

2  mkstemp
   Constructs a unique filename.

   Format

     #include  <stdlib.h>

     int mkstemp  (char *template);
 

3  Argument
 

template

   A pointer to a string that is replaced with a unique filename.
   The string in the template argument must be a filename with six
   trailing Xs.
 

3  Description
   The mkstemp function replaces the six trailing Xs of the string
   pointed to by template with a unique set of characters, and
   returns a file descriptor for the file open for reading and
   writing.

   The string pointed to by template should look like a filename
   with six trailing X's. The mkstemp function replaces each X with
   a character from the portable file-name character set, making
   sure not to duplicate an existing filename.

   If the string pointed to by template does not contain six
   trailing Xs, -1 is returned.
 

3  Return_Values

   x                  An open file descriptor.
   -1                 Indicates an error. (The string pointed to by
                      template does not contain six trailing Xs.)
 

2  mktemp
   Creates a unique filename from a template.

   Format

     #include  <stdlib.h>

     char *mktemp  (char *template);
 

3  Function_Variants
   The mktemp function has variants named _mktemp32 and _mktemp64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Argument
 

template

   A pointer to a buffer containing a user-defined template. You
   supply the template in the form, namXXXXXX. The six trailing Xs
   are replaced by a unique series of characters. You may supply
   the first three characters. Because the template argument is
   overwritten, do not specify a string literal (const object).
 

3  Description
   The use of mktemp is not recommended for new applications. See
   the tmpnam and mkstemp functions for the preferable alternatives.
 

3  Return_Value

   x                  A pointer to the template, with the template
                      modified to contain the created filename. If
                      this value is a pointer to a null string, it
                      indicates that a unique filename cannot be
                      created.
 

2  mktime
   Converts a local-time structure to a time, in seconds, since the
   Epoch.

   Format

     #include  <time.h>

     time_t mktime  (struct tm *timeptr);
 

3  Function_Variants
   Compiling with the _DECC_V4_SOURCE and _VMS_V6_SOURCE feature-
   test macros defined enables a local-time-based entry point to the
   mktime function that is equivalent to the behavior before OpenVMS
   Version 7.0.
 

3  Argument
 

timeptr

   A pointer to the local-time structure.
 

3  Description
   The mktime function converts a local-time structure (struct tm)
   pointed to by timeptr, to a time in seconds since the Epoch (a
   time_t variable), in the same manner as the values returned by
   the time function.

   The original values of the tm_wday and tm_yday components of
   the structure are ignored, and the original values of the other
   components are not restricted to the ranges defined in <time.h>.
   Upon successful completion, the tm_wday and tm_yday components of
   the structure are set appropriately, and the other components are
   set to represent the specified time, with their values forced to
   the normal range.

   If the local time cannot be encoded, then mktime returns the
   value (time_t)(-1).

   The time_t type is defined in the <time.h> header file as
   follows:

   typedef unsigned long int time_t;

   Local time-zone information is set as if mktime called tzset.

   If the tm_isdst field in the local-time structure pointed to
   by timeptr is positive, mktime initially presumes that Daylight
   Savings Time (DST) is in effect for the specified time.

   If tm_isdst is 0, mktime initially presumes that DST is not in
   effect.

   If tm_isdst is negative, mktime attempts to determine whether or
   not DST is in effect for the specified time.
 

3  Return_Values

   x                  The specified calendar time encoded as a value
                      of type time_t.
   (time_t)(-1)       If the local time cannot be encoded.

                      Be aware that a return value of (time_t)(-1)
                      can also represent the valid date: Sun Feb 7
                      06:28:15 2106.
 

2  mmap
   Maps file system object into virtual memory. This function is
   reentrant.

   Format

     #include  <types.h>

     #include  <mman.h>

     void mmap  (void *addr, size_t len, int prot, int flags, int   
                filedes, off_t off); (X/Open, POSIX-1)

     void mmap  (void *addr, size_t len, int prot, int flags, int   
                filedes, off_t off ...); (DEC C Extension)
 

3  Function_Variants
   The mmap function has variants named _mmap32 and _mmap64 for use
   with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

addr

   The starting address of the new region (must be the page
   boundary).
 

len

   The length, in bytes, of the new region.
 

prot

   Access permission, as defined in the <mman.h> header file.
   Specify either PROT_NONE, PROT_READ, or PROT_WRITE.
 

flags

   Attributes of the mapped region as the results of a bitwise-
   inclusive OR operation on any combination of the following:

   o  MAP_FILE or MAP_ANONYMOUS

   o  MAP_VARIABLE or MAP_FIXED

   o  MAP_SHARED or MAP_PRIVATE
 

filedes

   The file that you want to map to the new mapped file region
   returned by the open function.
 

off

   The offset, specified in bytes. The off_t data type is either a
   64-bit or 32-bit integer. The 64-bit interface allows for file
   sizes greater than 2 GB, and can be selected at compile time by
   defining the _LARGEFILE feature-test macro as follows:

   CC/DEFINE=_LARGEFILE
 

 . . .

   An optional integer specifying additional flags for the
   SYS$CRMPSC system service for MAP_SHARED. This optional argument
   (Compaq C Extension) of the mmap function was introduced in
   OpenVMS Version 7.2.
 

3  Description
   The mmap function creates a new mapped file region, a new private
   region, or a new shared memory region.

   Your application must ensure correct synchronization when using
   mmap in conjunction with any other file access method, such as
   read and write, and standard input/output.

   Before calling mmap, the calling application must also ensure
   that all bytes in the range [off, off+len] are written to the
   file (using the fsync function, for example). If this requirement
   is not met, mmap fails with errno set to ENXIO (No such device or
   address).

   The addr and len arguments specify the requested starting address
   and length, in bytes, for the new region. The address is a
   multiple of the page size returned by sysconf(_SC_PAGE_SIZE).

   If the len argument is not a multiple of the page size returned
   by sysconf(_SC_PAGE_SIZE), then the result of any reference to
   an address between the end of the region and the end of the page
   containing the end of the region is undefined.

   The flags argument specifies attributes of the mapped region.
   Values for flags are constructed by a bitwise-inclusive OR
   operation on the flags from the following list of symbolic names
   defined in the <mman.h> header file:

   MAP_FILE         Create a mapped file region.
   MAP_ANONYMOUS    Create an unnamed memory region.
   MAP_VARIABLE     Place region at the computed address.
   MAP_FIXED        Place region at fixed address.
   MAP_SHARED       Share changes.
   MAP_PRIVATE      Changes are private.

   The MAP_FILE and MAP_ANONYMOUS flags control whether the region
   you want to map is a mapped file region or an anonymous shared
   memory region. One of these flags must be selected.

   If MAP_FILE is set in the flags argument:

   o  A new mapped file region is created, mapping the file
      associated with the filedes argument.

   o  The off argument specifies the file byte offset where the
      mapping starts. This offset must be a multiple of the page
      size returned by sysconf(_SC_PAGE_SIZE).

   o  If the end of the mapped file region is beyond the end of the
      file, the result of any reference to an address in the mapped
      file region corresponding to an offset beyond the end of the
      file is unspecified.

   If MAP_ANONYMOUS is set in the flags argument:

   o  A new memory region is created and initialized to all zeros.

   o  The filedes argument is ignored.


   The new region is placed at the requested address if the
   requested address is not null and it is possible to place the
   region at this address. When the requested address is null or
   the region cannot be placed at the requested address, the MAP_
   VARIABLE and MAP_FIXED flags control the placement of the region.
   One of these flags must be selected.

   If MAP_VARIABLE is set in the flags argument:

   o  If the requested address is null or if it is not possible for
      the system to place the region at the requested address, the
      region is placed at an address selected by the system.

   If MAP_FIXED is set in the flags argument:

   o  If the requested address is not null, the mmap function
      succeeds even if the requested address is already part of
      another region. (If the address is within an existing region,
      the effect on the pages within that region and within the area
      of the overlap produced by the two regions is the same as if
      they were unmapped. In other words, whatever is mapped between
      addr and addr + len is unmapped.)

   o  If the requested address is null and MAP_FIXED is specified,
      the results are undefined.

   The MAP_PRIVATE and MAP_SHARED flags control the visibility of
   modifications to the mapped file or shared memory region. One of
   these flags must be selected.

   If MAP_SHARED is set in the flags argument:

   o  If the region is a mapped region, modifications to the region
      are visible to other processes that mapped the same region
      using MAP_SHARED.

   o  If the region is a mapped file region, modifications to the
      region are written to the file. (Note that the modifications
      are not immediately written to the file because of buffer
      cache delay; that is, the write to the file does not occur
      until there is a need to reuse the buffer cache. If the
      modifications must be written to the file immediately, use
      the msync function to ensure that this is done.)

   If MAP_PRIVATE is set in the flags argument:

   o  Modifications to the mapped region by the calling process are
      not visible to other processes that mapped the same region
      using either MAP_PRIVATE or MAP_SHARED.

   o  Modifications to the mapped region by the calling process are
      not written to the file.

   It is unspecified whether modifications by processes that mapped
   the region using MAP_SHARED are visible to other processes that
   mapped the same region using MAP_PRIVATE.

   The prot argument specifies access permissions for the mapped
   region. Specify one of the following:

   PROT_NONE      No access
   PROT_READ      Read-only
   PROT_WRITE     Read/Write access

   After the successful completion of the mmap function, you can
   close the filedes argument without effect on the mapped region or
   on the contents of the mapped file. Each mapped region creates a
   file reference, similar to an open file descriptor, that prevents
   the file data from being deallocated.

                                  NOTE

      The following rules apply to OpenVMS specific file
      references:

      o  Because of the additional file reference, if filedes is
         not opened for file sharing, mmap reopens it with file
         sharing enabled.

      o  The additional file reference that remains for mapped
         regions implies that a later open, fopen, or create call
         to the file that is mapped must specify file sharing.

   Modifications made to the file using the write function are
   visible to mapped regions, and modifications to a mapped region
   are visible with the read function.

                                  NOTE

      Beginning with OpenVMS Version 7.2, while processing a MAP_
      SHARED request, the mmap function constructs the flags
      argument of the SYS$CRMPSC service as a bitwise inclusive
      OR of those bits it sets by itself to fulfill the MAP_
      SHARED request and those bits specified by the caller in
      the optional argument.

      By default, for MAP_SHARED the mmap function creates a
      temporary group global section. The optional mmap argument
      provides the caller with direct access to the features of
      the SYS$CRMPSC system service.

      Using the optional argument, the caller can create, for
      example, a system global section (SEC$M_SYSGBL bit) or
      permanent global section (SEC$M_PERM bit). For example,
      to create a system permanent global section, the caller
      can specify (SEC$M_SYSGBL | SEC$M_PERM) in the optional
      argument.

      The mmap function does not check or set any privileges.
      It is the responsibility of the caller to set appropriate
      privileges, such as SYSGBL privilege for SEC$M_SYSGBL, and
      PRMGBL for SEC$M_PERM, before calling mmap with the optional
      argument.

   See also read, write, open, fopen, creat, and sysconf.
 

3  Return_Values

   x                  The address where the mapping is placed.
   MAP_FAILED         Indicates an error; errno is set to one of the
                      following values:

                      o  EACCES - The file referred to by filedes
                         is not open for read access, or the file
                         is not open for write access and PROT_WRITE
                         was set for a MAP_SHARED mapping operation.

                      o  EBADF - The filedes argument is not a valid
                         file descriptor.

                      o  EINVAL -The flags or prot argument is
                         invalid, or the addr argument or off
                         argument is not a multiple of the page
                         size returned by sysconf(_SC_PAGE_SIZE).

                      o  ENODEV - The file descriptor filedes refers
                         to an object that cannot be mapped, such as
                         a terminal.

                      o  ENOMEM - There is not enough address space
                         to map len bytes.

                      o  ENXIO - The addresses specified by the
                         range [off, off + len] are invalid for
                         filedes.

                      o  EFAULT - The addr argument is an invalid
                         address.
 

2  modf
   Decomposes a floating-point number.

   Format

     #include  <math.h>

     double modf  (double x, double *iptr);

     float modff  (float x, float *iptr);                           
                  (Integrity servers, Alpha)

     long double modfl  (long double x, long double *iptr);         
                        (Integrity servers, Alpha)
 

3  Arguments
 

x

   An object of type double, float, or long double.
 

iptr

   A pointer to an object of type double, float, or long double to
   match the type of x.
 

3  Description
   The modf functions decompose their first argument x into a
   positive fractional part f and an integer part i, each of which
   has the same sign as x.

   The functions return f and assign i to the object pointed to by
   the second argument (iptr).
 

3  Return_Values

   x                  The fractional part of the argument x.
   NaN                x is NaN; errno is set to EDOM and *iptr is
                      set to NaN.
   0                  Underflow occurred; errno is set to ERANGE.
 

2  [w]move
   Change the current cursor position on the specified window to the
   coordinates (y,x). The move function acts on the stdscr window.

   Format

     #include  <curses.h>

     int move  (int y, int x);

     int wmove  (WINDOW *win, int y, int x);
 

3  Arguments
 

win

   A pointer to the window.
 

y

   A window coordinate.
 

x

   A window coordinate.
 

3  Description
   For more information, see the scrollok function in this section.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function makes the screen
                      scroll illegally.
 

2  mprotect
   Modifies access protections of memory mapping. This function is
   reentrant.

   Format

     #include  <mman.h>

     int mprotect  (void *addr, size_t len, int prot);
 

3  Arguments
 

addr

   The address of the region that you want to modify.
 

len

   The length, in bytes, of the region that you want to modify.
 

prot

   Access permission, as defined in the <mman.h> header file.
   Specify either PROT_NONE, PROT_READ, or PROT_WRITE.
 

3  Description
   The mprotect function modifies the access protection of a mapped
   file or shared memory region.

   The addr and len arguments specify the address and length, in
   bytes, of the region that you want to modify. The len argument
   must be a multiple of the page size as returned by sysconf(_SC_
   PAGE_SIZE). If len is not a multiple of the page size as returned
   by sysconf(_SC_PAGE_SIZE), the length of the region is rounded up
   to the next multiple of the page size.

   The prot argument specifies access permissions for the mapped
   region. Specify one of the following:

   PROT_NONE      No access
   PROT_READ      Read-only
   PROT_WRITE     Read/Write access

   The mprotect function does not modify the access permission of
   any region that lies outside of the specified region, except that
   the effect on addresses between the end of the region, and the
   end of the page containing the end of the region, is unspecified.

   If the mprotect function fails under a condition other than that
   specified by EINVAL, the access protection of some of the pages
   in the range [addr, addr + len] can change. Suppose the error
   occurs on some page at an addr2; mprotect can modify protections
   of all whole pages in the range [addr, addr2].

   See also sysconf.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to one of the
                      following values:

                      o  EACCESS - The prot argument specifies a
                         protection that conflicts with the access
                         permission set for the underlying file.

                      o  EINVAL - The prot argument is invalid, or
                         the addr argument is not a multiple of the
                         page size as returned by sysconf(_SC_PAGE_
                         SIZE).

                      o  EFAULT - The range [addr, addr + len]
                         includes an invalid address.
 

2  mrand48
   Generates uniformly distributed pseudorandom-number sequences.
   Returns 48-bit signed long integers.

   Format

     #include  <stdlib.h>

     long int mrand48  (void);
 

3  Description
   The mrand48 function generates pseudorandom numbers using the
   linear congruential algorithm and 48-bit integer arithmetic.

   It returns signed long integers uniformly distributed over the
   range of y values such that -231 
   Before you call the mrand48 function, use either srand48,
   seed48, or lcong48 to initialize the random-number generator.
   You must initialize the mrand48 function prior to invoking it,
   because it stores the last 48-bit Xi generated into an internal
   buffer. (Although it is not recommended, constant default
   initializer values are supplied automatically if the drand48,
   lrand48, or mrand48 functions are called without first calling an
   initialization function.)

   The function works by generating a sequence of 48-bit integer
   values, Xi, according to the linear congruential formula:

          Xn+1 = (aXn+c)mod m        n >= 0

   The argument m equals 248, so 48-bit integer arithmetic is

   performed. Unless you invoke the lcong48 function, the multiplier
   value a and the addend value c are:

         a = 5DEECE66D16 = 2736731631558

         c = B16 = 138

   The values returned by the mrand48 function is computed by
   first generating the next 48-bit Xi in the sequence. Then the
   appropriate bits, according to the type of returned data item,
   are copied from the high-order (most significant) bits of Xi and
   transformed into the returned value.

   See also drand48, lrand48, lcong48, seed48, and srand48.
 

3  Return_Value

   n                  Returns signed long integers uniformly
                      distributed over the range -231  

2  msync
   Synchronizes a mapped file.

   Format

     #include  <mman.h>

     int msync  (void *addr, size_t len, int flags);
 

3  Arguments
 

addr

   The address of the region that you want to synchronize.
 

len

   The length, in bytes, of the region that you want to synchronize.
 

flags

   One of the following symbolic constants defined in the <mman.h>
   header file:

   MS_SYNC        Synchronous cache flush
   MS_ASYNC       Asynchronous cache flush
   MS_            Invalidate cashed pages
   INVALIDATE
 

3  Description
   The msync function controls the caching operations of a mapped
   file region. Use msync to:

   o  Ensure that modified pages in the region transfer to the
      underlying storage device of the file.

   o  Control the visibility of modifications with respect to file
      system operations.

   The addr and len arguments specify the region to be synchronized.
   The len argument must be a multiple of the page size as returned
   by sysconf(_SC_PAGE_SIZE); otherwise, the length of the region is
   rounded up to the next multiple of the page size.

   If the flags argument is set to:

   flags Argument   Then the msync Function...

   MS_SYNC          Does not return until the system completes all
                    I/O operations.
   MS_ASYNC         Returns after the system schedules all I/O
                    operations.
   MS_INVALIDATE    Invalidates all cached copies of the pages. The
                    operating system must obtain new copies of the
                    pages from the file system the next time the
                    application references them.

   After a successful call to the msync function with the flags
   argument set to:

   o  MS_SYNC - All previous modifications to the mapped region
      are visible to processes using the read argument. Previous
      modifications to the file using the write function are lost.

   o  MS_INVALIDATE - All previous modifications to the file using
      the write function are visible to the mapped region. Previous
      direct modifications to the mapped region are lost.

   See also read, write, and sysconf.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to one of the
                      following values:

                      o  EIO - An I/O error occurred while reading
                         from or writing to the file system.

                      o  ENOMEM - The range specified by
                         [addr, addr + len] is invalid for a
                         process's address space, or the range
                         specifies one or more unmapped pages.

                      o  EINVAL - The addr argument is not a
                         multiple of the page size as returned by
                         sysconf(_SC_PAGE_SIZE).

                      o  EFAULT - The range [addr, addr + len]
                         includes an invalid address.
 

2  munmap
   Unmaps a mapped region. This function is reentrant.

   Format

     #include  <mman.h>

     int munmap  (void *addr, size_t len);
 

3  Arguments
 

addr

   The address of the region that you want to unmap.
 

len

   The length, in bytes, of that region the you want to unmap.
 

3  Description
   The munmap function unmaps a mapped file or shared memory region.

   The addr and len arguments specify the address and length, in
   bytes, respectively, of the region to be unmapped.

   The len argument must be a multiple of the page size as returned
   by sysconf(_SC_PAGE_SIZE); otherwise, the length of the region is
   rounded up to the next multiple of the page size.

   The result of using an address that lies in an unmapped region
   and not in any subsequently mapped region is undefined.

   See also sysconf.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to one of the
                      following values:

                      o  ENIVAL - The addr argument is not a
                         multiple of the page size as returned by
                         sysconf(_SC_PAGE_SIZE).

                      o  EFAULT - The range [addr, addr + len]
                         includes an invalid address.
 

2  mv[w]addch
   Move the cursor to coordinates (y,x) and add a character to the
   specified window.

   Format

     #include  <curses.h>

     int mvaddch  (int y, int x, char ch);

     int mvwaddch  (WINDOW *win, int y, int x, char ch);
 

3  Arguments
 

win

   A pointer to the window.
 

y

   A window coordinate.
 

x

   A window coordinate.
 

ch

   If this argument is a new-line character (\n), the mvaddch and
   mvwaddch functions clear the line to the end, and move the cursor
   to the next line at the same x coordinate. A carriage return (\r)
   moves the cursor to the beginning of the specified line. A tab
   (\t) moves the cursor to the next tabstop within the window.
 

3  Description
   This routine performs the same function as mvwaddch, but on the
   stdscr window.

   When mvwaddch is used on a subwindow, it writes the character
   onto the underlying window as well.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that writing the character would
                      cause the screen to scroll illegally. For more
                      information, see the scrollok function.
 

2  mv[w]addstr
   Move the cursor to coordinates (y,x) and add the specified
   string, to which str points, to the specified window.

   Format

     #include  <curses.h>

     int mvaddstr  (int y, int x, char *str);

     int mvwaddstr  (WINDOW *win, int y, int x, char *str);
 

3  Arguments
 

win

   A pointer to the window.
 

y

   A window coordinate.
 

x

   A window coordinate.
 

str

   A pointer to the character string.
 

3  Description
   This routine performs the same function as mvwaddstr, but on the
   stdscr window.

   When mvwaddstr is used on a subwindow, the string is written onto
   the underlying window as well.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function causes the screen
                      to scroll illegally, but it places as much of
                      the string onto the window as possible. For
                      more information, see the scrollok function.
 

2  mvcur
   Moves the terminal's cursor from (lasty,lastx) to (newy,newx).

   Format

     #include  <curses.h>

     int mvcur  (int lasty, int lastx, int newy, int newx);
 

3  Arguments
 

lasty

   The cursor position.
 

lastx

   The cursor position.
 

newy

   The resulting cursor position.
 

newx

   The resulting cursor position.
 

3  Description
   In Compaq C for OpenVMS Systems, mvcur and move perform the same
   function.

   See also move.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that moving the window placed part
                      or all of the window off the edge of the
                      terminal screen. The terminal screen remains
                      unaltered.
 

2  mv[w]delch
   Move the cursor to coordinates (y,x) and delete the character
   on the specified window. The mvdelch function acts on the stdscr
   window.

   Format

     #include  <curses.h>

     int mvdelch  (int y, int x);

     int mvwdelch  (WINDOW *win, int y, int x);
 

3  Arguments
 

win

   A pointer to the window.
 

y

   A window coordinate.
 

x

   A window coordinate.
 

3  Description
   Each of the following characters on the same line shifts to the
   left, and the last character becomes blank.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that deleting the character would
                      cause the screen to scroll illegally. For more
                      information, see the scrollok function.
 

2  mv[w]getch
   Move the cursor to coordinates (y,x), get a character from the
   terminal screen, and echo it on the specified window. The mvgetch
   function acts on the stdscr window.

   Format

     #include  <curses.h>

     int mvgetch  (int y, int x);

     int mvwgetch  (WINDOW *win, int y, int x);
 

3  Arguments
 

win

   A pointer to the window.
 

y

   A window coordinate.
 

x

   A window coordinate.
 

3  Description
   The mvgetch and mvwgetch functions refresh the specified window
   before fetching the character.
 

3  Return_Values

   x                  The returned character.
   ERR                Indicates that the function causes the screen
                      to scroll illegally. For more information, see
                      the scrollok function in this section.
 

2  mv[w]getstr
   Move the cursor to coordinates (y,x), get a string from the
   terminal screen, store it in the variable str (which must be
   large enough to contain the string), and echo it on the specified
   window. The mvgetstr function acts on the stdscr window.

   Format

     #include  <curses.h>

     int mvgetstr  (int y, int x, char *str);

     int mvwgetstr  (WINDOW *win, int y, int x, char *str);
 

3  Arguments
 

win

   A pointer to the window.
 

y

   A window coordinate.
 

x

   A window coordinate.
 

str

   The string that is displayed.
 

3  Description
   The mvgetstr and mvwgetstr functions strip the new-line
   terminator (\n) from the string.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function causes the screen
                      to scroll illegally.
 

2  mv[w]inch
   Move the cursor to coordinates (y,x) and return the character on
   the specified window without making changes to the window. The
   mvinch function acts on the stdscr window.

   Format

     #include  <curses.h>

     int mvinch  (int y, int x);

     int mvwinch  (WINDOW *win, int y, int x);
 

3  Arguments
 

win

   A pointer to the window.
 

y

   A window coordinate.
 

x

   A window coordinate.
 

3  Return_Values

   x                  The returned character.
   ERR                Indicates an input error.
 

2  mv[w]insch
   Move the cursor to coordinates (y,x) and insert the character
   ch into the specified window. The mvinsch function acts on the
   stdscr window.

   Format

     #include  <curses.h>

     int mvinsch  (int y, int x, char ch);

     int mvwinsch  (WINDOW *win, int y, int x, char ch);
 

3  Arguments
 

win

   A pointer to the window.
 

y

   A window coordinate.
 

x

   A window coordinate.
 

ch

   The character to be inserted at the window's coordinates.
 

3  Description
   After the character is inserted, each character on the line
   shifts to the right, and the last character on the line is
   deleted.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function makes the screen
                      scroll illegally. For more information, see
                      the scrollok function in this section.
 

2  mv[w]insstr
   Move the cursor to coordinates (y,x) and insert the specified
   string into the specified window. The mvinsstr function acts on
   the stdscr window.

   Format

     #include  <curses.h>

     int mvinsstr  (int y, int x, char *str);

     int mvwinsstr  (WINDOW *win, int y, int x, char *str);
 

3  Arguments
 

win

   A pointer to the window.
 

y

   A window coordinate.
 

x

   A window coordinate.
 

str

   The string that is displayed.
 

3  Description
   Each character after the string shifts to the right, and the last
   character disappears. The mvinsstr and mvwinsstr functions are
   specific to Compaq C for OpenVMS Systems and are not portable.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function makes the screen
                      scroll illegally. For more information, see
                      the scrollok function.
 

2  mvwin
   Moves the starting position of the window to the specified (y,x)
   coordinates.

   Format

     #include  <curses.h>

     mvwin  (WINDOW *win, int y, int x);
 

3  Arguments
 

win

   A pointer to the window.
 

y

   A window coordinate.
 

x

   A window coordinate.
 

3  Description
   When moving subwindows, the mvwin function does not rewrite the
   contents of the subwindow on the underlying window at the new
   position. If you write anything to the subwindow after the move,
   the function also writes to the underlying window.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that moving the window put part or
                      all of the window off the edge of the terminal
                      screen. The terminal screen remains unaltered.
 

2  nanosleep
   High-resolution sleep (REALTIME). Suspends a process (or thread
   in a threaded program) from execution for the specified timer
   interval.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <time.h>

     int nanosleep  (const struct timespec *rqtp, struct timespec *rmtp);
 

3  Arguments
 

rqtp

   A pointer to the timespec data structure that defines the time
   interval during which the calling process or thread is suspended.
 

rmtp

   A pointer to the timespec data structure that receives the amount
   of time remaining in the previously requested interval, or zero
   if the full interval has elapsed.
 

3  Description
   The nanosleep function suspends a process or thread until one of
   the following conditions is met:

   o  The time interval specified by the rqtp argument has elapsed.

   o  A signal is delivered to the calling process and the action
      is to invoke a signal-catching function or to terminate the
      process.

   The suspension time may be longer than requested because the
   argument value is rounded up to an integer multiple of the sleep
   resolution or because of the scheduling of other activity by the
   system. Except when interrupted by a signal, the suspension time
   is not less than the time specified by the rqtp argument (as
   measured by the system clock, CLOCK_REALTIME).

   The use of the nanosleep function has no effect on the action or
   blockage of any signal.

   If the requested time has elapsed, the call was successful and
   the nanosleep function returns zero.

   On failure, the nanosleep function returns -1 and sets errno
   to indicate the failure. The function fails if it has been
   interrupted by a signal, or if the rqtp argument specified
   a nanosecond value less than 0 or greater than or equal to 1
   billion.

   If the rmtp argument is non-NULL, the timespec structure it
   references is updated to contain the amount of time remaining in
   the interval (the requested time minus the time actually slept).

   If the rmtp argument is NULL, the remaining time is not returned.

   See also clock_getres, clock_gettime, clock_settime, and sleep.
 

3  Return_Values

   0                  Indicates success. The requested time has
                      elapsed.
   -1                 Indicates failure. The function call was
                      unsuccessful or was interrupted by a signal;
                      errno is set to one of the following values:

                      o  EINTR - The nanosleep function was
                         interrupted by a signal.

                      o  EINVAL - The rqtp argument specified a
                         nanosecond value less than 0 or greater
                         than or equal to 1 billion.
 

2  newwin
   Creates a new window with numlines lines and numcols columns
   starting at the coordinates (begin_y,begin_x) on the terminal
   screen.

   Format

     #include  <curses.h>

     WINDOW *newwin  (int numlines, int numcols, int begin_y, int
                     begin_x);
 

3  Arguments
 

numlines

   If it is 0, the newwin function sets that dimension to LINES
   (begin_y). To get a new window of dimensions LINES by COLS, use
   the following line:

   newwin (0, 0, 0, 0)
 

numcols

   If it is 0, the newwin function sets that dimension to COLS
   (begin_x). Therefore, to get a new window of dimensions LINES
   by COLS, use the following line:

   newwin (0, 0, 0, 0)
 

begin_y

   A window coordinate.
 

begin_x

   A window coordinate.
 

3  Return_Values

   x                  The address of the allocated window.
   ERR                Indicates an error.
 

2  nextafter
   Returns the next machine-representable number following x in the
   direction of y.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double nextafter  (double x, double y);

     float nextafterf  (float x, float y);

     long double nextafterl  (long double x, long double y);
 

3  Arguments
 

x

   A real number.
 

y

   A real number.
 

3  Description
   The nextafter functions return the next machine-representable
   floating-point number following x in the direction of y. If
   y is less than x, nextafter returns the largest representable
   floating-point number less than x.
 

3  Return_Values

   n                  The next representable floating-point value
                      following x in the direction of y.
   HUGE_VAL           Overflow; errno is set to ERANGE.
   NaN                x or y is NaN; errno is set to EDOM.
 

2  nexttoward
   Equivalent to the nextafter function, with exceptions noted in
   the Description.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double nexttoward  (double x, long double y);

     float nexttowardf  (float x, long double y);

     long double nexttowardl  (long double x, long double y);
 

3  Arguments
 

x

   A real number.
 

y

   A real number.
 

3  Description
   The nexttoward functions are equivalent to the corresponding
   nextafter functions, except that the second parameter has type
   long double and the functions return y converted to the type of
   the function if x equals y.
 

3  Return_Values

   n                  The next representable floating-point value
                      following x in the direction of y.
   y (of the type x)  If x equals y.
   HUGE_VAL           Overflow; errno is set to ERANGE.
   NaN                x or y is NaN; errno is set to EDOM.
 

2  nice
   Increases or decreases process priority relative to the process
   current priority by the amount of the argument. This function is
   nonreentrant.

   Format

     #include  <unistd.h>

     int nice  (int increment);
 

3  Argument
 

increment

   As a positive argument, decreases priority; as a negative
   argument, increases priority. Issuing nice(0) restores the
   base priority. The resulting priority cannot be less than 1,
   or greater than the process's base priority. If it is, the nice
   function quietly does nothing.
 

3  Description
   When a process calls the vfork function, the resulting child
   inherits the parent's priority.

   With the DECC$ALLOW_UNPRIVILEGED_NICE feature logical enabled,
   the nice function exhibits its legacy behavior of not checking
   the privilege of the calling process (that is, any user may lower
   the nice value to increase process priorities). Also, when the
   caller sets a priority above MAX_PRIORITY, the nice value is set
   to the base priority.

   With DECC$ALLOW_UNPRIVILEGED_NICE disabled, the nice function
   conforms to the X/Open standard of checking the privilege of the
   calling process (only users with ALTPRI privilege can lower the
   nice value to increase process priorities), and when the caller
   sets a priority above MAX_PRIORITY, the nice value is set to MAX_
   PRIORITY.

   See also vfork.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates failure.
 

2  nint
   Returns the nearest integral value to the argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double nint  (double x);

     float nintf  (float x,);

     long double nintl  (long double x);
 

3  Argument
 

x

   A real number.
 

3  Description
   The nint functions return the nearest integral value to x,
   except halfway cases are rounded to the integral value larger
   in magnitude. This corresponds to the Fortran generic intrinsic
   function nint.
 

3  Return_Values

   n                  The nearest integral value to x.
   NaN                x is NaN; errno is set to EDOM.
 

2  [no]nl
   The nl and nonl functions are provided only for UNIX software
   compatibility and have no function in the OpenVMS environment.

   Format

     #include  <curses.h>

     void nl  (void);

     void nonl  (void);
 

2  nl_langinfo
   Returns a pointer to a string that contains information obtained
   from the program's current locale.

   Format

     #include  <langinfo.h>

     char *nl_langinfo  (nl_item item);
 

3  Argument
 

item

   The name of a constant that specifies the information required.
   These constants are defined in <langinfo.h>.

   The following constants are valid:

   Constant     Category     Description

   D_T_FMT      LC_TIME      String for formatting date and time
   D_FMT        LC_TIME      String for formatting date
   T_FMT        LC_TIME      String for formatting time
   T_FMT_AMPM   LC_TIME      Time format with AM/PM string
   AM_STR       LC_TIME      String that represents AM in 12-hour
                             clock notation
   PM_STR       LC_TIME      String that represents PM in 12-hour
                             clock notation
   DAY_1        LC_TIME      The name of the first day of the week
    . . .
   DAY_7        LC_TIME      The name of the seventh day of the week
   ABDAY_1      LC_TIME      The abbreviated name of the first day
                             of the week
    . . .
   ABDAY_7      LC_TIME      The abbreviated name of the seventh day
                             of the week
   MON_1        LC_TIME      The name of the first month in the year
    . . .
   MON_12       LC_TIME      The name of the twelfth month in the
                             year
   ABMON_1      LC_TIME      The abbreviated name of the first month
                             in the year
    . . .
   ABMON_12     LC_TIME      The abbreviated name of the twelfth
                             month in the year
   ERA          LC_TIME      Era description strings
   ERA_D_FMT    LC_TIME      Era date format string
   ERA_T_FMT    LC_TIME      Era time format
   ERA_D_T_FMT  LC_TIME      Era date and time format
   ALT_DIGITS   LC_TIME      Alternative symbols for digits
   RADIXCHAR    LC_NUMERIC   The radix character
   THOUSEP      LC_NUMERIC   The character used to separate groups
                             of digits in nonmonetary values
   YESEXP       LC_MESSAGES  The expression for affirmative
                             responses to yes/no questions
   NOEXP        LC_MESSAGES  The expression for negative responses
                             to yes/no questions
   CRNCYSTR     LC_MONETARY  The currency symbol. It is preceded by
                             one of the following:

                             o  A minus (-)  if the symbol is to
                                appear before the value

                             o  A plus (+)  if the symbol is to
                                appear after the value

                             o  A period (.)  if the symbol replaces
                                the radix character

   CODESET      LC_CTYPE     Codeset name
 

3  Description
   If the current locale does not have language information defined,
   the function returns information from the C locale. The program
   should not modify the string returned by the function. This
   string might be overwritten by subsequent calls to nl_langinfo.

   If the setlocale function is called after a call to nl_langinfo,
   then the pointer returned by the previous call to nl_langinfo
   will be unspecified. In this case, the nl_langinfo function
   should be called again.
 

3  Return_Value

   x                  Pointer to the string containing the requested
                      information. If item is invalid, the function
                      returns an empty string.
 

3  Example

       #include <stdio.h>
       #include <locale.h>
       #include <langinfo.h>

       /* This test sets up the British English locale, and then       */
       /* inquires on the data and time format, first day of the week, */
       /* and abbreviated first day of the week.                       */

       #include <stdlib.h>
       #include <string.h>

       int main()
       {
           char *return_val;
           char *nl_ptr;

           /* set the locale, with user supplied locale name  */

           return_val = setlocale(LC_ALL, "en_gb.iso8859-1");
           if (return_val == NULL) {
               printf("ERROR : The locale is unknown");
               exit(1);
           }
           printf("+----------------------------------------+\n");

           /* Get the date and time format from the locale.  */

           printf("D_T_FMT = ");

           /*  Compare the returned string from nl_langinfo with */
           /*  an empty string.                                  */

           if (!strcmp((nl_ptr = (char *) nl_langinfo(D_T_FMT)), "")) {

         /* The string returned was empty this could mean that either */
         /* 1) The locale does not contain a value for this item      */
         /* 2) The value for this item is an empty string             */

               printf("nl_langinfo returned an empty string\n");
           }
           else {
               /* Display the date and time format  */

               printf("%s\n", nl_ptr);
           }

       /* Get the full name for the first day of the week from locale */
          printf("DAY_1 = ");

         /*  Compare the returned string from nl_langinfo with */
         /*  an empty string.                                  */

           if (!strcmp((nl_ptr = (char *) nl_langinfo(DAY_1)), "")) {

         /* The string returned was empty this could mean that either */
         /*    1) The locale does not contain a value for the first   */
         /*       day of the week                                     */
         /*    2) The value for the first day of the week is          */
         /*       an empty string                                     */

               printf("nl_langinfo returned an empty string\n");
           }

           else {
            /* Display the full name of the first day of the week     */

               printf("%s\n", nl_ptr);
           }
 /* Get the abbreviated name for the first day of the week from locale*/

           printf("ABDAY_1 = ");

        /* Compare the returned string from nl_
langinfo with an empty */
        /* string.                                                    */

           if (!strcmp((nl_ptr = (char *) nl_langinfo(ABDAY_1)), "")) {

        /* The string returned was empty this could mean that either  */
        /*    1) The locale does not contain a value for the first    */
        /*       day of the week                                      */
        /*    2) The value for the first day of the week is an        */
        /*       empty string                                         */

               printf("nl_langinfo returned an empty string\n");
           }

           else {

        /* Display the abbreviated name of the first day of the week  */

               printf("%s\n", nl_ptr);
          }
       }

     Running the example program produces the following result:

       +----------------------------------------+
       D_T_FMT = %a %e %b %H:%M:%S %Y
       DAY_1 = Sunday
       ABDAY_1 = Sun
 

2  nrand48
   Generates uniformly distributed pseudorandom-number sequences.
   Returns 48-bit signed long integers.

   Format

     #include  <stdlib.h>

     long int nrand48  (unsigned short int xsubi[3]);
 

3  Argument
 

xsubi

   An array of three short ints that, when concatenated together,
   form a 48-bit integer.
 

3  Description
   The nrand48 function generates pseudorandom numbers using the
   linear congruential algorithm and 48-bit integer arithmetic.

   The nrand48 function returns nonnegative, long integers uniformly
   distributed over the range of y values, such that 0 
   The function works by generating a sequence of 48-bit integer
   values, Xi, according to the linear congruential formula:

          Xn+1 = (aXn+c)mod m        n >= 0

   The argument m equals 248, so 48-bit integer arithmetic is

   performed. Unless you invoke the lcong48 function, the multiplier
   value a and the addend value c are:

         a = 5DEECE66D16 = 2736731631558

         c = B16 = 138

   The nrand48 function requires that the calling program pass an
   array as the xsubi argument, which for the first call must be
   initialized to the initial value of the pseudorandom-number
   sequence. Unlike the drand48 function, it is not necessary to
   call an initialization function prior to the first call.

   By using different arguments, the nrand48 function allows
   separate modules of a large program to generate several
   independent sequences of pseudorandom numbers. For example, the
   sequence of numbers that one module generates does not depend
   upon how many times the functions are called by other modules.
 

3  Return_Value

   n                  Returns nonnegative, long integers over the
                      range 0  

2  open
   Opens a file for reading, writing, or editing. It positions the
   file at its beginning (byte 0).

   Format

     #include  <fcntl.h>

     int open  (const char *file_spec, int flags, mode_t mode);        
               (ANSI C)

     int open  (const char *file_spec, int flags, . . . ); 
               (DEC C Extension)
 

3  Arguments
 

file_spec

   A null-terminated character string containing a valid file
   specification. If you specify a directory in the file_spec and
   it is a search list that contains an error, Compaq C interprets
   it as a file open error.

   If the file_spec parameter refers to a symbolic link, the open
   function opens the file pointed to by the symbolic link.
 

flags

   The following values are defined in the <fcntl.h> header file:

   O_RDONLY   Open for reading only
   O_WRONLY   Open for writing only
   O_RDWR     Open for reading and writing
   O_NDELAY   Open for asynchronous input
   O_APPEND   Append on each write
   O_CREAT    Create a file if it does not exist
   O_TRUNC    Create a new version of this file
   O_EXCL     Error if attempting to create existing file

   These flags are set using the bitwise OR operator (|)  to
   separate specified flags.

   Opening a file with O_APPEND causes each write on the file to
   be appended to the end. (In contrast, with the VAX C RTL the
   behavior of files opened in append mode was to start at EOF and,
   thereafter, write at the current file position.)

   If O_TRUNC is specified and the file exists, open creates a new
   file by incrementing the version number by 1, leaving the old
   version in existence.

   If O_CREAT is set and the named file does not exist, the Compaq C
   RTL creates it with any attributes specified in the fourth and
   subsequent arguments ( . . . ). If O_EXCL is set with O_CREAT and
   the named file exists, the attempted open returns an error.
 

mode

   An unsigned value that specifies the file-protection mode. The
   compiler performs a bitwise AND operation on the mode and the
   complement of the current protection mode.

   You can construct modes by using the bitwise OR operator (|)  to
   separate specified modes. The modes are:

   0400   OWNER:READ
   0200   OWNER:WRITE
   0100   OWNER:EXECUTE
   0040   GROUP:READ
   0020   GROUP:WRITE
   0010   GROUP:EXECUTE
   0004   WORLD:READ
   0002   WORLD:WRITE
   0001   WORLD:EXECUTE

   The system is given the same access privileges as the owner. A
   WRITE privilege also implies a DELETE privilege.
 

 . . .

   Optional file attribute arguments. The file attribute arguments
   are the same as those used in the creat function. For more
   information, see the creat function.
 

3  Description
   If a version of the file exists, a new file created with open
   inherits certain attributes from the existing file unless
   those attributes are specified in the open call. The following
   attributes are inherited: record format, maximum record size,
   carriage control, and file protection.

                                 NOTES

      o  If you intend to do random writing to a file, the file
         must be opened for update by specifying a flags value of
         O_RDWR.

      o  To create files with OpenVMS RMS default protections
         by using the UNIX system-call functions umask, mkdir,
         creat, and open, call mkdir, creat, and open with a
         file-protection mode argument of 0777 in a program that
         never specifically calls umask. These default protections
         include correctly establishing protections based on ACLs,
         previous versions of files, and so on.

         In programs that do vfork/exec calls, the new process
         image inherits whether umask has ever been called or not
         from the calling process image. The umask setting and
         whether the umask function has ever been called are both
         inherited attributes.

   See also creat, read, write, close, dup, dup2, and lseek.
 

3  Return_Values

   x                  A nonnegative file descriptor number.
   -1                 Indicates that the file does not exist, that
                      it is protected against reading or writing, or
                      that it cannot be opened for another reason.
 

3  Example

       #include <unixio.h>
       #include <fcntl.h>
       #include <stdlib.h>

       main()
       {
           int file,
               stat;
           int flags;

           flags = O_
RDWR;  /*  Open for read and write,            */
                            /*  with user default file protection,  */
                            /*  with max fixed record size of 2048, */
                            /*  and a block size of 2048 bytes.     */

       file=open("file.dat", flags, 0, "rfm=fix", "mrs=2048", "bls=2048");
           if (file == -1)
               perror("OPEN error"), exit(1);

           close(file);
       }
 

2  opendir
   Opens a specified directory.

   Format

     #include  <dirent.h>

     DIR *opendir  (const char *dir_name);
 

3  Argument
 

dir_name

   The name of the directory to be opened.
 

3  Description
   The opendir function opens the directory specified by dir_name
   and associates a directory stream with it. The dir_name argument
   can be specified in OpenVMS style or UNIX style. The directory
   stream is positioned at the first entry. The type DIR, defined
   in the <dirent.h> header file, represents a directory stream.
   A directory stream is an ordered sequence of all the directory
   entries in a particular directory.

   The opendir function also returns a pointer to identify the
   directory stream in subsequent operations. The NULL pointer is
   returned when the directory named by dir_name cannot be accessed,
   or when not enough memory is available to hold the entire stream.

                                 NOTES

      o  An open directory must always be closed with the closedir
         function to ensure that the next attempt to open that
         directory is successful. The opendir function should be
         used with readdir, closedir, and rewinddir to examine the
         contents of the directory.

      o  The opendir function supports UNIX style path name
         specifications.
 

3  Example

     See the program example in the description of closedir.
 

3  Return_Values

   x                  A pointer to an object of type DIR.
   NULL               Indicates an error; errno is set to one of the
                      following values:

                      o  EACCES - Search permission is denied
                         for any component of dir_name or read
                         permission is denied for dir_name.

                      o  ENAMETOOLONG - The length of the dir_name
                         string exceeds PATH_MAX, or a pathname
                         component is longer than NAME_MAX.

                      o  ENOENT - The dir_name argument points to
                         the name of a file that does not exist, or
                         is an empty string.
 

2  overlay
   Nondestructively superimposes win1 on win2. The function writes
   the contents of win1 that will fit onto win2 beginning at the
   starting coordinates of both windows. Blanks on win1 leave
   the contents of the corresponding space on win2 unaltered. The
   overlay function copies as much of a window's box as possible.

   Format

     #include  <curses.h>

     int overlay  (WINDOW *win1, WINDOW *win2);
 

3  Arguments
 

win1

   A pointer to the window.
 

win2

   A pointer to the window.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  overwrite
   Destructively writes the contents of win1 on win2.

   Format

     #include  <curses.h>

     int overwrite  (WINDOW *win1, WINDOW *win2);
 

3  Arguments
 

win1

   A pointer to the window.
 

win2

   A pointer to the window.
 

3  Description
   The overwrite function writes the contents of win1 that will fit
   onto win2 beginning at the starting coordinates of both windows.
   Blanks on win1 are written on win2 as blanks. This function
   copies as much of a window's box as possible.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates failure.
 

2  pathconf
   Retrieves file implementation characteristics.

   Format

     #include  <unistd.h>

     long int pathconf  (const char *path, int name);
 

3  Arguments
 

path

   The pathname of a file or directory.
 

name

   The configuration attribute to query. If this attribute is
   not applicable to the file specified by the path argument, the
   pathconf function returns an error.
 

3  Description
   The pathconf function allows an application to determine the
   characteristics of operations supported by the file system
   underlying the filenamed by path. Read, write, or execute
   permission of the named file is not required, but you must be
   able to search all directories in the path leading to the file.

   Symbolic values for the name argument are defined in the
   <unistd.h> header file, as follows:

   _PC_LINK_MAX    The maximum number of links to the file. If the
                   path argument refers to a directory, the value
                   returned applies to the directory itself.
   _PC_MAX_CANON   The maximum number of bytes in a canonical
                   input line. This is applicable only to terminal
                   devices.
   _PC_MAX_INPUT   The number of types allowed in an input queue.
                   This is applicable only to terminal devices.
   _PC_NAME_MAX    Maximum number of bytes in a filename (not
                   including a terminating null). The byte range
                   value is between 13 and 255. This is applicable
                   only to a directory file. The value returned
                   applies to filenames within the directory.
   _PC_PATH_MAX    Maximum number of bytes in a pathname (not
                   including a terminating null). The value is never
                   larger than 65,535. This is applicable only to a
                   directory file. The value returned is the maximum
                   length of a relative pathname when the specified
                   directory is the working directory.
   _PC_PIPE_BUF    Maximum number of bytes guaranteed to be written
                   atomically. This is applicable only to a FIFO.
                   The value returned applies to the referenced
                   object. If the path argument refers to a
                   directory, the value returned applies to any
                   FIFO that exists or can be created within the
                   directory.
   _PC_CHOWN_      This is applicable only to a directory file. The
   RESTRICTED      value returned applies to any files (other than
                   directories) that exist or can be created within
                   the directory.
   _PC_NO_TRUNC    Returns 1 if supplying a component name longer
                   than allowed by NAME_MAX causes an error. Returns
                   0 (zero) if long component names are truncated.
                   This is applicable only to a directory file.
   _PC_VDISABLE    This is always 0 (zero); no disabling character
                   is defined. This is applicable only to a terminal
                   device.
 

3  Return_Values

   x                  Resultant value of the configuration attribute
                      specified in name.
   -1                 Indicates an error; errno is set to one of the
                      following values:

                      o  EACCES - Search permission is denied for a
                         component of the path prefix.

                      o  EINVAL - The name argument specifies an
                         unknown or inapplicable characteristic.

                      o  EFAULT - The path argument is an invalid
                         address.

                      o  ENAMETOOLONG - The length of the path
                         string exceeds PATH_MAX or a pathname
                         component is longer than NAME_MAX.

                      o  ENOENT - The named file does not exist
                         or the path argument points to an empty
                         string.

                      o  ENOTDI - A component of the path prefix is
                         not a directory.
 

2  pause
   Suspends the calling process until delivery of a signal whose
   action is either to execute a signal-catching function or to
   terminate the process.

   Format

     #include  <unistd.h>

     int pause  (void);
 

3  Description
   The pause function suspends the calling process until delivery
   of a signal whose action is either to execute a signal-catching
   function or to terminate the process.

   If the action is to terminate the process, pause does not return.

   If the action is to execute a signal-catching function, pause
   returns after the signal-catching function returns.
 

3  Return_Value

                      Since the pause function suspends process
                      execution indefinitely unless interrupted by
                      a signal, there is no successful completion
                      return value.
   -1                 In cases where pause returns, the return value
                      is -1, and errno is set to EINTR.
 

2  pclose
   Closes a pipe to a process.

   Format

     #include  <stdio.h>

     int pclose  (FILE *stream);
 

3  Arguments
 

stream

   A pointer to a FILE structure for an open pipe returned by a
   previous call to the popen function.
 

3  Description
   The pclose function closes a pipe between the calling program and
   a shell command to be executed. Use pclose to close any stream
   you have opened with popen. The pclose function waits for the
   associated process to end, and then returns the exit status of
   the command. See the description of waitpid for information on
   interpreting the exit status.

   Beginning with OpenVMS Version 7.3-1, when compiled with the
   _VMS_WAIT macro defined, the pclose function returns the OpenVMS
   completion code of the child process.

   See also popen.
 

3  Return_Values

   x                  Exit status of child.
   -1                 Indicates an error. The stream argument is not
                      associated with a popen function. errno is set
                      to the following:

                      o  ECHILD - cannot obtain the status of the
                         child process.
 

2  perror
   Writes a short error message to stderr describing the current
   value of errno.

   Format

     #include  <stdio.h>

     void perror  (const char *str);
 

3  Argument
 

str

   Usually the name of the program that caused the error.
 

3  Description
   The perror function uses the error number in the external
   variable errno to retrieve the appropriate locale-dependent
   error message. The function writes out the message as follows:
   str (a user-supplied prefix to the error message), followed by a
   colon and a space, followed by the message itself, followed by a
   new-line character.

   See also strerror.
 

3  Example

       #include <stdio.h>
       #include <stdlib.h>

       main(argc, argv)
           int argc;
           char *argv[];
       {
           FILE *fp;

           fp = fopen(argv[1], "r");   /* Open an input file. */
           if (fp == NULL) {

               /* If the fopen call failed, perror prints out a        */
               /* diagnostic:                                          */
               /*                                                      */
               /*  "open: <error message>"                             */
               /*  This error message provides a diagnostic explaining */
               /*  the cause of the failure.                           */

               perror("open");
               exit(EXIT_FAILURE);
           }
           else
               fclose(fd) ;
       }
 

2  pipe
   Creates a temporary mailbox that can be used to read and write
   data between a parent and child process. The channels through
   which the processes communicate are called a pipe.

   Format

     #include  <unistd.h>

     int pipe  (int array_fdscptr[2]); (ISO POSIX-1)

     int pipe  (int array_fdscptr[2], . . . ); (DEC C Extension)
 

3  Arguments
 

array_fdscptr

   An array of file descriptors. A pipe is implemented as an
   array of file descriptors associated with a mailbox. These
   mailbox descriptors are special in that these are the only file
   descriptors which, when passed to the isapipe function, will
   return 1.

   The file descriptors are allocated in the following way:

   o  The first available file descriptor is assigned to writing,
      and the next available file descriptor is assigned to reading.

   o  The file descriptors are then placed in the array in reverse
      order; element 0 contains the file descriptor for reading, and
      element 1 contains the file descriptor for writing.
 

 . . .

   Represents three optional, positional arguments, flag, bufsize,
   and bufquota:
 

flag

   An optional argument used as a bitmask.

   If either the O_NDELAY or O_NONBLOCK bit is set, the I/O
   operations to the mailbox through array_fdscptr file descriptors
   terminate immediately, rather than waiting for another process.

   If, for example, the O_NDELAY bit is set and the child issues
   a read request to the mailbox before the parent has put any
   data into it, the read terminates immediately with 0 status.
   If neither the O_NDELAY nor O_NONBLOCK bit is set, the child
   will be waiting on the read until the parent writes any data into
   the mailbox. This is the default behavior if no flag argument is
   specified.

   The values of O_NDELAY and O_NONBLOCK are defined in the
   <fcntl.h> header file. Any other bits in the flag argument are
   ignored. You must specify this argument if the second optional,
   positional argument bufsize is specified. If the flag argument
   is needed only to allow specification of the bufsize argument,
   specify flag as 0.
 

bufsize

   Optional argument of type int that specifies the size of the
   mailbox, in bytes. Specify a value from 512 to 65535.

   If you specify 0 or omit this argument, the operating system
   creates a mailbox with a default size of 512 bytes.

   If you specify a value less than 0 or larger than 65535, the
   results are unpredictable.

   If you do specify this argument, be sure to precede it with a
   flag argument.

   The DECC$PIPE_BUFFER_SIZE feature logical can also be used to
   specify the size of the mailbox. If bufsize is supplied, it takes
   precedence over the value of DECC$PIPE_BUFFER_SIZE. Otherwise,
   the value of DECC$PIPE_BUFFER_SIZE is used.

   If neither bufsize nor DECC$PIPE_BUFFER_SIZE is specified, the
   default buffer size of 512 is used.
 

bufquota

   Optional argument of type int that specifies the buffer quota of
   the pipe's mailbox. Specify a value from 512 to 2147483647.

   OpenVMS Version 7.3-2 added this argument. In previous OpenVMS
   versions, the buffer quota was equal to the buffer size.

   The DECC$PIPE_BUFFER_QUOTA feature logical can also be used to
   specify the buffer quota. If the optional bufquota argument of
   the pipe function is supplied, it takes precedence over the value
   of DECC$PIPE_BUFFER_QUOTA. Otherwise, the value of DECC$PIPE_
   BUFFER_QUOTA is used.

   If neither bufquota nor DECC$PIPE_BUFFER_QUOTA is specified, then
   the buffer quota defaults to the buffer size.
 

3  Description
   The mailbox used for the pipe is a temporary mailbox. The mailbox
   is not deleted until all processes that have open channels to
   that mailbox close those channels. The last process that closes a
   pipe writes a message to the mailbox, indicating the end-of-file.

   The mailbox is created by using the $CREMBX system service,
   specifying the following characteristics:

   o  A maximum message length of 512 characters

   o  A buffer quota of 512 characters

   o  A protection mask granting all privileges to USER and GROUP
      and no privileges to SYSTEM or WORLD

   The buffer quota of 512 characters implies that you cannot write
   more than 512 characters to the mailbox before all or part of the
   mailbox is read. Since a mailbox record is slightly larger than
   the data part of the message that it contains, not all of the
   512 characters can be used for message data. You can increase the
   size of the buffer by specifying an alternative size using the
   optional, third argument to the pipe function. A pipe under the
   OpenVMS system is a stream-oriented file with no carriage-control
   attributes. It is fully buffered by default in the Compaq C RTL.
   A mailbox used as a pipe is different than a mailbox created by
   the application. A mailbox created by the application defaults
   to a record-oriented file with carriage return, carriage control.
   Additionally, writing a zero-length record to a mailbox writes an
   EOF, as does each close of the mailbox. For a pipe, only the last
   close of a pipe writes an EOF.

   The pipe is created by the parent process before vfork and
   an exec function are called. By calling pipe first, the child
   inherits the open file descriptors for the pipe. You can then use
   the getname function to return the name of the mailbox associated
   with the pipe, if this information is desired. The mailbox name
   returned by getname has the format _MBAnnnn: (Alpha only) or _
   MBAnnnnn: (Integrity servers(ONLY)) , where nnnn or nnnnn is a
   unique number.

   Both the parent and the child need to know in advance which file
   descriptors will be allocated for the pipe. This information
   cannot be retrieved at run time. Therefore, it is important to
   understand how file descriptors are used in any Compaq C for
   OpenVMS program.

   File descriptors 0, 1, and 2 are open in a Compaq C for OpenVMS
   program for stdin (SYS$INPUT), stdout (SYS$OUTPUT), and stderr
   (SYS$ERROR), respectively. Therefore, if no other files are open
   when pipe is called, pipe assigns file descriptor 3 for writing
   and file descriptor 4 for reading. In the array returned by pipe,
   4 is placed in element 0 and 3 is placed in element 1.

   If other files have been opened, pipe assigns the first
   available file descriptor for writing and the next available
   file descriptor for reading. In this case, the pipe does not
   necessarily use adjacent file descriptors. For example, assume
   that two files have been opened and assigned to file descriptors
   3 and 4 and the first file is then closed. If pipe is called at
   this point, file descriptor 3 is assigned for writing and file
   descriptor 5 is assigned for reading. Element 0 of the array will
   contain 5 and element 1 will contain 3.

   In large applications that do large amounts of I/O, it gets
   more difficult to predict which file descriptors are going to
   be assigned to a pipe; and, unless the child knows which file
   descriptors are being used, it will not be able to read and write
   successfully from and to the pipe.

   One way to be sure that the correct file descriptors are being
   used is to use the following procedure:

   1. Choose two descriptor numbers that will be known to both the
      parent and the child. The numbers should be high enough to
      account for any I/O that might be done before the pipe is
      created.

   2. Call pipe in the parent at some point before calling an exec
      function.

   3. In the parent, use dup2 to assign the file descriptors
      returned by pipe to the file descriptors you chose. This now
      reserves those file descriptors for the pipe; any subsequent
      I/O will not interfere with the pipe.

   You can read and write through the pipe using the UNIX I/O
   functions read and write, specifying the appropriate file
   descriptors. As an alternative, you can issue fdopen calls to
   associate file pointers with these file descriptors so that you
   can use the Standard I/O functions (fread and fwrite).

   Two separate file descriptors are used for reading from and
   writing to the pipe, but only one mailbox is used so some I/O
   synchronization is required. For example, assume that the parent
   writes a message to the pipe. If the parent is the first process
   to read from the pipe, then it will read its own message back as
   shown in Reading and Writing to a Pipe.
 

                                  NOTE

      For added UNIX portability, you can use the following
      feature logicals to control the behavior of the C RTL pipe
      implementation:

      o  Define the DECC$STREAM_PIPE feature logical name to
         ENABLE to direct the pipe function to use stream I/O
         instead of record I/O.

      o  Define the DECC$POPEN_NO_CRLF_REC_ATTR feature logical
         to ENABLE to prevent CR/LF carriage control from being
         added to pipe records for pipes opened with the popen
         function. Be aware that enabling this feature might
         result in undesired behavior from other functions such
         as gets that rely on the carriage-return character.

   Figure REF-1  Reading and Writing to a Pipe
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error.
 

2  poll
   Provides users with a mechanism for multiplexing input/output
   over a set of file descriptors that reference open streams.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <poll.h>

     int poll  (struct pollfd filedes [], nfds_t nfds, int timeout);
 

3  Argument
 

filedes

   Points to an array of pollfd structures, one for each file
   descriptor of interest. Each pollfd structure includes the
   following members:

      int fd - The file descriptor
      int events - The requested conditions
      int revents - The reported conditions
 

nfds

   The number of pollfd structures in the filedes array.
 

timeout

   The maximum length of time (in milliseconds) to wait for at least
   one of the specified events to occur.
 

3  Description
   The poll function provides users with a mechanism for
   multiplexing input/output over a set of file descriptors that
   reference open streams. For each member of the array pointed
   to by filedes, poll examines the given file descriptor for the
   event(s) specified in events. The poll function identifies those
   streams on which an application can send or receive messages, or
   on which certain events have occurred.

   The filedes parameter specifies the file descriptor to be
   examined and the events of interest for each file descriptor.
   It is a pointer to an array of pollfd structures. The fd member
   of each pollfd structure specifies an open file descriptor. The
   poll function uses the events member to determine what conditions
   to report for this file descriptor. If one or more of these
   conditions is true, the poll function sets the associated revents
   member.

   The events and revents members of each pollfd structure are
   bitmasks. The calling process sets the events bitmask, and poll
   sets the revents bitmasks. These bitmasks contain inclusive
   ORed combinations of condition options. The following condition
   options are defined:

      POLLERR - An error has occurred on the file descriptor. This
      option is only valid in the revents bitmask; it is not used in
      the events member.

      For STREAMS devices, if an error occurs on the file descriptor
      and the device is also disconnected, poll returns POLLERR;
      POLLERR takes precedence over POLLHUP.

      POLLHUP - The device has been disconnected. This event
      is mutually exclusive with POLLOUT; a stream can never be
      writable if a hangup occurred. However, this event and POLLIN,
      POLLRDNORM, POLLRDBAND or POLLPRI are not mutually exclusive.
      This option is only valid in the revents bitmask; it is
      ignored in the events member.


      POLLIN - Data other than high-priority data may be read
      without blocking. This option is set in revents even if the
      message is of zero length. In revents, this option is mutually
      exclusive with POLLPRI.


      POLLNVAL - The value specified for fd is invalid. This option
      is only valid in the revents member; it is ignored in the
      events member.


      POLLOUT - Normal (priority band equals 0) data may be written
      without blocking.


      POLLPRI - High-priority data may be received without blocking.
      This option is set in revents even if the message is of zero
      length. In revents, this option is mutually exclusive with
      POLLIN.


      POLLRDBAND - Data from a nonzero priority band may be read
      without blocking. This option is set in revents even if the
      message is of zero length.


      POLLRDNORM - Normal data (priority band equals 0) may be read
      without blocking. This option is set in revents even if the
      message is of zero length.


      POLLWRBAND - Priority data (priority band greater than 0)
      may be written. This event only examines bands that have been
      written to at least once.


      POLLWRNORM - Same as POLLOUT.

   The poll function ignores any pollfd structure whose fd member
   is less than 0 (zero). If the fd member of all pollfd structures
   is less than 0, the poll function will return 0 and have no other
   results.

   The conditions indicated by POLLNORM and POLLOUT are true if and
   only if at least one byte of data can be read or written without
   blocking. There are two exceptions: regular files, which always
   poll true for POLLNORM and POLLOUT, and pipes, when the rules
   for the operation specify to return zero in order to indicate
   end-of-file.

   The condition options POLLERR, POLLHUP, and POLLNVAL are always
   set in revents if the conditions they indicate are true for the
   specified file descriptor, whether or not these options are set
   in events.

   For each call to the poll function, the set of reportable
   conditions for each file descriptor consists of those conditions
   that are always reported, together with any further conditions
   for which options are set in events. If any reportable condition
   is true for any file descriptor, the poll function will return
   with options set in revents for each true condition for that file
   descriptor.

   If no reportable condition is true for any of the file
   descriptors, the poll function waits up to timeout milliseconds
   for a reportable condition to become true. If, in that time
   interval, a reportable condition becomes true for any of the file
   descriptors, poll reports the condition in the file descriptor's
   associated revents member and returns. If no reportable condition
   becomes true, poll returns without setting any revents bitmasks.

   If the timeout parameter is a value of -1, the poll function does
   not return until at least one specified event has occurred. If
   the value of the timeout parameter is 0 (zero), the poll function
   does not wait for an event to occur but returns immediately, even
   if no specified event has occurred.

   The behavior of the poll function is not affected by whether
   the O_NONBLOCK option is set on any of the specified file
   descriptors.

   The poll function supports regular files, terminal and pseudo-
   terminal devices, STREAMS-based files, FIFOs, and pipes. The
   behavior of poll on elements of file descriptors that refer to
   other types of files is unspecified.

   For sockets, a file descriptor for a socket that is listening for
   connections indicates it is ready for reading after connections
   are available. A file descriptor for a socket that is connecting
   asynchronously indicates it is ready for writing after a
   connection is established.
 

3  Return_Values

   n                  Upon successful completion, a nonnegative
                      value is returned, indicating the number of
                      file descriptors for which poll has set the
                      revents bitmask.
   0                  poll has timed out and has not set any of the
                      revents bitmasks.
   -1                 An error occurred. errno is set to indicate
                      the error:

                      o  EAGAIN - Allocation of internal data
                         structures failed. A later call to the
                         poll function might complete successfully.

                      o  EINTR - A signal was intercepted during the
                         poll function, and the signal handler was
                         installed with an indication that functions
                         are not to be restarted.

                      o  EINVAL - The nfds parameter is greater than
                         OPEN_MAX, or one of the fd members refers
                         to a stream or multiplexer that is linked
                         (directly or indirectly) downstream from a
                         multiplexer.
 

2  popen
   Initiates a pipe to a process.

   Format

     #include  <stdio.h>

     FILE *popen  (const char *command, const char *type);
 

3  Arguments
 

command

   A pointer to a null-terminated string containing a shell command
   line.
 

type

   A pointer to a null-terminated string containing an I/O mode.
   Because open files are shared, you can use a type r command as
   an input filter and a type w command as an output filter. Specify
   one of the following values for the type argument:

   o  r-the calling program can read from the standard output of the
      command by reading from the returned file stream.

   o  w-the calling program can write to the standard input of the
      command by writing to the returned file stream.
 

3  Description
   The popen function creates a pipe between the calling program
   and a shell command awaiting execution. It returns a pointer to a
   FILE structure for the stream.

   The popen function uses the value of the DECC$PIPE_BUFFER_SIZE
   feature logical to set the buffer size of the mailbox it creates
   for the pipe. You can specify a DECC$PIPE_BUFFER_SIZE value of
   512 to 65024 bytes. If DECC$PIPE_BUFFER_SIZE is not specified,
   the default buffer size of 512 is used.

                                 NOTES

      o  When you use the popen function to invoke an output
         filter, beware of possible deadlock caused by output
         data remaining in the program buffer. You can avoid this
         by either using the setvbuf function to ensure that the
         output stream is unbuffered, or the fflush function to
         ensure that all buffered data is flushed before calling
         the pclose function.

      o  For added UNIX portability, you can use the following
         feature logicals to control the behavior of the C RTL
         pipe implementation:

         -  Define the DECC$STREAM_PIPE feature logical name to
            ENABLE to direct the pipe function to use stream I/O
            instead of record I/O.

         -  Define the DECC$POPEN_NO_CRLF_REC_ATTR feature logical
            to ENABLE to prevent CR/LF carriage control from being
            added to pipe records for pipes opened with the popen
            function. Be aware that enabling this feature might
            result in undesired behavior from other functions such
            as gets that rely on the carriage-return character.

   See also fflush, pclose, and setvbuf.
 

3  Return_Values

   x                  A pointer to the FILE structure for the opened
                      stream.
   NULL               Indicates an error. Unable to create files or
                      processes.
 

2  pow
   Returns the first argument raised to the power of the second
   argument.

   Format

     #include  <math.h>

     double pow  (double x, double y);

     float powf  (float x, float y); (Integrity servers, Alpha)

     long double powl  (long double x, long double y);       
                       (Integrity servers, Alpha)
 

3  Arguments
 

x

   A floating-point base to be raised to an exponent y.
 

y

   The exponent to which the base x is to be raised.
 

3  Description
   The pow functions raise a floating-point base x to a floating-
   point exponent y. The value of pow(x,y) is computed as e**(y
   ln(x)) for positive x.

   If x is 0 and y is negative, HUGE_VAL is returned and errno is
   set to ERANGE or EDOM.
 

3  Return_Values

   x                  The result of the first argument raised to the
                      power of the second.
   1.0                The base is 0 and the exponent is 0.
   HUGE_VAL           The result overflowed; errno is set to ERANGE.
   HUGE_VAL           The base is 0 and the exponent is negative;
                      errno is set to ERANGE or EDOM.
 

3  Example

       #include <stdio.h>
       #include <math.h>
       #include <errno.h>

       main()
       {
           double x;

           errno = 0;

           x = pow(-3.0, 2.0);
           printf("%d, %f\n", errno, x);
       }

     This example program outputs the following:

       0, 9.000000
 

2  pread
   Reads bytes from a given position within a file without changing
   the file pointer.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     ssize_t pread  (int file_desc, void *buffer, size_t nbytes,

                    off_t offset);
 

3  Arguments
 

file_desc

   A file descriptor that refers to a file currently opened for
   reading.
 

buffer

   The address of contiguous storage in which the input data is
   placed.
 

nbytes

   The maximum number of bytes involved in the read operation.
 

offset

   The offset for the desired position inside the file.
 

3  Description
   The pread function performs the same action as read, except that
   it reads from a given position in the file without changing the
   file pointer. The first three arguments to pread are the same as
   for read, with the addition of a fourth argument offset for the
   desired position inside the file. An attempt to perform a pread
   on a file that is incapable of seeking results in an error.
 

3  Return_Values

   n                  The number of bytes read.
   -1                 Upon failure, the file pointer remains
                      unchanged and pread sets errno to one of the
                      following values:

                      o  EINVAL - The offset argument is invalid.
                         The value is negative.

                      o  EOVERFLOW - The file is a regular file, and
                         an attempt was made to read or write at or
                         beyond the offset maximum associated with
                         the file.

                      o  ENXIO - A request was outside the
                         capabilities of the device.

                      o  ESPIPE - fildes is associated with a pipe
                         or FIFO.
 

2  printf
   Performs formatted output from the standard output (stdout).

   Format

     #include  <stdio.h>

     int printf  (const char *format_spec, . . . );
 

3  Arguments
 

format_spec

   Characters to be written literally to the output or converted as
   specified in the . . . arguments.
 

 . . .

   Optional expressions whose resultant types correspond to
   conversion specifications given in the format specification.

   If no conversion specifications are given, you may omit the
   output sources. Otherwise, the function call must have exactly
   as many output sources as there are conversion specifications,
   and the conversion specifications must match the types of the
   output sources.

   Conversion specifications are matched to output sources in left-
   to-right order. Excess output pointers, if any, are ignored.
 

3  Return_Values

   x                  The number of bytes written.
   Negative value     Indicates that an output error occurred.
                      The function sets errno. For a list of errno
                      values set by this function, see fprintf.
 

2  [w]printw
   Perform a printf in the specified window, starting at the current
   position of the cursor. The printw function acts on the stdscr
   window.

   Format

     #include  <curses.h>

     printw  (char *format_spec, . . . );

     int wprintw  (WINDOW *win, char *format_spec, . . . );
 

3  Arguments
 

win

   A pointer to the window.
 

format_spec

   A pointer to the format specification string.
 

 . . .

   Optional expressions whose resultant types correspond to
   conversion specifications given in the format specification.

   If no conversion specifications are given, you may omit the
   output sources. Otherwise, the function call must have exactly
   as many output sources as there are conversion specifications,
   and the conversion specifications must match the types of the
   output sources.

   Conversion specifications are matched to output sources in left-
   to-right order. Excess output pointers, if any, are ignored.
 

3  Description
   The formatting specification (format_spec) and the other
   arguments are identical to those used with the printf function.

   The printw and wprintw functions format and then print the
   resultant string to the window using the addstr function. For
   more information, see the printf and scrollok functions in this
   section.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function makes the window
                      scroll illegally.
 

2  putc
   The putc macro writes a single character to a specified file.

   Format

     #include  <stdio.h>

     int putc  (int character, FILE *file_ptr);
 

3  Arguments
 

character

   The character to be written.
 

file_ptr

   A file pointer to the output stream.
 

3  Description
   The putc macro writes the byte character (converted to an
   unsigned char) to the output specified by the file_ptr parameter.
   The byte is written at the position at which the file pointer
   is currently pointing (if defined) and advances the indicator
   appropriately. If the file cannot support positioning requests,
   or if the output stream was opened with append mode, the byte is
   appended to the output stream.

   Since putc is a macro, a file pointer argument with side effects
   (for example, putc (ch, *f++)) might be evaluated incorrectly. In
   such a case, use the fputc function instead.

   Compiling with the __UNIX_PUTC macro defined enables an
   optimization that uses a faster, inlined version of this
   function.

   See also putc_unlocked.
 

3  Return_Values

   x                  The character written to the file. Indicates
                      success.
   EOF                Indicates output errors.
 

2  putc_unlocked
   Same as putc, except used only within a scope protected by
   flockfile and funlockfile.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     int putc_unlocked  (int character, FILE *file_ptr);
 

3  Argument
 

character

   The character to be written.
 

file_ptr

   A file pointer to the output stream.
 

3  Description
   The reentrant version of the putc macro is locked against
   multiple threads calling it simultaneously. This incurs overhead
   to ensure integrity of the stream. The unlocked version of this
   call, putc_unlocked can be used to avoid the overhead. The putc_
   unlocked macro is functionally identical to the putc macro,
   except that it is not required to be implemented in a thread-
   safe manner. The putc_unlocked macro can be safely used only
   within a scope that is protected by the flockfile and funlockfile
   functions used as a pair. The caller must ensure that the stream
   is locked before putc_unlocked is used.

   Since putc_unlocked is a macro, a file pointer argument with side
   effects might be evaluated incorrectly. In such a case, use the
   fputc_unlocked function instead.

   Compiling with the __UNIX_PUTC macro defined enables an
   optimization that uses a faster, inlined version of this
   function.

   See also flockfile, ftrylockfile, and funlockfile.
 

3  Return_Values

   x                  The character written to the file. Indicates
                      success.
   EOF                Indicates the end-of-file or an error.
 

2  putchar
   Writes a single character to the standard output (stdout) and
   returns the character.

   Format

     #include  <stdio.h>

     int putchar  (int character);
 

3  Argument
 

character

   An object of type int.
 

3  Description
   The putchar function is identical to fputc (character, stdout).

   Compiling with the __UNIX_PUTC macro defined enables an
   optimization that uses a faster, inlined version of this
   function.
 

3  Return_Values

   character          Indicates success.
   EOF                Indicates output errors.
 

2  putchar_unlocked
   Same as putchar, except used only within a scope protected by
   flockfile and funlockfile.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     int putchar_unlocked  (int character);
 

3  Argument
 

character

   An object of type int.
 

3  Description
   The reentrant version of the putchar function is locked against
   multiple threads calling it simultaneously. This incurs overhead
   to ensure integrity of the output stream. The unlocked version of
   this call, putchar_unlocked can be used to avoid the overhead.
   The putchar_unlocked function is functionally identical to
   the putchar function, except that it is not required to be
   implemented in a thread-safe manner. The putchar_unlocked
   function can be safely used only within a scope that is protected
   by the flockfile and funlockfile functions used as a pair. The
   caller must ensure that the stream is locked before putchar_
   unlocked is used.

   Compiling with the __UNIX_PUTC macro defined enables an
   optimization that uses a faster, inlined version of this
   function.

   See also flockfile, ftrylockfile, and funlockfile.
 

3  Return_Values

   x                  The next character from stdin, converted to
                      int.
   EOF                Indicates the end-of-file or an error.
 

2  putenv
   Sets an environmental variable.

   Format

     #include  <stdlib.h>

     int putenv  (const char *string);
 

3  Argument
 

string

   A pointer to a name=value string.
 

3  Description
   The putenv function sets the value of an environment variable
   by altering an existing variable or by creating a new one. The
   string argument points to a string of the form name=value, where
   name is the environment variable and value is the new value for
   it.

   The string pointed to by string becomes part of the environment,
   so altering the string changes the environment. When a new
   string-defining name is passed to putenv, the space used by
   string is no longer used.

                                 NOTES

      o  The putenv function manipulates the environment pointed
         to by the environ external variable, and can be used with
         getenv. However, the third argument to the main function
         (the environment pointer), is not changed.

         The putenv function uses the malloc function to enlarge
         the environment.

         A potential error is to call putenv with an automatic
         variable as the argument, then exit the calling function
         while string is still part of the environment.

      o  Do not use the setenv, getenv, and putenv functions
         to manipulate symbols and logicals. Instead, use the
         OpenVMS library calls lib$set_logical, lib$get_logical,
         lib$set_symbol, and lib$get_symbol. The *env functions
         deliberately provide UNIX behavior, and are not a
         substitute for these OpenVMS runtime library calls.

         OpenVMS DCL symbols, not logical names, are the closest
         analog to environment variables on UNIX systems. While
         getenv is a mechanism to retrieve either a logical name
         or a symbol, it maintains an internal cache of values for
         use with setenv and subsequent getenv calls. The setenv
         function does not write or create DCL symbols or OpenVMS
         logical names.

         This is consistent with UNIX behavior. On UNIX systems,
         setenv does not change or create any symbols that will be
         visible in the shell after the program exits.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error. errno is set to ENOMEM-
                      Not enough memory available to expand the
                      environment list.
 

3  Restriction
   The putenv function cannot take a 64-bit address.
 

2  puts
   Writes a character string to the standard output (stdout)
   followed by a new-line character.

   Format

     #include  <stdio.h>

     int puts  (const char *str);
 

3  Argument
 

str

   A pointer to a character string.
 

3  Description
   The puts function does not copy the terminating null character to
   the output stream.
 

3  Return_Values

   Nonnegative value  Indicates success.
   EOF                Indicates output errors.
 

2  putw
   Writes characters to a specified file.

   Format

     #include  <stdio.h>

     int putw  (int integer, FILE *file_ptr);
 

3  Arguments
 

integer

   An object of type int or long.
 

file_ptr

   A file pointer.
 

3  Description
   The putw function writes four characters to the output file as an
   int. No conversion is performed.
 

3  Return_Values

   integer            Indicates success.
   EOF                Indicates output errors.
 

2  putwc
   Converts a wide character to its corresponding multibyte value,
   and writes the result to a specified file.

   Format

     #include  <wchar.h>

     wint_t putwc  (wint_t wc, FILE *file_ptr);
 

3  Arguments
 

wc

   An object of type wint_t.
 

file_ptr

   A file pointer.
 

3  Description
   Since putwc might be implemented as a macro, a file pointer
   argument with side effects (for example putwc (wc, *f++)) might
   be evaluated incorrectly. In such a case, use the fputwc function
   instead.

   See also fputwc.
 

3  Return_Values

   x                  The character written to the file. Indicates
                      success.
   WEOF               Indicates an output error. The function sets
                      errno. For a list of the errno values set by
                      this function, see fputwc.
 

2  putwchar
   Writes a wide character to the standard output (stdout) and
   returns the character.

   Format

     #include  <wchar.h>

     wint_t putwchar  (wint_t wc);
 

3  Arguments
 

wc

   An object of type wint_t.
 

3  Description
   The putwchar function is identical to fputwc(wc, stdout).
 

3  Return_Values

   x                  The character written to the file. Indicates
                      success.
   WEOF               Indicates an output error. The function sets
                      errno. For a list of the errno values set by
                      this function, see fputwc.
 

2  pwrite
   Writes into a given position within a file without changing the
   file pointer.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     ssize_t pwrite  (int file_desc, const void *buffer, size_t
                     nbytes, off_t offset);
 

3  Arguments
 

file_desc

   A file descriptor that refers to a file currently opened for
   writing or updating.
 

buffer

   The address of contiguous storage from which the output data is
   taken.
 

nbytes

   The maximum number of bytes involved in the write operation.
 

offset

   The offset for the desired position inside the file.
 

3  Description
   The pwrite function performs the same action as write, except
   that it writes into a given position in the file without changing
   the file pointer. The first three arguments to pwrite are the
   same as for write, with the addition of a fourth argument offset
   for the desired position inside the file.
 

3  Return_Values

   n                  The number of bytes written.
   -1                 Upon failure, the file pointer remains
                      unchanged and pwrite sets errno to one of
                      the following values:

                      o  EINVAL - The offset argument is invalid.
                         The value is negative.

                      o  ESPIPE - fildes is associated with a pipe
                         or FIFO.
 

2  qabs,llabs
   Returns the absolute value of an integer as an __int64. llabs is
   a synonym for qabs.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdlib.h>

     __int64 qabs  (__int64  j);

     __int64 llabs  (__int64  j);
 

3  Argument
 

j

   A value of type __int64.
 

2  qdiv,lldiv
   Returns the quotient and the remainder after the division of its
   arguments. lldiv is a synonym for qdiv.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdlib.h>

     qdiv_t qdiv  (__int64 numer, __int64  denom);

     lldiv_t lldiv  (__int64 numer, __int64  denom);
 

3  Arguments
 

numer

   A numerator of type __int64.
 

denom

   A denominator of type __int64.
 

3  Description
   The types qdiv_t and lldiv_t are defined in the <stdlib.h> header
   file as follows:

   typedef struct
            {
            __int64 quot, rem;
            } qdiv_t, lldiv_t;
 

2  qsort
   Sorts an array of objects in place. It implements the quick-sort
   algorithm.

   Format

     #include  <stdlib.h>

     void qsort  (void *base, size_t nmemb, size_t size, int   
                 (*compar) (const void *, const void *));
 

3  Function_Variants
   The qsort function has variants named _qsort32 and _qsort64 for
   use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

base

   A pointer to the first member of the array. The pointer should be
   of type pointer-to-element and cast to type pointer-to-character.
 

nmemb

   The number of objects in the array.
 

size

   The size of an object, in bytes.
 

compar

   A pointer to the comparison function.
 

3  Description
   Two arguments are passed to the comparison function pointed to
   by compar. The two arguments point to the objects being compared.
   Depending on whether the first argument is less than, equal to,
   or greater than the second argument, the comparison function
   returns an integer less then, equal to, or greater than 0.

   The comparison function compar need not compare every byte, so
   arbitrary data might be contained in the objects in addition to
   the values being compared.

   The order in the output of two objects that compare as equal is
   unpredictable.
 

2  raise
   Generates a specified software signal. Generating a signal causes
   the action routine established by the signal, ssignal, or sigvec
   function to be invoked.

   Format

     #include  <signal.h>

     int raise  (int sig); (ANSI C)

     int raise  (int sig[, int sigcode]); (DEC C Extension)
 

3  Arguments
 

sig

   The signal to be generated.
 

sigcode

   An optional signal code, available only when not compiling in
   strict ANSI C mode. For example, signal SIGFPE-the arithmetic
   trap signal-has 10 different codes, each representing a different
   type of arithmetic trap.

   The signal codes can be represented by mnemonics or numbers. The
   arithmetic trap codes are represented by the numbers 1 to 10;
   the SIGILL codes are represented by the numbers 0 to 2. The code
   values are defined in the <signal.h> header file.
 

3  Description
   Calling the raise function has one of the following results:

   o  If raise specifies a sig argument that is outside the range
      defined in the <signal.h> header file, then the raise function
      returns 0, and the errno variable is set to EINVAL.

   o  If signal, ssignal, or sigvec establishes SIG_DFL (default
      action) for the signal, then the functions do not return. The
      image is exited with the OpenVMS error code corresponding to
      the signal.

   o  If signal, ssignal, or sigvec establishes SIG_IGN (ignore
      signal) as the action for the signal, then raise returns its
      argument, sig.

   o  signal, ssignal, or sigvec must establish an action function
      for the signal. That function is called and its return value
      is returned by raise.

   See also gsignal, signal, ssignal, and sigvec.
 

3  Return_Values

   0                  If successful.
   nonzero            If unsuccessful.
 

2  rand
   Returns pseudorandom numbers in the range 0 to 2[31] - 1.

   Format

     #include  <stdlib.h>

     int rand  (void);

     int rand_r  (unsigned int seed); (Integrity servers, Alpha)
 

3  Argument
 

seed

   An initial seed value.
 

3  Description
   The rand function computes a sequence of pseudorandom integers in
   the range 0 to {RAND_MAX} with a period of at least 2[32].

   The rand_r function computes a sequence of pseudorandom integers
   in the range 0 to {RAND_MAX}. The value of the {RAND_MAX} macro
   will be at least 32767.

   If rand_r is called with the same initial value for the object
   pointed to by seed and that object is not modified between
   successive returns and calls to rand_r, the same sequence is
   generated.

   See also srand.

   For other random-number algorithms, see random and all the *48
   functions.
 

3  Return_Value

   n                  A pseudorandom number.
 

2  random
   Generates pseudorandom numbers in a more random sequence.

   Format

     #include  <stdlib.h>

     long int random  (void);
 

3  Description
   The random function is a random-number generator that has
   virtually the same calling sequence and initialization properties
   as the rand function, but produces sequences that are more
   random. The low 12 bits generated by rand go through a cyclic
   pattern. All bits generated by random are usable. For example,
   random() &1 produces a random binary value.

   The random function uses a nonlinear, additive-feedback, random-
   number generator employing a default state-array size of 31
   integers to return successive pseudorandom numbers in the range
   from 0 to 231 - 1. The period of this random-number generator is

   approximately 16*(231 -1). The size of the state array determines

   the period of the random-number generator. Increasing the state
   array size increases the period.

   With a full 256 bytes of state information, the period of the
   random-number generator is greater than 269, and is sufficient

   for most purposes.

   Like the rand function, the random function produces by default a
   sequence of numbers that you can duplicate by calling the srandom
   function with a value of 1 as the seed. The srandom function,
   unlike the srand function, does not return the old seed because
   the amount of state information used is more than a single word.

   See also rand, srand, srandom, setstate, and initstate.
 

3  Return_Value

   n                  A random number.
 

2  [no]raw
   Raw mode only works with the Curses input routines [w]getch
   and [w]getstr. Raw mode is not supported with the Compaq C RTL
   emulation of UNIX I/O, Terminal I/O, or Standard I/O.

   Format

     #include  <curses.h>

     raw()

     noraw()
 

3  Description
   Raw mode reads are satisfied on one of two conditions: after
   a minimum number (5) of characters are input at the terminal
   or after waiting a fixed time (10 seconds) from receipt of any
   characters from the terminal.
 

3  Example

       /* Example of standard and raw input in Curses package. */

       #include <curses.h>

       main()
       {
           WINDOW *win1;
           char vert = '.',
                hor = '.',
                str[80];

           /* Initialize standard screen, turn echo off.  */

           initscr();
           noecho();

           /* Define a user window.  */

           win1 = newwin(22, 78, 1, 1);
           leaveok(win1, TRUE);
           leaveok(stdscr, TRUE);

           box(stdscr, vert, hor);

           /* Reset the video, refresh(redraw) both windows. */

           mvwaddstr(win1, 2, 2, "Test line terminated input");
           wrefresh(win1);

           /* Do some input and output it. */
           nocrmode();
           wgetstr(win1, str);

           mvwaddstr(win1, 5, 5, str);
           mvwaddstr(win1, 7, 7, "Type something to clear screen");
           wrefresh(win1);

           /* Get another character then delete the window. */

           wgetch(win1);
           wclear(win1);

           mvwaddstr(win1, 2, 2, "Test raw input");
           wrefresh(win1);

           /* Do some raw input 5 chars or timeout and output it. */
           raw();
           getstr(str);
           noraw();
           mvwaddstr(win1, 5, 5, str);
           mvwaddstr(win1, 7, 7, "Raw input completed");
           wrefresh(win1);

           endwin();
       }
 

2  read
   Reads bytes from a file and places them in a buffer.

   Format

     #include  <unistd.h>

     ssize_t read  (int file_desc, void *buffer, size_t nbytes);
                   (ISO POSIX-1)

     int read  (int file_desc, void *buffer, int nbytes);       
               (Compatibility)
 

3  Arguments
 

file_desc

   A file descriptor. The specified file descriptor must refer to a
   file currently opened for reading.
 

buffer

   The address of contiguous storage in which the input data is
   placed.
 

nbytes

   The maximum number of bytes involved in the read operation.
 

3  Description
   The read function returns the number of bytes read. The return
   value does not necessarily equal nbytes. For example, if the
   input is from a terminal, at most one line of characters is read.

                                  NOTE

      The read function does not span record boundaries in a
      record file and, therefore, reads at most one record. A
      separate read must be done for each record.
 

3  Return_Values

   n                  The number of bytes read.
   -1                 Indicates a read error, including physical
                      input errors, illegal buffer addresses,
                      protection violations, undefined file
                      descriptors, and so forth.
 

3  Example

       #include <unistd.h>
       #include <stdlib.h>
       #include <stdio.h>
       #include <fcntl.h>

       main()
       {
           int fd,
               i;
           char buf[10];
           FILE *fp ;          /* Temporary STDIO file */

           /* Create a dummy data file  */

           if ((fp = fopen("test.txt", "w+")) == NULL) {
               perror("open");
               exit(1);
           }
           fputs("XYZ\n",fp) ;
           fclose(fp) ;

           /* And now practice "read" */

           if ((fd = open("test.txt", O_RDWR, 0, "shr=upd")) <= 0) {
               perror("open");
               exit(0);
           }

           /* Read 2 characters into buf.  */

           if ((i = read(fd, buf, 2)) < 0) {
               perror("read");
               exit(0);
           }

           /* Print out what was read.  */

           if (i > 0)
               printf("buf='%c%c'\n", buf[0], buf[1]);

           close(fd);
       }
 

2  readdir
   Finds entries in a directory.

   Format

     #include  <dirent.h>

     struct dirent *readdir  (DIR *dir_pointer);

     int readdir_r  (DIR *dir_pointer, struct dirent *entry, struct
                    dirent **result);
 

3  Arguments
 

dir_pointer

   A pointer to the dir structure of an open directory.
 

entry

   A pointer to a dirent structure that will be initialized with the
   directory entry at the current position of the specified stream.
 

result

   Upon successful completion, the location where a pointer to entry
   is stored.
 

3  Description
   The readdir function returns a pointer to a structure
   representing the directory entry at the current position in the
   directory stream specified by dir_pointer, and positions the
   directory stream at the next entry. It returns a NULL pointer
   upon reaching the end of the directory stream. The dirent
   structure defined in the <dirent.h> header file describes a
   directory entry.

   The type DIR defined in the <dirent.h> header file represents a
   directory stream. A directory stream is an ordered sequence of
   all the directory entries in a particular directory. Directory
   entries represent files. You can remove files from or add files
   to a directory asynchronously to the operation of the readdir
   function.

   The pointer returned by the readdir function points to data
   that you can overwrite by another call to readdir on the same
   directory stream. This data is not overwritten by another call to
   readdir on a different directory stream.

   If a file is removed from or added to the directory after
   the most recent call to the opendir or rewinddir function, a
   subsequent call to the readdir function might not return an entry
   for that file.

   When it reaches the end of the directory, or when it detects an
   invalid seekdir operation, the readdir function returns the null
   value.

   An attempt to seek to an invalid location causes the readdir
   function to return the null value the next time it is called. A
   previous telldir function call returns the position.

   The readdir_r function is a reentrant version of readdir. In
   addition to dir_pointer, you must specify a pointer to a dirent
   structure in which the current directory entry of the specified
   stream is returned.

   If the operation is successful, readdir_r returns 0 and stores
   one of the following two pointers in result:

   o  Pointer to entry if the entry was found

   o  NULL pointer if the end of the directory stream was reached

   The storage pointed to by entry must be large enough for a dirent
   with an array of char d_name member containing at least NAME_MAX
   + 1 elements.

   If an error occurred, an error value is returned that indicates
   the cause of the error.

   Applications wishing to check for error situations should set
   errno to 0 before calling readdir. If errno is set to nonzero on
   return, then an error occurred.
 

3  Example

     See the description of closedir for an example.
 

3  Return_Values

   x                  On successful completion of readdir, a pointer
                      to an object of type struct dirent.
   0                  Successful completion of readdir_r.
   x                  On error, an error value (readdir_r only).
   NULL               An error occurred or end of the directory
                      stream (readdir_r only). If an error occurred,
                      errno is set to a value indicating the cause.
 

2  readlink
   Reads the contents of the specified symbolic link and places them
   into a user-supplied buffer.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     ssize_t readlink  (const char *restrict link_name, char       
                       *restrict user_buffer, size_t buffer_size);
 

3  Arguments
 

link_name

   Pointer to the text string representing the name of the symbolic
   link file.
 

user_buffer

   Pointer to the user buffer.
 

buffer_size

   Size of the user buffer.
 

3  Description
   The readlink function reads the contents of the specified
   symbolic link (link_name) and places them into a user-supplied
   buffer (user_buffer) of size (buffer_size).

   See also symlink, unlink, realpath, lchown, and lstat.
 

3  Return_Values

   n                  Upon successful completion, the count of bytes
                      placed in the user_buffer
   -1                 Indicates an error. The buffer is unchanged,
                      and errno is set to indicate the error:

                      o  EACCES - Read permission is denied in the
                         directory where the symbolic link is being
                         read, or search permission is denied for a
                         component of the path prefix of link_name.

                      o  ENAMETOOLONG - The length of the link_name
                         argument exceeds PATH_MAX, or a pathname
                         component is longer than NAME_MAX.

                      o  Any errno value from close, open, or read.
 

2  readv
   Reads from a file.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <sys/uio.h>

     ssize_t readv  (int file_desc, const struct iovec *iov, int iovcnt);

     ssize_t _readv64  (int file_desc, struct __iovec64 *iov, int iovcnt);
 

3  Function_Variants
   The readv function has variants named _readv32 and _readv64 for
   use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

file_desc

   A file descriptor. A file descriptor that must refer to a file
   currently opened for reading.
 

iov

   Array of iovec structures into which the input data is placed.
 

iovcnt

   The number of buffers specified by the members of the iov array.
 

3  Description
   The readv function is equivalent to read, but places the input
   data into the iovcnt buffers specified by the members of the iov
   array: iov[0], iov[1], ..., iov[iovcnt-1]. The iovcnt argument is
   valid if it is greater than 0 and less than or equal to IOV_MAX.

   Each iovec entry specifies the base address and length of an area
   in memory where data should be placed. The readv function always
   fills an area completely before proceeding to the next.

   Upon successful completion, readv marks for update the st_atime
   field of the file.

   If the Synchronized Input and Output option is supported:

         If the O_DSYNC and O_RSYNC bits have been set, read
         I/O operations on the file descriptor will complete
         as defined by synchronized I/O data integrity
         completion.

         If the O_SYNC and O_RSYNC bits have been set, read
         I/O operations on the file descriptor will complete
         as defined by synchronized I/O file integrity
         completion.

   If the Shared Memory Objects option is supported:

         If file_desc refers to a shared memory object, the
         result of the read function is unspecified.

   For regular files, no data transfer occurs past the offset
   maximum established in the open file description associated with
   file_desc.
 

3  Return_Values

   n                  The number of bytes read.
   -1                 Indicates a read error. The function sets
                      errno to one of the following values:

                      o  EAGAIN - The O_NONBLOCK flag is set for the
                         file descriptor, and the process would be
                         delayed.

                      o  EBADF - The file_desc argument is not a
                         valid file descriptor open for reading.

                      o  EBADMSG - The file is a STREAM file that is
                         set to control-normal mode, and the message
                         waiting to be read includes a control part.

                      o  EINTER - The read operation was terminated
                         because of the receipt of a signal, and no
                         data was transferred.

                      o  EINVAL - The STREAM or multiplexer
                         referenced by file_desc is linked
                         (directly or indirectly) downstream from
                         a multiplexer.

                         OR

                         The sum of the iov_len values in the iov
                         array overflowed an ssize_t.

                      o  EIO - A physical I/O error has occurred.

                         OR

                         The process is a member of a background
                         process attempting to read from its
                         controlling terminal, the process is
                         ignoring or blocking the SIGTTIN signal,
                         or the process group is orphaned.

                      o  EISDIR - The file_desc argument refers to a
                         directory, and the implementation does not
                         allow the directory to be read using read,
                         pread or readv. Use the readdir function
                         instead.

                      o  EOVERFLOW - The file is a regular file,
                         nbyte is greater than 0, and the starting
                         position is before the end-of-file and is
                         greater than or equal to the offset maximum
                         established in the open file description
                         associated with file_desc.

                      The readv function may fail if:

                      o  EINVAL - The iovcnt argument was less than
                         or equal to 0, or greater than IOV_MAX.
 

2  realloc
   Changes the size of the area pointed to by the first argument to
   the number of bytes given by the second argument. These functions
   are AST-reentrant.

   Format

     #include  <stdlib.h>

     void *realloc  (void *ptr, size_t size);
 

3  Function_Variants
   The realloc function has variants named _realloc32 and _realloc64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

ptr

   Points to an allocated area, or can be NULL.
 

size

   The new size of the allocated area.
 

3  Description
   If ptr is the NULL pointer, the behavior of the realloc function
   is identical to the malloc function.

   The contents of the area are unchanged up to the lesser of the
   old and new sizes. The ANSI C Standard states that, "If the
   new size is larger than the old size, the value of the newly
   allocated portion of memory is indeterminate." For compatibility
   with old implementations, Compaq C initializes the newly
   allocated memory to 0.

   For efficiency, the previous actual allocation could have been
   larger than the requested size. If it was allocated with malloc,
   the value of the portion of memory between the previous requested
   allocation and the actual allocation is indeterminate. If it was
   allocated with calloc, that same memory was initialized to 0. If
   your application relies on realloc initializing memory to 0, then
   use calloc instead of malloc to perform the initial allocation.
   The maximum amount of memory allocated at once is limited to
   0xFFFFD000.

   See also free, cfree, calloc, and malloc.
 

3  Return_Values

   x                  The address of the area, quadword-
                      aligned (Alpha only) or octaword-aligned
                      (Integrity servers(ONLY)) . The address is
                      returned because the area may have to be moved
                      to a new address to reallocate enough space.
                      If the area was moved, the space previously
                      occupied is freed.
   NULL               Indicates that space cannot be reallocated
                      (for example, if there is not enough room).
 

2  realpath
   Returns an absolute pathname from the POSIX root.

   Format

     #include  <stdlib.h>

     char realpath  (const char *restrict file_name, char *restrict 
                    resolved_name);
 

3  Arguments
 

file_name

   Pointer to the text string representing the name of the file for
   which you want the absolute path.
 

resolved name

   Pointer to the generated absolute path stored as a null-
   terminated string.
 

3  Description
   The realpath function returns an absolute pathname from the
   POSIX root. The generated pathname is stored as a null-terminated
   string, up to a maximum of PATH_MAX bytes, in the buffer pointed
   to by resolved_name.

   The realpath function is supported only in POSIX-compliant modes
   (that is, with DECC$POSIX_COMPLIANT_PATHNAMES defined to one of
   the allowed values).

   See also symlink, unlink, readlink, lchown, and lstat.
 

3  Return_Values

   x                  Upon successful completion, a pointer to the
                      resolved_name.
   NULL               Indicates an error. A null pointer is
                      returned, the contents of the buffer pointed
                      to by resolved_name are undefined, and errno
                      is set to indicate the error:

                      o  ENAMETOOLONG - The length of the file_name
                         argument exceeds PATH_MAX, or a pathname
                         component is longer than NAME_MAX.

                      o  ENOENT - A component of file_name does not
                         name an existing file, or file_name points
                         to an empty string.

                      o  Any errno value from chdir or stat.
 

2  [w]refresh
   Repaint the specified window on the terminal screen. The refresh
   function acts on the stdscr window.

   Format

     #include  <curses.h>

     int refresh();

     int wrefresh  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Description
   The result of this process is that the portion of the window not
   occluded by subwindows or other windows appears on the terminal
   screen. To see the entire occluded window on the terminal screen,
   call the touchwin function instead of the refresh or wrefresh
   function.

   See also touchwin.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  remainder
   Returns the floating-point remainder r = x - n*y) when y is
   nonzero.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double remainder  (double x, double y);

     float remainderf  (float x, float y);

     long double remainderl  (long double x, long double y);
 

3  Argument
 

x

   A real number.
 

y

   A real number.
 

3  Description
   These functions return the floating-point remainder r = x - n*y)
   when y is nonzero. The value n is the integral value nearest the
   exact value x/y. That is, n = rint(x/y).

   When |n - x/y| = 1/2, the value n is chosen to be even.

   The behavior of the remainder function is independent of the
   rounding mode.

   The remainder functions are functionally equivalent to the remquo
   functions.
 

3  Return_Values

   r                  Upon successful completion, these functions
                      return the floating-point remainder r = x - ny
                      when y is nonzero.
   Nan                If x or y is Nan.
 

2  remquo
   Returns the floating-point remainder r = x - n*y) when y is
   nonzero.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double remquo  (double x, double y, int * quo);

     float remquof  (float x, float y, int * quo);

     long double remquol  (long double x, long double y, int * quo);
 

3  Argument
 

x

   A real number.
 

y

   A real number.
 

quo
 

3  Description
   The remquo(), remquof(),  and remquol() functions compute
   the same remainder as the remainder(), remainderf(),  and
   remainderl() functions, respectively. In the object pointed to
   by quo, they store a value whose sign is the sign of x/y and
   whose magnitude is congruent modulo 2n to the magnitude of the
   integral quotient of x/y, where n is an implementation-defined
   integer greater than or equal to 3.

   The remquo functions are functionally equivalent to the remainder
   functions.
 

3  Return_Values

   r                  Upon successful completion, these functions
                      return the floating-point remainder r = x - ny
                      when y is nonzero.
   Nan                If x or y is Nan.
 

2  remove
   Deletes a file.

   Format

     #include  <stdio.h>

     int remove  (const char *file_spec);
 

3  Argument
 

file_spec

   A pointer to the string that is an OpenVMS or a UNIX style file
   specification. The file specification can include a wildcard
   in its version number. So, for example, files of the form
   filename.txt;* can be deleted.
 

3  Description
   If you specify a directory in the filename and it is a search
   list that contains an error, Compaq C for OpenVMS Systems
   interprets it as a file error.

                                  NOTE

      The DECC$ALLOW_REMOVE_OPEN_FILES feature logical controls
      the behavior of the remove function on open files.
      Ordinarily, the operation fails. However, POSIX conformance
      dictates that the operation succeed.

      With DECC$ALLOW_REMOVE_OPEN_FILES enabled, this POSIX
      conformant behavior is achieved.

   When remove is used to delete a symbolic link, the link itself is
   deleted, not the file to which it refers.

   The remove and delete functions are functionally equivalent in
   the Compaq C RTL.

   See also delete.
 

3  Return_Values

   0                  Indicates success.
   nonzero value      Indicates failure.
 

2  rename
   Gives a new name to an existing file.

   Format

     #include  <stdio.h>

     int rename  (const char *old_file_spec, const char             
                 *new_file_spec);
 

3  Arguments
 

old_file_spec

   A pointer to a string that is the existing name of the file to be
   renamed.
 

new_file_spec

   A pointer to a string that is to be the new name of the file.
 

3  Description
   If you try to rename a file that is currently open, the behavior
   is undefined. You cannot rename a file from one physical device
   to another. Both the old and new file specifications must reside
   on the same device.

   If the new_file_spec does not contain a file extension, the
   file extension of old_file_spec is used. To rename a file to
   have no file extension, new_file_spec must contain a period
   (.)  For example, the following renames SYS$DISK:[]FILE.DAT to
   SYS$DISK:[]FILE1.DAT:

   rename("file.dat", "file1");

   However, the following renames SYS$DISK:[]FILE.DAT to
   SYS$DISK:[]FILE1:

   rename("file.dat", "file1.");

                                  NOTE

      Because the rename function does special processing of the
      file extension, the caller must be careful when specifying
      the name of the renamed file in a call to a C Run-Time
      Library function that accepts a file-name argument. For
      example, after the following call to the rename function,
      the new file should be opened as fopen("bar.dat",...):

      rename("foo.dat", "bar");

   The rename function is affected by the setting of the
   DECC$RENAME_NO_INHERIT and DECC$RENAME_ALLOW_DIR feature logicals
   as follows:

   o  DECC$RENAME_NO_INHERIT provides more UNIX compliant behavior
      in rename, and affects whether or not the new name for the
      file inherits anything (like file type) from the old name or
      must be specified completely.

   o  DECC$RENAME_ALLOW_DIR lets you choose between the previous
      OpenVMS behavior of allowing the renaming of a file from one
      directory to another, or the more UNIX compliant behavior of
      not allowing the renaming of a file to a directory.

   Also see the C RTL help for feature logicals DECC$RENAME_NO_
   INHERIT and DECC$RENAME_ALLOW_DIR.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates failure. The function sets errno to
                      one of the following values:

                      o  EISDIR - The new argument points to a
                         directory, and the old argument points
                         to a file that is not a directory.

                      o  EEXIST - The new argument points to a
                         directory that already exists.

                      o  ENOTDIR - The old argument names a
                         directory, and new argument names a non-
                         directory file.

                      o  ENOENT - The old argument points to a file,
                         directory, or device that does not exist.

                         Or the new argument points to a nonexisting
                         directory path or device.
 

2  rewind
   Sets the file to its beginning.

   Format

     #include  <stdio.h>

     void rewind  (FILE *file_ptr); (ISO POSIX-1)

     int rewind  (FILE *file_ptr); (DEC C Extension)
 

3  Argument
 

file_ptr

   A file pointer.
 

3  Description
   The rewind function is equivalent to fseek (file_ptr, 0, SEEK_
   SET). You can use the rewind function with either record or
   stream files.

   A successful call to rewind clears the error indicator for the
   file.

   The ANSI C standard defines rewind as not returning a value;
   therefore, the function prototype for rewind is declared with a
   return type of void. However, since a rewind can fail, and since
   previous versions of the Compaq C RTL have declared rewind to
   return an int, the code for rewind does return 0 on success and
   -1 on failure.

   See also fseek.
 

2  rewinddir
   Resets the position of the specified directory stream to the
   beginning of a directory.

   Format

     #include  <dirent.h>

     void rewinddir  (DIR *dir_pointer);
 

3  Argument
 

dir_pointer

   A pointer to the dir structure of an open directory.
 

3  Description
   The rewinddir function resets the position of the specified
   directory stream to the beginning of the directory. It also
   causes the directory stream to refer to the current state of the
   corresponding directory, the same as using the opendir function.
   If the dir_pointer argument does not refer to a directory stream,
   the effect is undefined.

   The type DIR, defined in the <dirent.h> header file, represents
   a directory stream. A directory stream is an ordered sequence of
   all the directory entries in a particular directory. Directory
   entries represent files.

   See also opendir.
 

2  rindex
   Searches for a character in a string.

   Format

     #include  <strings.h>

     char *rindex  (const char *s, int c);
 

3  Function_Variants
   The rindex function has variants named _rindex32 and _rindex64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

s

   The string to search.
 

c

   The character to search for.
 

3  Description
   The rindex function is identical to the strchr function, and is
   provided for compatibility with some UNIX implementations.
 

2  rint
   Rounds its argument to an integral value according to the current
   IEEE rounding direction specified by the user.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double rint  (double x);

     float rintf  (float x,);

     long double rintl  (long double x);
 

3  Argument
 

x

   A real number.
 

3  Description
   The rint functions return the nearest integral value to x in
   the direction of the current IEEE rounding mode specified on the
   /ROUNDING_MODE command-line qualifier.

   If the current rounding mode rounds toward negative Infinity,
   then rint is identical to floor. If the current rounding mode
   rounds toward positive Infinity, then rint is identical to ceil.

   If |x| = Infinity, rint returns x.
 

3  Return_Values

   n                  The nearest integral value to x in the
                      direction of the current IEEE rounding mode.
   NaN                x is NaN; errno is set to EDOM.
 

2  rmdir
   Removes a directory file.

   Format

     #include  <unistd.h>

     int rmdir  (const char *path);
 

3  Argument
 

path

   A directory pathname.
 

3  Description
   The rmdir function removes a directory file whose name is
   specified in the path argument. The directory is removed only
   if it is empty.

   If path names a symbolic link, then rmdir fails and sets errno to
   ENOTDIR.
 

3  Restriction
   When using OpenVMS format names, the path argument must be in the
   form directory.dir.
 

3  Return_Values

   0                  Indicates success.
   -1                 An error occurred; errno is set to indicate
                      the error.
 

2  sbrk
   Determines the lowest virtual address that is not used with the
   program.

   Format

     #include  <unistd.h>

     void *sbrk  (long int incr);
 

3  Argument
 

incr

   The number of bytes to add to the current break address.
 

3  Description
   The sbrk function adds the number of bytes specified by its
   argument to the current break address and returns the old break
   address.

   When a program is executed, the break address is set to the
   highest location defined by the program and data storage areas.
   Consequently, sbrk is needed only by programs that have growing
   data areas.

   sbrk(0) returns the current break address.
 

3  Return_Values

   x                  The old break address.
   (void *)(-1)       Indicates that the program is requesting too
                      much memory.
 

3  Restriction
   Unlike other C library implementations, the Compaq C RTL memory
   allocation functions (such as malloc) do not rely on brk or
   sbrk to manage the program heap space. Consequently, on OpenVMS
   systems, calling brk or sbrk can interfere with memory allocation
   routines. The brk and sbrk functions are provided only for
   compatibility purposes.
 

2  scalb
   Returns the exponent of a floating-point number.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double scalb  (double x, double n);

     float scalbf  (float x, float n);

     long double scalbl  (long double x, long double n);
 

3  Arguments
 

x

   A nonzero floating-point number.
 

n

   An integer.
 

3  Description
   The scalb functions return x*(2**n) for integer n.
 

3  Return_Values

   x                  On successful completion, x*(2**n) is
                      returned.
   HUGE_VAL           On overflow, scalb returns HUGE_VAL (according
                      to the sign of x) and sets errno to ERANGE.
   0                  Underflow occurred; errno is set to ERANGE.
   x                  x is Infinity.
   NaN                x or n is NaN; errno is set to EDOM.
 

2  scanf
   Performs formatted input from the standard input (stdin),
   interpreting it according to the format specification.

   Format

     #include  <stdio.h>

     int scanf  (const char *format_spec, . . . );
 

3  Arguments
 

format_spec

   Pointer to a string containing the format specification. The
   format specification consists of characters to be taken literally
   from the input or converted and placed in memory at the specified
   input sources.
 

 . . .

   Optional expressions that are pointers to objects whose resultant
   types correspond to conversion specifications given in the format
   specification.

   If no conversion specifications are given, you can omit these
   input pointers. Otherwise, the function call must have at least
   as many input pointers as there are conversion specifications,
   and the conversion specifications must match the types of the
   input pointers.

   Conversion specifications are matched to input sources in left-
   to-right order. Excess input pointers, if any, are ignored.
 

3  Return_Values

   x                  The number of successfully matched and
                      assigned input items.
   EOF                Indicates that a read error occurred prior to
                      any successful conversions. The function sets
                      errno. For a list of errno values set by this
                      function, see fscanf.
 

2  [w]scanw
   Perform a scanf on the window. The scanw function acts on the
   stdscr window.

   Format

     #include  <curses.h>

     int scanw  (char *format_spec, . . . );

     int wscanw  (WINDOW *win, char *format_spec, . . . );
 

3  Arguments
 

win

   A pointer to the window.
 

format_spec

   A pointer to the format specification string.
 

 . . .

   Optional expressions that are pointers to objects whose resultant
   types correspond to conversion specifications given in the format
   specification. If no conversion specifications are given, you may
   omit these input pointers.

   Otherwise, the function call must have at least as many input
   pointers as there are conversion specifications, and the
   conversion specifications must match the types of the input
   pointers.

   Conversion specifications are matched to input sources in left-
   to-right order. Excess input pointers, if any, are ignored.
 

3  Description
   The formatting specification (format_spec) and the other
   arguments are identical to those used with the scanf function.

   The scanw and wscanw functions accept, format, and return a line
   of text from the terminal screen. For more information, see the
   scrollok and scanf functions.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates that the function makes the
                      screen scroll illegally or that the scan was
                      unsuccessful.
 

2  scroll
   Moves all the lines on the window up one line. The top line
   scrolls off the window and the bottom line becomes blank.

   Format

     #include  <curses.h>

     int scroll  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  scrollok
   Sets the scroll flag for the specified window.

   Format

     #include  <curses.h>

     scrollok  (WINDOW *win, bool boolf);
 

3  Arguments
 

win

   A pointer to the window.
 

boolf

   A Boolean TRUE or FALSE value. If boolf is FALSE, scrolling
   is not allowed. This is the default setting. The bool type is
   defined in the <curses.h> header file as follows:

   #define bool int
 

2  seed48
   Initializes a 48-bit random-number generator.

   Format

     #include  <stdlib.h>

     unsigned short *seed48  (unsigned short seed_16v[3]);
 

3  Argument
 

seed_16v

   An array of three unsigned short ints that form a 48-bit seed
   value.
 

3  Description
   The seed48 function initializes the random-number generator.
   You can use this function in your program before calling the
   drand48, lrand48, or mrand48 functions. (Although it is not
   recommended practice, constant default initializer values are
   supplied automatically if you call drand48, lrand48, or mrand48
   without calling an initialization function).

   The seed48 function works by generating a sequence of 48-bit
   integer values, Xi, according to the linear congruential formula:

          Xn+1 = (aXn+c)mod m        n > 0

   The argument m equals 248, so 48-bit integer arithmetic is

   performed. Unless you invoke the lcong48 function, the multiplier
   value a and the addend value c are:

         a = 5DEECE66D16 = 2736731631558

         c = B16 = 138

   The initializer function seed48:

   o  Sets the value of Xi to the 48-bit value specified in the
      array pointed to by seed_16v.

   o  Returns a pointer to a 48-bit internal buffer that contains
      the previous value of Xi, used only by seed48.

   The returned pointer allows you to restart the pseudorandom
   sequence at a given point. Use the pointer to copy the previous
   Xi value into a temporary array. To resume where the original
   sequence left off, you can call seed48 with a pointer to this
   array.

   See also drand48, lrand48, and mrand48.
 

3  Return_Value

   x                  A pointer to a 48-bit internal buffer.
 

2  seekdir
   Sets the position of a directory stream.

   Format

     #include  <dirent.h>

     void seekdir  (DIR *dir_pointer, long int location);
 

3  Arguments
 

dir_pointer

   A pointer to the dir structure of an open directory.
 

location

   The number of an entry relative to the start of the directory.
 

3  Description
   The seekdir function sets the position of the next readdir
   operation on the directory stream specified by dir_pointer to
   the position specified by location. The value of location should
   be returned from an earlier call to telldir.

   If the value of location was not returned by a call to the
   telldir function, or if there was an intervening call to the
   rewinddir function on this directory stream, the effect is
   unspecified.

   The type DIR, defined in the <dirent.h> header file, represents
   a directory stream. A directory stream is an ordered sequence of
   all the directory entries in a particular directory. Directory
   entries represent files. You can remove files from or add files
   to a directory asynchronously to the operation of the readdir
   function.

   See readdir, rewinddir, and telldir.
 

2  sem_close
   Deallocates the specified named semaphore.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <semaphore.h>

     int sem_close  (sem_t *sem);
 

3  Argument
 

sem

   The semaphore to be closed. Use the sem argument returned by the
   previous call to sem_open.
 

3  Description
   The sem_close function makes a semaphore available for reuse
   by deallocating any system resources allocated for use by the
   current process for the named semaphore indicated by sem.

   If the semaphore has not been removed with a call to sem_unlink,
   sem_close does not change the current state of the semaphore.

   If the semaphore has been removed with a call to sem_unlink after
   the most recent call to sem_open with O_CREAT, the semaphore is
   no longer available after all processes that opened the semaphore
   close it.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EINVAL - The sem argument is not a valid
                         semaphore descriptor.

                      o  ENOSYS - The function is not implemented.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  semctl
   Semaphore control operations

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <sem.h>

     int semctl  (int semid, int semnum, int cmd, . . . );
 

3  Argument
 

semid

   A semaphore set identifier, a positive integer. It is created
   by the semget function and used to identify the semaphore set on
   which to perform the control operation.
 

semnum

   Semaphore number, a non-negative integer. It identifies a
   semaphore within the semaphore set on which to perform the
   control operation.
 

cmd

   The control operation to perform on the semaphore.
 

 . . .

   Optional fourth argument of type union semun, which depends on
   the control operation requested in cmd.
 

3  Description
   The semctl function provides a variety of semaphore control
   operations as specified by cmd. The fourth argument is optional
   and depends upon the operation requested. If required, it is of
   type union semun, which is explicitly declared as:

   union semun {
       int val;
       struct semid_ds *buf;
       unsigned short  *array;
   } arg;

   The following semaphore control operations as specified by cmd
   are executed with respect to the semaphore specified by semid and
   semnum. The level of permission required for each operation is
   shown with each command. The symbolic names for the values of cmd
   are defined in the <sem.h> header:

   o  GETVAL

      Returns the value of semval. Requires read permission.

   o  SETVAL

      Sets the value of semval to arg.val, where arg is the value
      of the fourth argument to semctl. When this command is
      successfully executed, the semadj value corresponding to the
      specified semaphore in all processes is cleared. Requires
      alter permission.

   o  GETPID

      Returns the value of sempid; requires read permission.
 

   o  GETNCNT

      Returns the value of semncnt; requires read permission.

   o  GETZCNT

      Returns the value of semzcnt; requires read permission.

   The following values of cmd operate on each semval in the set of
   semaphores:

   o  GETALL

      Returns the value of semval for each semaphore in the
      semaphore set and places it into the array pointed to by
      arg.array, where arg is the fourth argument to semctl;
      requires read permission.

   o  SETALL

      Sets the value of semval for each semaphore in the semaphore
      set according to the array pointed to by arg.array, where
      arg is the fourth argument to semctl. When this command is
      successfully executed, the semadj values corresponding to each
      specified semaphore in all processes are cleared. Requires
      alter permission.

   The following values of cmd are also available:

   o  IPC_STAT

      Places the current value of each member of the semid_ds data
      structure associated with semid into the structure pointed to
      by arg.buf, where arg is the fourth argument to semctl. The
      contents of this structure are defined in <sem.h>. Requires
      read permission.

   o  IPC_SET

      Sets the value of the following members of the semid_ds data
      structure associated with semid to the corresponding value
      found in the structure pointed to by arg.buf, where arg is the
      fourth argument to semctl:

      sem_perm.uid
      sem_perm.gid
      sem_perm.mode

      The mode bits specified in The Open Group Base Specifications
      IPC General Description section are copied into the
      corresponding bits of the sem_perm.mode associated with semid.
      The stored values of any other bits are unspecified.

      This command can only be executed by a process that has an
      effective user ID equal to either that of a process with
      appropriate privileges or to the value of sem_perm.cuid or
      sem_perm.uid in the semid_ds data structure associated with
      semid.

   o  IPC_RMID

      Removes the semaphore identifier specified by semid from
      the system and destroys the set of semaphores and semid_ds
      data structure associated with it. This command can only be
      executed by a process that has an effective user ID equal to
      either that of a process with appropriate privileges or to the
      value of sem_perm.cuid or sem_perm.uid in the semid_ds data
      structure associated with semid.
 

3  Return_Values

   n or 0             Upon successful completion, the value returned
                      by the function depends on cmd as follows:

                      o  GETVAL - The value of semval

                      o  GETPID - The value of sempid

                      o  GETNCNT - The value of semncnt

                      o  GETZCNT - The value of semzcnt

                      o  All others - 0

   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EACCES - Operation permission is denied to
                         the calling process.

                      o  EFAULT - The arguments passed to the
                         function are not accessible.

                      o  EINVAL - The value of semid is not a valid
                         semaphore identifier, or the value of
                         semnum is less than zero or greater than
                         or equal to sem_nsems, or the value of cmd
                         is not a valid command.

                      o  EPERM - The argument cmd is equal to IPC_
                         RMID or IPC_SET and the effective user ID
                         of the calling process is not equal to that
                         of a process with appropriate privileges
                         and it is not equal to the value of sem_
                         perm.cuid or sem_perm.uid in the data
                         structure associated with semid.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  sem_destroy
   Destroys an unnamed semaphore.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <semaphore.h>

     int sem_destroy  (sem_t *sem);
 

3  Argument
 

sem

   The unnamed semaphore to be destroyed. Use the sem argument that
   was supplied to, and filled in by, the previous call to sem_init.
 

3  Description
   The sem_destroy function destroys an unnamed semaphore indicated
   by sem. Only a semaphore created using sem_init may be destroyed
   using sem_destroy.

   The potential for deadlock exists if a process calls sem_destroy
   for a semaphore while there is a pending sem_wait, because a
   process may be waiting for a poster that has not yet opened the
   semaphore.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno
                      to one of the following values, without
                      destroying the semaphore indicated by the
                      sem argument:

                      o  EINVAL - The sem argument is not a valid
                         semaphore.

                      o  ENOSYS - The function is not implemented.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.

                      o  EBUSY - The processes are blocked on the
                         semaphore.
 

2  semget
   Gets a set of semaphores.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <sem.h>

     int semget  (key_t key, int nsems, int semflg);
 

3  Argument
 

key

   The key for which the associated semaphore identifier is
   returned.
 

nsems

   Value used to initialize the sem_nsems member of the semid_ds
   data structure. See the description.
 

semflg

   Flag used to initialize the low-order 9 bits of the sem_perm.mode
   member of the semid_ds data structure associated with the new
   semaphore. See the description.
 

value

   The initial value to be given to the semaphore. This argument is
   used only when the semaphore is being created.
 

3  Description
   The semget function returns the semaphore identifier associated
   with key.

   A semaphore identifier with its associated semid_ds data
   structure and its associated set of nsems semaphores (see
   the <sys/sem.h> header file) is created for key if one of the
   following is true:

   o  The key argument is equal to IPC_PRIVATE.

   o  The key argument does not already have a semaphore identifier
      associated with it and (semflg &IPC_CREAT) is nonzero.

   When it is created, the semid_ds data structure associated with
   the new semaphore identifier is initialized as follows:

   o  In the operation permissions structure sem_perm.cuid, sem_
      perm.uid, sem_perm.cgid, and sem_perm.gid are set equal to the
      effective user ID and effective group ID, respectively, of the
      calling process.

   o  The low-order 9 bits of sem_perm.mode are set equal to the
      low-order 9 bits of the semflg argument.

   o  The variable sem_nsems is set equal to the value of the nsems
      argument.

   o  The variable sem_otime is set equal to 0 and the variable sem_
      ctime is set equal to the current time.

   o  The data structure associated with each semaphore in the
      set does not need to be initialized. You can use the semctl
      function with the command SETVAL or SETALL to initialize each
      semaphore.
 

3  Return_Values

   n                  Successful completion. The function returns a
                      non-negative integer semaphore identifier.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EACCES - A semaphore identifier exists for
                         key, but operation permission as specified
                         by the low-order 9 bits of semflg was not
                         granted.

                      o  EEXIST - A semaphore identifier exists
                         for key but ((semflg &IPC_CREAT) &&(semflg
                         &IPC_EXCL)) is nonzero.

                      o  EFAULT - The arguments passed to the
                         function are not accessible.

                      o  EINVAL - The value of nsems is either
                         less than or equal to 0 or greater than
                         the system-imposed limit, or a semaphore
                         identifier exists for key, but the number
                         of semaphores in the set associated with it
                         is less than nsems and nsems is not equal
                         to 0.

                      o  ENOENT - A semaphore identifier does not
                         exist for key and (semflg &IPC_CREAT) is
                         equal to 0.

                      o  ENOSPC - A semaphore identifier is to be
                         created but the system-imposed limit on
                         the maximum number of allowed semaphores
                         system-wide will be exceeded.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  sem_getvalue
   Gets the value of a specified semaphore.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <semaphore.h>

     int sem_getvalue  (sem_t *sem, int *sval);
 

3  Argument
 

sem

   The semaphore for which a value is to be returned.
 

sval

   The location to be updated with the value of the semaphore
   indicated by the sem argument.
 

3  Description
   The sem_getvalue function updates a location referenced by the
   sval argument with the value of semaphore sem. The updated value
   represents an actual semaphore value that occurred during the
   call, but may not be the actual value of the semaphore at the
   time that the value is returned to the calling process.

   If the semaphore is locked, the value returned will either be
   zero or a negative number indicating the number of processes
   waiting for the semaphore at some time during the call.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EINVAL - The sem argument is not a valid
                         semaphore.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  sem_init
   Initializes an unnamed semaphore.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <semaphore.h>

     int sem_init  (sem_t *sem, int pshared, unsigned int value );
 

3  Argument
 

sem

   The location to receive the descriptor of the initialized
   semaphore.
 

pshared

   A value indicating whether the semaphore should be sharable
   between the creating process and its descendants (nonzero value)
   or not (zero).

                                  NOTE

      The value for pshared must be zero between threads because
      this release does not support unnamed semaphores to be
      shared across processes.
 

value

   The initial value to be given to the semaphore.
 

3  Description
   The sem_init function creates a new counting semaphore with a
   specific value. A semaphore is used to limit access to a critical
   resource. When a process requires access to the resource without
   interference from other processes, it attempts to establish
   a connection with the associated semaphore. If the semaphore
   value is greater than zero, the connection is established and the
   semaphore value is decremented by one. If the semaphore value is
   less than or equal to zero, the process attempting to access the
   resource is blocked and must wait for another process to release
   the semaphore and increment the semaphore value.

   The sem_init function establishes a connection between an
   unnamed semaphore and a process; the sem_wait and sem_trywait
   functions lock the semaphore; and the sem_post function unlocks
   the semaphore. Use the sem_destroy function to deallocate system
   resources allocated to the process for use with the semaphore.
   You can use the sem_getvalue function to obtain the value of a
   semaphore.

   A semaphore created by a call to the sem_init function remains
   valid until the semaphore is removed by a call to the sem_destroy
   function.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EINVAL - The value argument exceeds {SEM_
                         VALUE_MAX}.

                      o  ENOSYS - The function is not implemented.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  sem_open
   Opens/creates a named semaphore for use by a process.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <semaphore.h>

     sem_t *sem_open  (const char *name, int ooption...) ;
 

3  Argument
 

name

   a string naming the semaphore object.
 

ooption

   Specifies whether the semaphore is to be created (O_CREAT option
   bit set) or only opened (O_CREAT option bit clear). If O_CREAT is
   set, the O_EXCL option bit may additionally be set to specify
   that the call should fail if a semaphore of the same name
   already exists. The O_CREAT and O_EXCL options are defined in
   the <fcntl.h> header file.
 

mode

   The semaphore's permission bits. This argument is used only when
   the semaphore is being created.
 

value

   The initial value to be given to the semaphore. This argument is
   used only when the semaphore is being created.
 

3  Description
   Use the sem_open function to establish the connection between a
   named semaphore and a process. Subsequently, the calling process
   can reference the semaphore by using the address returned from
   the call. The semaphore is available in subsequent calls to sem_
   wait, sem_trywait, sem_post, and sem_getvalue functions. The
   semaphore remains usable by the process until the semaphore is
   closed by a successful call to the sem_close function.

   The O_CREAT option bit in the ooption parameter controls whether
   the semaphore is created or only opened by the call to sem_open.

   A created semaphore's user ID is set to the user ID of the
   calling process and its group ID is set to a system default group
   or to the group ID of the process. The semaphore's permission
   bits are set to the value of the mode argument, except for those
   set in the file mode creation mask of the process.

   After a semaphore is created, other processes can open the
   semaphore by calling sem_open with the same value for the name
   argument.
 

3  Return_Values

   sem                Successful completion. The function opens
                      the semaphore and returns the semaphore's
                      descriptor.
   sem_failed         Indicates an error. The function sets errno to
                      one of the following values:

                      o  EACCES-The named semaphore exists and
                         the permissions specified by ooption are
                         denied, or the named semaphore does not
                         exist and the permissions specified by
                         ooption are denied.

                      o  EEXIST-O_CREAT and O_EXCL are set, and the
                         named semaphore already exists.

                      o  EINVAL-The sem_open operation is not
                         supported for the given name. Or, O_CREAT
                         was specified in ooption and value was
                         greater than {SEM_VALUE_MAX}.

                      o  EMFILE-Too many semaphore descriptors or
                         file descriptors are currently in use by
                         this process.

                      o  ENAMETOOLONG-The length of the name string
                         exceeds {PATH_MAX}, or a pathname component
                         is longer than {NAME_MAX} while {_POSIX_NO_
                         TRUNC} is in effect.

                      o  ENFILE-Too many semaphores are currently
                         open in the system. ENOENT O_CREAT is
                         not set, and the named semaphore does not
                         exist.

                      o  ENOSPC-Insufficient space exists for the
                         creation of a new named semaphore.

                      o  EVMSERR-OpenVMS specific nontranslatable
                         error code.
 

2  semop
   Performs operations on semaphores in a semaphore set.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <sem.h>

     int semop  (int semid, struct sembuf *sops, size_t nsops);
 

3  Argument
 

semid

   Semaphore set identifier.
 

sops

   Pointer to a user-defined array of semaphore operation (sembuf)
   structures.
 

nsops

   Number of sembuf structures in the sops array.
 

3  Description
   The semop function performs operations on semaphores in the
   semaphore set specified by semid. These operations are supplied
   in a user-defined array of semaphore operation sembuf structures
   specified by sops. Each sembuf structure includes the following
   member variables:

   struct sembuf {            /* semaphore operation structure */
     unsigned short sem_num;  /* semaphore number */
              short sem_op;   /* semaphore operation */
              short sem_flg;  /* operation flags SEM_UNDO and IPC_NOWAIT */

   Each semaphore operation specified by the sem_op variable is
   performed on the corresponding semaphore specified by the semid
   function argument and the sem_num variable.

   The sem_op variable specifies one of three semaphore operations:

   1. If sem_op is a negative integer and the calling process has
      change permission, one of the following occurs:

      o  If semval (see <sem.h>) is greater than or equal to the
         absolute value of sem_op, the absolute value of sem_op
         is subtracted from semval. Also, if (sem_flg &SEM_UNDO)
         is non-zero, the absolute value of sem_op is added to the
         calling process' semadj value for the specified semaphore.

      o  If semval is less than the absolute value of sem_op
         and (sem_flg &IPC_NOWAIT) is nonzero, semop returns
         immediately.

      o  If semval is less than the absolute value of sem_op and
         (sem_flg &IPC_NOWAIT) is 0, semop increments the semncnt
         associated with the specified semaphore and suspends
         execution of the calling thread until one of the following
         conditions occurs:

         -  The value of semval becomes greater than or equal to the
            absolute value of sem_op. When this occurs, the value
            of semncnt associated with the specified semaphore is
            decremented, the absolute value of sem_op is subtracted
            from semval and, if (sem_flg &SEM_UNDO) is nonzero,
            the absolute value of sem_op is added to the calling
            process' semadj value for the specified semaphore.

         -  The semid for which the calling thread is awaiting
            action is removed from the system. When this occurs,
            errno is set equal to EIDRM and -1 is returned.

         -  The calling thread receives a signal that is to be
            intercepted. When this occurs, the value of semncnt
            associated with the specified semaphore is decremented,
            and the calling thread is resumes execution in the
            manner prescribed in sigaction.

   2. If sem_op is a positive integer and the calling process has
      change permission, the value of sem_op is added to semval
      and, if (sem_flg &SEM_UNDO) is nonzero, the value of sem_op
      is subtracted from the calling process' semadj value for the
      specified semaphore.

   3. If sem_op is 0 and the calling process has read permission,
      one of the following occurs:

      o  If semval is 0, semop returns immediately.

      o  If semval is nonzero and (sem_flg &IPC_NOWAIT) is nonzero,
         semop returns immediately.

      o  If semval is nonzero and (sem_flg &IPC_NOWAIT) is 0, semop
         increments the semzcnt associated with the specified
         semaphore and suspends execution of the calling thread
         until one of the following occurs:

         -  The value of semval becomes 0, at which time the value
            of semzcnt associated with the specified semaphore is
            decremented.

         -  The semid for which the calling thread is awaiting
            action is removed from the system. When this occurs,
            errno is set equal to EIDRM and -1 is returned.

         -  The calling thread receives a signal that is to be
            intercepted. When this occurs, the value of semzcnt
            associated with the specified semaphore is decremented,
            and the calling thread resumes execution in the manner
            prescribed in sigaction.

   On successful completion, the value of sempid for each semaphore
   specified in the array pointed to by sops is set equal to the
   process ID of the calling process.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  E2BIG - The value of nsops is greater than
                         the system-imposed maximum.

                      o  EACCES - Operation permission is denied to
                         the calling process.

                      o  EAGAIN - The operation would result in
                         suspension of the calling process but (sem_
                         flg &IPC_NOWAIT) is nonzero.

                      o  EFAULT - The arguments passed to the
                         function are not accessible.

                      o  EFBIG - The value of sem_num is less than
                         0 or greater than or equal to the number
                         of semaphores in the set associated with
                         semid.

                      o  EIDRM - The semaphore identifier semid is
                         removed from the system.

                      o  EINVAL - The value of semid is not a valid
                         semaphore identifier, or the number of
                         individual semaphores for which the calling
                         process requests a SEM_UNDO would exceed
                         the system-imposed limit.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  sem_post
   Unlocks a semaphore.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <semaphore.h>

     int sem_post  (sem_t *sem);
 

3  Argument
 

sem

   The semaphore to be unlocked.
 

3  Description
   The sem_post function unlocks the specified semaphore by
   performing the semaphore unlock operation on that semaphore. The
   appropriate function (sem_open for named semaphores or sem_init
   for unnamed semaphores) must be called for a semaphore before
   you can call the locking and unlocking functions, sem_wait, sem_
   trywait, and sem_post.

   If the semaphore value after a sem_post function is positive, no
   processes were blocked waiting for the semaphore to be unlocked;
   the semaphore value is incremented. If the semaphore value after
   a sem_post function is zero, one of the processes blocked waiting
   for the semaphore is allowed to return successfully from its call
   to sem_wait.

   If more than one process is blocked while waiting for the
   semaphore, only one process is unblocked and the state of
   the semaphore remains unchanged when the sem_post function
   returns. The process to be unblocked is selected according to
   the scheduling policies and priorities of all blocked processes.
   If the scheduling policy is SCHED_FIFO or SCHED_RR, the highest-
   priority waiting process is unblocked. If more than one process
   of that priority is blocked, then the process that has waited the
   longest is unblocked.

   The sem_post function can be called from a signal-catching
   function.
 

3  Return_Values

   0                  Successful completion. The sem_post function
                      performs a semaphore unlock operation,
                      unblocking a process.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EINVAL - The sem argument is not a valid
                         semaphore.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  sem_timedwait
   Performs a semaphore lock.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <semaphore.h>

     #include  <time.h>
                                                                    
     int sem_timedwait  (sem_t *sem, const struct timespec          
                        *abs_timeout);
 

3  Argument
 

sem

   The semaphore to be locked.
 

abs_timeout

   The absolute time after which the timeout expires.
 

3  Description
   The sem_timedwait function locks the semaphore referenced by
   sem as in the sem_wait function. But if the semaphore cannot be
   locked without waiting for another process or thread to unlock
   the semaphore by performing a sem_post function, this wait
   terminates when the specified timeout expires.

   The timeout expires when the absolute time specified by abs_
   timeout passes, as measured by the clock on which timeouts are
   based (that is, when the value of that clock equals or exceeds
   abs_timeout, or if the absolute time specified by abs_timeout has
   already been passed at the time of the call.

   The function will not fail with a timeout if the semaphore can be
   locked immediately. The validity of abs_timeout does not need to
   be checked if the semaphore can be locked immediately.
 

3  Return_Values

   0                  Successful completion. The function executes
                      the semaphore lock operation.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  ETIMEDOUT - The semaphore could not
                         be locked before the specified timeout
                         expired.

                      o  EINVAL - The sem argument does not refer to
                         a valid semaphore. Or the process or thread
                         would have blocked, and the abs_timeout
                         parameter specified a nanoseconds field
                         value less than zero or greater than or
                         equal to 1000 million.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  sem_trywait
   Conditionally performs a semaphore lock.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <semaphore.h>

     int sem_trywait  (sem_t *sem);
 

3  Argument
 

sem

   The semaphore to be locked.
 

3  Description
   The sem_trywait function locks a semaphore only if the semaphore
   is currently not locked. If the semaphore value is zero, the sem_
   trywait function returns without locking the semaphore.

   The sem_wait and sem_trywait functions help ensure that the
   resource associated with the semaphore cannot be accessed by
   other processes. The semaphore remains locked until the process
   unlocks it with a call to the sem_post function.

   Use the sem_wait function instead of the sem_trywait function if
   the process should wait for access to the semaphore.
 

3  Return_Values

   0                  Successful completion. The function executes
                      the semaphore lock operation.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EAGAIN - The semaphore was already locked
                         and cannot be locked by the sem_trywait
                         operation.

                      o  EINVAL - The sem argument does not refer to
                         a valid semaphore.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  sem_unlink
   Removes the specified named semaphore.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <semaphore.h>

     int sem_unlink  (const char *name);
 

3  Argument
 

name

   The name of the semaphore to remove.
 

3  Description
   The sem_unlink function removes a semaphore named by the name
   string. If the semaphore is referenced by other processes, sem_
   unlink does not change the state of the semaphore.

   If other processes have the semaphore open when sem_unlink is
   called, the semaphore is not destroyed until all references to
   the semaphore have been destroyed by calls to sem_close. The sem_
   unlink function returns immediately; it does not wait until all
   references have been destroyed.

   Calls to sem_open to recreate or reconnect to the semaphore refer
   to a new semaphore after sem_unlink is called.
 

3  Return_Values

   0                  Successful completion. The function executes
                      the semaphore unlink operation.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EACCESS - Permission is denied to unlink
                         the named semaphore.

                      o  ENAMETOOLONG - The length of the path
                         name exceeds PSEM_MAX_PATHNAME defined
                         in semaphore.h.

                      o  ENOENT - The named semaphore does not
                         exist.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  sem_wait
   Performs a semaphore lock.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <semaphore.h>

     int sem_wait  (sem_t *sem);
 

3  Argument
 

sem

   The semaphore to be locked.
 

3  Description
   The sem_wait function locks the semaphore referenced by sem by
   performing a semaphore lock operation on it. If the semaphore
   value is zero, the sem_wait function blocks until it either locks
   the semaphore or is interrupted by a signal.

   The sem_wait and sem_trywait functions help ensure that the
   resource associated with the semaphore cannot be accessed by
   other processes. The semaphore remains locked until the process
   unlocks it with a call to the sem_post function.

   Use the sem_wait function instead of the sem_trywait function if
   the process should wait for access to the semaphore.
 

3  Return_Values

   0                  Successful completion. The function executes
                      the semaphore lock operation.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EINTR - A signal interrupted this function.

                      o  EVMSERR - OpenVMS specific nontranslatable
                         error code.
 

2  [w]setattr
   Activate the video display attribute attr within the window. The
   setattr function acts on the stdscr window.

   Format

     #include  <curses.h>

     int setattr  (int attr);

     int wsetattr  (WINDOW *win, int attr);
 

3  Arguments
 

win

   A pointer to the window.
 

attr

   One of a set of video display attributes, which are blinking,
   boldface, reverse video, and underlining, and are represented by
   the defined constants _BLINK, _BOLD, _REVERSE, and _UNDERLINE,
   respectively. You can set multiple attributes by separating them
   with a bitwise OR operator (|) as follows:

   setattr(_BLINK | _UNDERLINE);
 

3  Description
   The setattr and wsetattr functions are specific to Compaq C for
   OpenVMS Systems and are not portable.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  setbuf
   Associates a new buffer with an input or output file and
   potentially modifies the buffering behavior.

   Format

     #include  <stdio.h>

     void setbuf  (FILE *file_ptr, char *buffer);
 

3  Arguments
 

file_ptr

   A file pointer.
 

buffer

   A pointer to a character array or a NULL pointer.
 

3  Description
   You can use the setbuf function after the specified file is
   opened but before any I/O operations are performed.

   If buffer is a NULL pointer, then the call is equivalent to a
   call to setvbuf with the same file_ptr, a NULL buffer pointer, a
   buffering type of _IONBF (no buffering), and a buffer size of 0.

   If buffer is not a NULL pointer, then the call is equivalent to a
   call to setvbuf with the same file_ptr, the same buffer pointer,
   a buffering type of _IOFBF, and a buffer size given by the value
   BUFSIZ (defined in <stdio.h>). Therefore, use BUFSIZ to allocate
   the buffer argument used in the call to setbuf. For example:

   #include <stdio.h>
      .
      .
      .
   char my_buf[BUFSIZ];
      .
      .
      .
   setbuf(stdout, my_buf);
      .
      .
      .

   User programs must not depend on the contents of buffer once I/O
   has been performed on the stream. The Compaq C RTL might or might
   not use buffer for any given I/O operation.

   The setbuf function originally allowed programmers to substitute
   larger buffers in place of the system default buffers in obsolete
   versions of UNIX. The large default buffer sizes in modern
   implementations of C make the use of this function unnecessary
   most of the time. The setbuf function is retained in the ANSI C
   standard for compatibility with old programs. New programs should
   use setvbuf instead, because it allows the programmer to bind the
   buffer size at run time instead of compile time, and it returns a
   result value that can be tested.
 

2  setenv
   Inserts or resets the environment variable specified by name in
   the current environment list.

   Format

     #include  <stdlib.h>

     int setenv  (const char *name, const char *value, int          
                 overwrite);
 

3  Arguments
 

name

   A variable name in the environment variable list.
 

value

   The value for the environment variable.
 

overwrite

   A value of 0 or 1 indicating whether to reset the environment
   variable, if it exists.
 

3  Description
   The setenv function inserts or resets the environment variable
   name in the current environment list. If the variable name does
   not exist in the list, it is inserted with the value argument. If
   the variable does exist, the overwrite argument is tested. When
   the overwrite argument value is:

   o  0 then the variable is not reset.

   o  1 then the variable is reset to value.

                                  NOTE

      Do not use the setenv, getenv, and putenv functions to
      manipulate symbols and logicals. Instead, use the OpenVMS
      library calls lib$set_logical, lib$get_logical, lib$set_
      symbol, and lib$get_symbol. The *env functions deliberately
      provide UNIX behavior, and are not a substitute for these
      OpenVMS runtime library calls.

      OpenVMS DCL symbols, not logical names, are the closest
      analog to environment variables on UNIX systems. While
      getenv is a mechanism to retrieve either a logical name
      or a symbol, it maintains an internal cache of values for
      use with setenv and subsequent getenv calls. The setenv
      function does not write or create DCL symbols or OpenVMS
      logical names.

      This is consistent with UNIX behavior. On UNIX systems,
      setenv does not change or create any symbols that will be
      visible in the shell after the program exits.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error. errno is set to ENOMEM-
                      Not enough memory available to expand the
                      environment list.
 

2  seteuid
   Sets the process's effective user ID.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     int seteuid  (uid_t euid);
 

3  Argument
 

euid

   The value to which you want the effective user ID set.
 

3  Description
   If the process has the IMPERSONATE privilege, the seteuid
   function sets the process's effective user ID.

   An unprivileged process can set the effective user ID only if the
   euid argument is equal to either the real, effective, or saved
   user ID of the process.

   This function requires that long (32-bit) UID/GID support be
   enabled. See 32-Bit UID and GID Macro (Integrity servers, Alpha)
   for more information.

   See also getuid to know how UIC is represented.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EINVAL - The value of the euid argument is
                         invalid and not supported.

                      o  EPERM - The process does not have the
                         IMPERSONATE privilege, and euid does not
                         match the real user ID or the saved set-
                         user-ID.
 

2  setgid
   With POSIX IDs disabled, setgid is implemented for program
   portability and serves no function. It returns 0 (to indicate
   success).

   With POSIX IDs enabled, setgid sets the group IDs.

   Format

     #include  <types.h>

     #include  <unistd.h>

     int setgid  (__gid_t gid); (_DECC_V4_SOURCE)

     int setgid  (gid_t gid); (not _DECC_V4_SOURCE)
 

3  Argument
 

gid

   The value to which you want the group IDs set.
 

3  Description
   The setgid function can be used with POSIX style identifiers
   enabled or disabled.

   POSIX style IDs are supported on OpenVMS Version 7.3-2 and
   higher.

   With POSIX IDs disabled, the setgid function is implemented for
   program portability and serves no function. It returns 0 (to
   indicate success).

   With POSIX style IDs enabled:

   o  If the process has the IMPERSONATE privilege, the setgid
      function sets the real group ID, effective group ID, and the
      saved set-group-ID to gid.

   o  If the process does not have appropriate privileges but gid is
      equal to the real group ID or to the saved set-group-ID, then
      the setgid function sets the effective group ID to gid. The
      real group ID and saved set-group-ID remain unchanged.

   o  Any supplementary group IDs of the calling process remain
      unchanged.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EINVAL - The value of the gid argument
                         is invalid and not supported by the
                         implementation.

                      o  EPERM - The process does not have
                         appropriate privileges and gid does not
                         match the real group ID or the saved set-
                         group-ID.
 

2  setgrent
   Rewinds the group database.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <grp.h>

     void setgrent  (void);
 

3  Description
   The setgrent function effectively rewinds the group database to
   allow repeated searches.

   This function is always successful. No value is returned, and
   errno is not set.
 

2  setitimer
   Sets the value of interval timers.

   Format

     #include  <time.h>

     int setitimer  (int which, struct itimerval *value, struct     
                    itimerval *ovalue);
 

3  Arguments
 

which

   The type of interval timer. The Compaq C RTL only supports
   ITIMER_REAL.
 

value

   A pointer to an itimerval structure whose members specify a timer
   interval and the time left to the end of the interval.
 

ovalue

   A pointer to an itimerval structure whose members specify a
   current timer interval and the time left to the end of the
   interval.
 

3  Description
   The setitimer function sets the timer specified by which to the
   value specified by value, returning the previous value of the
   timer if ovalue is nonzero.

   A timer value is defined by the itimerval structure:

          struct itimerval {
                  struct  timeval it_interval;
                  struct  timeval it_value;
          };

   The value of the itimerval structure members are: as follows

   itimerval Member
   Value              Meaning

   it_interval = 0    Disables a timer after its next expiration
                      (assumes it_value is nonzero).
   it_interval =      Specifies a value used in reloading it_value
   nonzero            when the timer expires.
   it_value = 0       Disables a timer.
   it_value =         Indicates the time to the next timer
   nonzero            expiration.

   Time values smaller than the resolution of the system clock are
   rounded up to this resolution.

   The getitimer function provides one interval timer, defined in
   the <time.h> header file as ITIMER_REAL. This timer decrements in
   real time. When the timer expires, it delivers a SIGALARM signal.

                                  NOTE

      The interaction between setitimer and any of alarm, sleep,
      or usleep is unspecified.
 

3  Return_Values

   0                  Indicates success.
   -1                 An error occurred; errno is set to indicate
                      the error.
 

2  setjmp
   Provides a way to transfer control from a nested series of
   function invocations back to a predefined point without returning
   normally. It does not use a series of return statements. The
   setjmp function saves the context of the calling function in an
   environment buffer.

   Format

     #include  <setjmp.h>

     int setjmp  (jmp_buf env);
 

3  Argument
 

env

   The environment buffer, which must be an array of integers long
   enough to hold the register context of the calling function.
   The type jmp_buf is defined in the <setjmp.h> header file. The
   contents of the general-purpose registers, including the program
   counter (PC), are stored in the buffer.
 

3  Description
   When setjmp is first called, it returns the value 0. If longjmp
   is then called, naming the same environment as the call to
   setjmp, control is returned to the setjmp call as if it had
   returned normally a second time. The return value of setjmp in
   this second return is the value supplied by you in the longjmp
   call. To preserve the true value of setjmp, the function calling
   setjmp must not be called again until the associated longjmp is
   called.

   The setjmp function preserves the hardware general-purpose
   registers, and the longjmp function restores them. After a
   longjmp, all variables have their values as of the time of the
   longjmp except for local automatic variables not marked volatile.
   These variables have indeterminate values.

   The setjmp and longjmp functions rely on the OpenVMS
   condition-handling facility to effect a nonlocal goto with
   a signal handler. The longjmp function is implemented by
   generating a Compaq C RTL specified signal that allows the
   OpenVMS condition-handling facility to unwind back to the desired
   destination.

   The Compaq C RTL must be in control of signal handling for any
   Compaq C image. For Compaq C to be in control of signal handling,
   you must establish all exception handlers through a call to the
   VAXC$ESTABLISH function.

                                  NOTE

      The C RTL provides nonstandard decc$setjmp and decc$fast_
      longjmp functions for Alpha and Integrity server systems. To
      use these nonstandard functions instead of the standard
      ones, a program must be compiled with __FAST_SETJMP or
      __UNIX_SETJMP macros defined.

      Unlike the standard longjmp function, the decc$fast_longjmp
      function does not convert its second argument from 0 to 1.
      After a call to decc$fast_longjmp, a corresponding setjmp
      function returns with the exact value of the second argument
      specified in the decc$fast_longjmp call.
 

3  Restrictions
   You cannot invoke the longjmp function from an OpenVMS condition
   handler. However, you may invoke longjmp from a signal handler
   that has been established for any signal supported by the
   Compaq C RTL, subject to the following nesting restrictions:

   o  The longjmp function will not work if you invoke it from
      nested signal handlers. The result of the longjmp function,
      when invoked from a signal handler that has been entered as a
      result of an exception generated in another signal handler, is
      undefined.

   o  Do not invoke the setjmp function from a signal handler unless
      the associated longjmp is to be issued before the handling of
      that signal is completed.

   o  Do not invoke the longjmp function from within an exit handler
      (established with atexit or SYS$DCLEXH). Exit handlers are
      invoked after image tear-down, so the destination address of
      the longjmp no longer exists.

   o  Invoking longjmp from within a signal handler to return to
      the main thread of execution might leave your program in
      an inconsistent state. Possible side effects include the
      inability to perform I/O or to receive any more UNIX signals.
      Use siglongjmp instead.
 

3  Return_Values

   See the
   Description
   section.
 

2  setkey
   Sets an encoding key for use by the encrypt function.

   Format

     #include  <unistd.h>

     #include  <stdlib.h>

     void setkey  (const char *key;)
 

3  Argument
 

key

   A character array of length 64 containing 0s and 1s.
 

3  Description
   The argument of setkey is a character array of length 64
   containing only the characters with numerical value 0 and 1.
   If this string is divided into groups of 8, the low-order bit in
   each group is ignored, leading to a 56-bit key which is set into
   the machine.

   No value is returned.

   See also crypt and encrypt.
 

2  setlocale
   Selects the appropriate portion of the program's locale as
   specified by the category and locale arguments. You can use this
   function to change or query one category or the program's entire
   current locale.

   Format

     #include  <locale.h>

     char *setlocale  (int category, const char *locale);
 

3  Arguments
 

category

   The name of the category. Specify LC_ALL to change or query the
   entire locale. Other valid category names are:

   o  LC_COLLATE

   o  LC_CTYPE

   o  LC_MESSAGES

   o  LC_MONETARY

   o  LC_NUMERIC

   o  LC_TIME
 

locale

   Pointer to a string that specifies the locale.
 

3  Description
   The setlocale function sets or queries the appropriate portion
   of the program's locale as specified by the category and locale
   arguments. Specifying LC_ALL for the category argument names the
   entire locale; specifying the other values name only a portion of
   the program's locale.

   The locale argument points to a character string that identifies
   the locale to be used. This argument can be one of the following:

   o  Name of the public locale

      Specifies the public locale in the following format:

      language_country.codeset[@modifier]

      The function searches for the public locale binary file in
      the location defined by the logical name SYS$I18N_LOCALE. The
      file type defaults to .LOCALE. The period (.)  and at-sign (@)
      characters in the name are replaced by an underscore (_).

      For example, if the specified name is
      "zh_CN.dechanzi@radical", the function searches for the
      SYS$I18N_LOCALE:ZH_CN_DECHANZI_RADICAL.LOCALE binary locale
      file.

   o  A file specification

      Specifies the binary locale file. It can be any valid file
      specification. If either the device or directory is omitted,
      the function first applies the current caller's device and
      directory as defaults for any missing component. If the file
      is not found, the function applies the device and directory
      defined by the SYS$I18N_LOCALE logical name as defaults. The
      file type defaults to .LOCALE.

      No wildcards are allowed. The binary locale file cannot reside
      on a remote node.

   o  "C"

      Specifies the C locale. If a program does not call setlocale,
      the C locale is the default.

   o  "POSIX"

      This is the same as the C locale.

   o  ""

      Specifies that the locale is initialized from the setting
      of the international environment logical names. The function
      checks the following logical names in the order shown until it
      finds a logical that is defined:

      1. LC_ALL

      2. Logical names corresponding to the category. For example,
         if LC_NUMERIC is specified as the category, then the first
         logical name that setlocale checks is LC_NUMERIC.

      3. LANG

      4. SYS$LC_ALL

      5. The system default for the category, which is defined by
         the SYS$LC_* logical names. For example, the default for
         the LC_NUMERIC category is defined by the SYS$LC_NUMERIC
         logical name.

      6. SYS$LANG

         If none of the logical names is defined, the C locale is
         used as the default. The SYS$LC_* logical names are set up
         at the system startup time.

      Like the locale argument, the equivalence name of the
      international environment logical name can be either the name
      of the public locale or the file specification. The setlocale
      function treats this equivalence name as if it were specified
      as the locale argument.

   o  NULL

      Causes setlocale to query the current locale. The function
      returns a pointer to a string describing the portion of the
      program's locale associated with category. Specifying the LC_
      ALL category returns the string describing the entire locale.
      The locale is not changed.

   o  The string returned from the previous call to setlocale

      Causes the function to restore the portion of the program's
      locale associated with category. If the string contains the
      description of the entire locale, the part of the string
      corresponding to category is used. If the string describes the
      portion of the program's locale for a single category, this
      locale is used. For example, this means that you can use the
      string returned from the call setlocale with the LC_COLLATE
      category to set the same locale for the LC_MESSAGES category.

      If the specified locale is available, then setlocale returns
      a pointer to the string that describes the portion of the
      program's locale associated with category. For the LC_ALL
      category, the returned string describes the entire program's
      locale. If an error occurs, a NULL pointer is returned and the
      program's locale is not changed.

      Subsequent calls to setlocale overwrite the returned string.
      If that part of the locale needs to be restored, the program
      should save the string. The calling program should make no
      assumptions about the format or length of the returned string.
 

3  Return_Values

   x                  Pointer to a string describing the locale.
   NULL               Indicates an error occurred; errno is set.
 

3  Example

       #include <errno.h>
       #include <stdio.h>
       #include <locale.h>

       /* This program calls setlocale() three times. The second call  */
       /* is for a nonexistent locale. The third call is for an        */
       /* existing file that is not a locale file.                     */

       main()
       {
           char *ret_str;

           errno = 0;
           printf("setlocale (LC_ALL, \"POSIX\")");
           ret_str = (char *) setlocale(LC_ALL, "POSIX");

           if (ret_str == NULL)
               perror("setlocale error");
           else
               printf(" call was successful\n");

           errno = 0;
           printf("\n\nsetlocale (LC_ALL, \"junk.junk_codeset\")");
           ret_str = (char *) setlocale(LC_ALL, "junk.junk_codeset");

           if (ret_str == NULL)
               perror(" returned error");
           else
               printf(" call was successful\n");

           errno = 0;
           printf("\n\nsetlocale (LC_
ALL, \"sys$login:login.com\")");
           ret_str = (char *) setlocale(LC_
ALL, "sys$login:login.com");

           if (ret_str == NULL)
               perror(" returned error");
           else
               printf(" call was successful\n");
       }

     Running the example program produces the following result:

       setlocale (LC_ALL, "POSIX") call was successful

       setlocale (LC_ALL, "junk.junk_codeset")
       returned error: no such file or directory

       setlocale (LC_ALL, "sys$login:login.com")
       returned error: nontranslatable vms error code: 0x35C07C
       %c-f-localebad, not a locale file
 

2  setpgid
   Sets the process group ID for job control.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     int setpgid  (pid_t pid, pid_t pgid);
 

3  Arguments
 

pid

   The process ID for which the process group ID is to be set.
 

pgid

   The value to which the process group ID is set.
 

3  Description
   The setpgid function is used either to join an existing process
   group or create a new process group within the session of the
   calling process. The process group ID of a session leader will
   not change.

   Upon successful completion, the process group ID of the process
   with a process ID of pid is set to pgid. As a special case, if
   pid is 0, the process ID of the calling process is used. Also, if
   pgid is 0, the process group ID of the indicated process is used.

   This function requires that long (32-bit) UID/GID support be
   enabled. See 32-Bit UID and GID Macro (Integrity servers, Alpha)
   for more information.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EACCES - The value of the pid argument
                         matches the process ID of a child process
                         of the calling process and the child
                         process has successfully executed one of
                         the exec functions.

                      o  EINVAL - The value of the pgid argument is
                         less than 0, or is not a value supported by
                         the implementation.

                      o  EPERM - The process indicated by the pid
                         argument is a session leader. The value
                         of the pid argument matches the process ID
                         of a child process of the calling process,
                         and the child process is not in the same
                         session as the calling process. The value
                         of the pgid argument is valid but does
                         not match the process ID of the process
                         indicated by the pid argument, and there
                         is no process with a process group ID that
                         matches the value of the pgid argument in
                         the same session as the calling process.

                      o  ESRCH - The value of the pid argument does
                         not match the process ID of the calling
                         process or of a child process of the
                         calling process.
 

2  setpgrp
   Sets the process group ID.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     pid_t setpgrp  (void);
 

3  Description
   If the calling process is not already a session leader, setpgrp
   sets the process group ID of the calling process to the process
   ID of the calling process. If setpgrp creates a new session, then
   the new session has no controlling terminal.

   The setpgrp function has no effect when the calling process is a
   session leader.

   This function requires that long (32-bit) UID/GID support be
   enabled. See 32-Bit UID and GID Macro (Integrity servers, Alpha)
   for more information.
 

3  Return_Value

   x                  The process group ID of the calling process.
 

2  setpwent
   Rewinds the user database.

   Format

     #include  <pwd.h>

     void setpwent  (void);
 

3  Description
   The setpwent function effectively rewinds the user database to
   allow repeated searches.

   No value is returned, but errno is set to EIO if an I/O error
   occurred.

   See also getpwent.
 

2  setregid
   Sets the real and effective group IDs.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     int setregid  (gid_t rgid, gid_t egid);
 

3  Arguments
 

rgid

   The value to which you want the real group ID set.
 

egid

   The value to which you want the effective group ID set.
 

3  Description
   The setregid function is used to set the real and effective group
   IDs of the calling process. If rgid is -1, the real group ID
   is not changed; if egid is -1, the effective group ID is not
   changed. The real and effective group IDs can be set to different
   values in the same call.

   Only a process with the IMPERSONATE privilege can set the real
   group ID and the effective group ID to any valid value.

   A nonprivileged process can set either the real group ID to the
   saved set-group-ID from an exec function, or the effective group
   ID to the saved set-group-ID or the real group ID.

   Any supplementary group IDs of the calling process remain
   unchanged.

   If a set-group-ID process sets its effective group ID to its real
   group ID, it can still set its effective group ID back to the
   saved set-group-ID.

   This function requires that long (32-bit) UID/GID support be
   enabled. See 32-Bit UID and GID Macro (Integrity servers, Alpha)
   for more information.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. Neither of the group IDs
                      is changed, and errno is set to one of the
                      following values:

                      o  EINVAL - The value of the rgid or egid
                         argument is invalid or out-of-range.

                      o  EPERM - The process does not have the
                         IMPERSONATE privilege, and a change
                         other than changing the real group ID to
                         the saved set-group-ID, or changing the
                         effective group ID to the real group ID or
                         the saved group ID, was requested.
 

2  setreuid
   Sets the user IDs.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     int setreuid  (uid_t ruid, uid_t euid);
 

3  Arguments
 

ruid

   The value to which you want the real user ID set.
 

euid

   The value to which you want the effective user ID set.
 

3  Description
   The setreuid function sets the real and effective user IDs of
   the current process to the values specified by the ruid and euid
   arguments. If ruid or euid is -1, the corresponding effective or
   real user ID of the current process is left unchanged.

   A process with the IMPERSONATE privilege can set either ID to any
   value. An unprivileged process can set the effective user ID only
   if the euid argument is equal to either the real, effective, or
   saved user ID of the process.

   It is unspecified whether a process without the IMPERSONATE
   privilege is permitted to change the real user ID to match the
   current real, effective, or saved user ID of the process.

   This function requires that long (32-bit) UID/GID support be
   enabled. See 32-Bit UID and GID Macro (Integrity servers, Alpha)
   for more information.

   See also getuid to know how UIC is represented.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EINVAL - The value of the ruid or euid
                         argument is invalid or out of range.

                      o  EPERM - The current process does not have
                         the IMPERSONATE privilege, and either an
                         attempt was made to change the effective
                         user ID to a value other than the real user
                         ID or the saved set-user-ID, or an attempt
                         was made to change the real user ID to a
                         value not permitted by the implementation.
 

2  setsid
   Creates a session and sets the process group ID.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     pid_t setsid  (void);
 

3  Description
   The setsid function creates a new session if the calling process
   is not a process group leader. Upon return, the calling process
   is the session leader of this new session and the process
   group leader of a new process group, and it has no controlling
   terminal. The process group ID of the calling process is set
   equal to the process ID of the calling process. The calling
   process is the only process in the new process group and the
   only process in the new session.

   This function requires that long (32-bit) UID/GID support be
   enabled. See 32-Bit UID and GID Macro (Integrity servers, Alpha)
   for more information.
 

3  Return_Values

   x                  The process group ID of the calling process.
   (pid_t)-1          Indicates an error. The function sets errno to
                      the following value:

                      o  EPERM - The calling process is already a
                         process group leader, or the process group
                         ID of a process other than the calling
                         process matches the process ID of the
                         calling process.
 

2  setstate
   Restarts and changes random-number generators.

   Format

     char *setstate  (char *state;)
 

3  Argument
 

state

   Points to the array of state information.
 

3  Description
   The setstate function handles restarting and changing random-
   number generators.

   Once you initialize a state, the setstate function allows rapid
   switching between state arrays. The array defined by state is
   used for further random-number generation until the initstate
   function is called or the setstate function is called again. The
   setstate function returns a pointer to the previous state array.

   After initialization, you can restart a state array at a
   different point in one of two ways:

   o  Use the initstate function, with the desired seed, state
      array, and size of the array.

   o  Use the setstate function, with the desired state, followed by
      the srandom function with the desired seed. The advantage of
      using both functions is that you do not have to save the state
      array size once you initialize it.

   See also initstate, srandom, and random.
 

3  Return_Values

   x                  A pointer to the previous state array
                      information.
   0                  Indicates an error. The state information is
                      damaged, and errno is set to the following
                      value:

                      o  EINVAL-The state argument is invalid.
 

2  setuid
   With POSIX IDs disabled, implemented for program portability and
   serves no function. It returns 0 (to indicate success).

   With POSIX IDs enabled, sets the user IDs.

   Format

     #include  <types.h>

     #include  <unistd.h>

     int setuid  (__uid_t uid); (_DECC_V4_SOURCE)

     uid_t setuid  (uid_t uid); (not _DECC_V4_SOURCE)
 

3  Argument
 

uid

   The value to which you want the user IDs set.
 

3  Description
   The setuid function can be used with POSIX style identifiers
   enabled or disabled.

   POSIX style IDs are supported on OpenVMS Version 7.3-2 and
   higher.

   With POSIX IDs disabled (the default), the setuid function is
   implemented for program portability and serves no function. It
   returns 0 (to indicate success).

   With POSIX style IDs enabled:

   o  If the process has the IMPERSONATE privilege, the setuid
      function sets the real user ID, effective user ID, and the
      saved set-user-ID to uid.

   o  If the process does not have appropriate privileges but uid
      is equal to the real user ID or to the saved set-user-ID, then
      the setuid function sets the effective user ID to uid. The
      real user ID and saved set-user-ID remain unchanged.

   See also getuid to know how UIC is represented.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EINVAL - The value of the uid argument
                         is invalid and not supported by the
                         implementation.

                      o  EPERM - The process does not have
                         appropriate privileges and uid does not
                         match the real user ID or the saved set-
                         user-ID.
 

2  setvbuf
   Associates a buffer with an input or output file and potentially
   modifies the buffering behavior.

   Format

     #include  <stdio.h>

     int setvbuf  (FILE *file_ptr, char *buffer, int type, size_t size);
 

3  Arguments
 

file_ptr

   A pointer to a file.
 

buffer

   A pointer to a character array, or a NULL pointer.
 

type

   The buffering type. Use one of the following values defined in
   <stdio.h>: _IOFBF or _IOLBF.
 

size

   The number of bytes to be used in buffer by the Compaq C RTL for
   buffering this file. The buffer size must be a minimum of 8192
   bytes and a maximum of 32767 bytes.
 

3  Description
   You can use the setvbuf function after the file is opened but
   before any I/O operations are performed.

   The C RTL provides the following types of ANSI-conforming file
   buffering:

   In line-buffered I/O, characters are buffered in an area of
   memory until a new-line character is seen, at which point the
   appropriate RMS routine is called to transmit the entire buffer.
   Line buffering is more efficient than unbuffered I/O since it
   reduces the system overhead, but it delays the availability of
   the data to the user or disk on output.

   In fully buffered I/O, characters are buffered in an area of
   memory until the buffer is full, regardless of the presence of
   break characters. Full buffering is more efficient than line
   buffering or unbuffered I/O, but it delays the availability of
   output data even longer than line buffering.

   Use the values _IOLBF and _IOFBF defined in <stdio.h> for the
   type argument to specify line-buffered and fully buffered I/O,
   respectively.

   If file_ptr specifies a terminal device, the Compaq C RTL uses
   line-buffered I/O; otherwise, it uses fully buffered I/O.

   Please note that the previously documented value _IONBF is not
   supported.

   The Compaq C RTL automatically allocates a buffer to use for each
   I/O stream, so there are several buffer allocation possibilities:

   o  If buffer is not a NULL pointer and size is not smaller than
      the automatically allocated buffer, then setvbuf uses buffer
      as the file buffer.

   o  If buffer is a NULL pointer or size is smaller than the
      automatically allocated buffer, the automatically allocated
      buffer is used as the buffer area.

   o  If buffer is a NULL pointer and size is larger than the
      automatically allocated buffer, then setvbuf allocates a new
      buffer equal to the specified size and uses that as the file
      buffer.

   User programs must not depend on the contents of buffer once I/O
   has been performed on the stream. The Compaq C RTL might or might
   not use buffer for any given I/O operation.

   Generally, it is unnecessary to use setvbuf or setbuf to control
   the buffer size used by the Compaq C RTL. The automatically
   allocated buffer sizes are chosen for efficiency based on the
   kind of I/O operations performed and the device characteristics
   (such as terminal, disk, or socket).

   The setvbuf and setbuf functions are useful to introduce
   buffering for improved performance when writing a large amount of
   text to the stdout stream. This stream is unbuffered by default
   when bound to a terminal device (the normal case), and therefore
   incurs a large number of OpenVMS buffered I/O operations unless
   Compaq C RTL buffering is introduced by a call to setvbuf or
   setbuf.

   The setvbuf function is used only to control the buffering used
   by the Compaq C RTL, not the buffering used by the underlying RMS
   I/O operations. You can modify RMS default buffering behavior by
   specifying various values for the ctx, fop, rat, gbc, mbc, mbf,
   rfm, and rop RMS keywords when the file is opened by the creat,
   freopen or open functions.
 

3  Return_Values

   0                  Indicates success.
   nonzero value      Indicates that an invalid input value was
                      specified for type or file_ptr, or because
                      file_ptr is being used by another thread.
 

2  shm_open
   Opens a shared memory object.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <sys/mman.h>

     int shm_open  (const char *name, int oflag, mode_t mode);
 

3  Argument
 

name

   Pointer to a string naming a shared memory object.
 

oflag

   Specifies options that define file status and file access modes.
   This argument is constructed from the bitwise inclusive OR of
   zero or more of the options defined in the <fcntl.h> header file.
 

mode

   The shared memory object's permission bits. This argument is used
   only when the shared memory object is being created.
 

3  Description
   The shm_open function establishes a connection between a shared
   memory object and a file descriptor. It creates an open file
   description that refers to the shared memory object and a file
   descriptor that refers to that open file description. The file
   descriptor is used by other functions to refer to that shared
   memory object. The name argument points to a string naming a
   shared memory object. The name can be a pathname, in which case
   other processes referring to the same pathname refer to the same
   shared memory object.

   When a shared memory object is created, its state and all data
   associated with it persist until the shared memory is unlinked.

   The shm_open function returns a file descriptor for the shared
   memory object that is the lowest numbered file descriptor not
   currently open for that process.

   The file status flags and file access modes of the open file
   description are set according to the value of oflag, and can have
   zero or more of the following values:

      O_RDONLY - Open for read access only.

      O_RDWR - Open for read or write access.


      O_CREAT - Create the shared memory if the memory object does
      not exist already. The user ID and group ID of the shared
      memory object are identical to those of the calling process.
      The shared memory object's permission bits are set to the
      value of mode, except those set in the file mode creation mask
      of the process.


      O_EXCL - Prevent the opening of a shared memory object if O_
      CREAT is set and the shared memory object already exists. Use
      this option only in combination with O_CREAT.


      O_TRUNC - Truncate the shared memory object to zero length if
      it is successfully opened for read or write access (O_RDWR).

   The initial contents of the shared memory object are binary
   zeros.
 

3  Return_Values

   n                  Upon success, a nonnegative integer
                      representing the lowest numbered unused file
                      descriptor. The file descriptor points to the
                      shared memory object.
   -1                 Indicates failure. errno is set to indicate
                      the error:

                      o  EACCES - Permission to create the shared
                         memory object is denied, or the shared
                         memory object exists and the permissions
                         specified by oflag are denied, or O_TRUNC
                         is specified and write permission is
                         denied.

                      o  EEXIST - O_CREAT and O_EXCL are set, but
                         the named shared memory object already
                         exists.

                      o  EINTR - A signal has interrupted the shm_
                         open operation.

                      o  EINVAL - The shm_open operation is not
                         supported for the given name.

                      o  EMFILE - Too many file descriptors are
                         currently in use by this process.

                      o  ENAMETOOLONG - The length of the name
                         argument exceeds PATH_MAX or a pathname
                         component is longer than NAME_MAX.

                      o  ENFILE - Too many shared memory objects are
                         currently open in the system.

                      o  ENOENT - O_CREAT is not set and the named
                         shared memory object does not exist.

                      o  ENOSPC - Memory space for creation of the
                         new shared memory object is insufficient.
 

2  shm_unlink
   Removes a shared memory object.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <sys/mman.h>

     int shm_unlink  (const char *name);
 

3  Argument
 

name

   Pointer to a string naming the shared memory object to remove.
 

3  Description
   The shm_unlink function removes the name of the shared memory
   object named by the string pointed to by name.

   If one or more references to the shared memory object exist
   when the object is unlinked, the name is removed before shm_
   unlink returns, but the removal of the memory object contents is
   postponed until all open and map references to the shared memory
   object have been removed.

   Even if the object continues to exist after the last shm_unlink,
   reuse of the name subsequently causes shm_unlink to behave as
   if no shared memory object with this name exists (that is, shm_
   open will fail if O_CREAT is not set, or will create a new shared
   memory object if O_CREAT is set).
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates failure, the named shared memory
                      object is not changed by the function call,
                      and errno is set to indicate the error:

                      o  EACCES - Permission is denied to unlink the
                         named shared memory object.

                      o  ENAMETOOLONG - The length of the name
                         argument exceeds PATH_MAX or a pathname
                         component is longer than NAME_MAX.

                      o  ENOENT - The named shared memory object
                         does not exist.
 

2  sigaction
   Specifies the action to take upon delivery of a signal.

   Format

     #include  <signal.h>

     int sigaction  (int sig, const struct sigaction *action, struct
                    sigaction *o_action);
 

3  Arguments
 

sig

   The signal for which the action is to be taken.
 

action

   A pointer to a sigaction structure that describes the action to
   take when you receive the signal specified by the sig argument.
 

o_action

   A pointer to a sigaction structure. When the sigaction function
   returns from a call, the action previously attached to the
   specified signal is stored in this structure.
 

3  Description
   When a process requests the sigaction function, the process
   can both examine and specify what action to perform when the
   specified signal is delivered. The arguments determine the
   behavior of the sigaction function as follows:

   o  Specifying the sig argument identifies the affected signal.
      Use any one of the signal values defined in the <signal.h>
      header file, except SIGKILL.

      If sig is SIGCHLD and the SA_NOCLDSTOP flag is not set in
      sa_flags, then a SIGCHLD signal is generated for the calling
      process whenever any of its child processes stop. If sig is
      SIGCHLD and the SA_NOCLDSTOP flag is set in sa_flags, then
      SIGCHLD signal is not generated in this way.

   o  Specifying the action argument, if not null, points to a
      sigaction structure that defines what action to perform when
      the signal is received. If the action argument is null, signal
      handling remains unchanged, so you can use the call to inquire
      about the current handling of the signal.

   o  Specifying the o_action argument, if not null, points to
      a sigaction structure that contains the action previously
      attached to the specified signal.

   The sigaction structure consists of the following members:

     void        (*sa_handler)(int);
     sigset_t    sa_mask;
     int         sa_flags;

   The sigaction structure members are defined as follows:

   sa_        This member can contain the following values:
   handler
              o  SIG_DFL - Specifies the default action taken when
                 the signal is delivered.

              o  SIG_IGN - Specifies that the signal has no effect on
                 the receiving process.

              o  Function pointer - Requests to catch the signal. The
                 signal causes the function call.

   sa_mask    This member can request that individual signals, in
              addition to those in the process signal mask, are
              blocked from delivery while the signal handler function
              specified by the sa_handler member is executing.
   sa_flags   This member can set the flags to enable further control
              over the actions taken when a signal is delivered.

   The sa_flags member of the sigaction structure has the following
   values:

   SA_ONSTACK     Setting this bit causes the system to run the
                  signal catching function on the signal stack
                  specified by the sigstack function. If this bit
                  is not set, the function runs on the stack of the
                  process where the signal is delivered.
   SA_RESETHAND   Setting this bit resets the signal to SIG_DFL. Be
                  aware that you cannot automatically reset SIGILL
                  and SIGTRAP.
   SA_NODEFER     Setting this bit does not automatically block the
                  signal as it is intercepted.
   SA_NOCLDSTOP   If this bit is set and the sig argument is equal
                  to SIGCHLD and a child process of the calling
                  process stops, then a SIGCHLD signal is sent to
                  the calling process only if SA_NOCLDSTOP is not
                  set for SIGCHLD.

   When a signal is intercepted by a signal-catching function
   installed by sigaction, a new signal mask is calculated and
   installed for the duration of the signal-catching function (or
   until a call to either sigprocmask or sigsuspend is made. This
   mask is formed by taking the union of the current signal mask and
   the value of the sa_mask for the signal being delivered unless
   SA_NODEFER or SA_RESETHAND is set, and then including the signal
   being delivered. If and when the user's signal handler returns
   normally, the original signal mask is restored.

   Once an action is installed for a specific signal, it remains
   installed until another action is explicitly requested (by
   another call to sigaction), until the SA_RESETHAND flag causes
   resetting of the handler, or until one of the exec functions is
   called.

   If the previous action for a specified signal had been
   established by signal, the values of the fields returned in
   the structure pointed to by the o_action argument of sigaction
   are unspecified, and in particular o_action->sa_handler is
   not necessarily the same value passed to signal. However, if a
   pointer to the same structure or a copy thereof is passed to a
   subsequent call to sigaction by means of the action argument
   of sigaction), the signal is handled as if the original call to
   signal were repeated.

   If sigaction fails, no new signal handler is installed.

   It is unspecified whether an attempt to set the action for a
   signal that cannot be intercepted or ignored to SIG_DFL is
   ignored or causes an error to be returned with errno set to
   EINVAL.

   See the "Error and Signal Handling" chapter of the HP C RTL
   Reference Manual for more information on signal handling.

                                  NOTE

      The sigvec and signal functions are provided for
      compatibility to old UNIX systems; their function is a
      subset of that available with the sigaction function.

   See also sigvec, signal, wait, read, and write.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; A new signal handler is
                      not installed. errno is set to one of the
                      following values:

                      o  EFAULT - The action or o_action argument
                         points to a location outside of the
                         allocated address space of the process.

                      o  EINVAL - The sig argument is not a valid
                         signal number. Or an attempt was made to
                         ignore or supply a handler for the SIGKILL,
                         SIGSTOP, and SIGCONT signals.
 

2  sigaddset
   Adds the specified individual signal.

   Format

     #include  <signal.h>

     int sigaddset  (sigset_t *set, int sig_number);
 

3  Arguments
 

set

   The signal set.
 

sig_number

   The individual signal.
 

3  Description
   The sigaddset function manipulates sets of signals. This function
   operates on data objects that you can address by the application,
   not on any set of signals known to the system. For example, this
   function does not operate on the set blocked from delivery to a
   process or the set pending for a process.

   The sigaddset function adds the individual signal specified by
   sig_number from the signal set specified by set.
 

3  Example

     The following example shows how to generate and use a signal
     mask that blocks only the SIGINT signal from delivery:

              #include <signal.h>
              int return_value;
              sigset_t newset;
                . . .
              sigemptyset(&newset);
              sigaddset(&newset, SIGINT);
              return_value = sigprocmask (SIG_SETMASK, &newset, NULL);
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to the
                      following value:

                      o  EINVAL - The value of sig_number is not a
                         valid signal number.
 

2  sigblock
   Adds the signals in mask to the current set of signals being
   blocked from delivery.

   Format

     #include  <signal.h>

     int sigblock  (int mask);
 

3  Argument
 

mask

   The signals to be blocked.
 

3  Description
   Signal i is blocked if the i - 1 bit in mask is a 1. For example,
   to add the protection-violation signal to the set of blocked
   signals, use the following line:

   sigblock(1 << (SIGBUS - 1));

   You can express signals in mnemonics (such as SIGBUS for a
   protection violation) or numbers as defined in the <signal.h>
   header file, and you can express combinations of signals by using
   the bitwise OR operator (|).
 

3  Return_Value

   x                  Indicates the previous set of masked signals.
 

2  sigdelset
   Deletes a specified individual signal.

   Format

     #include  <signal.h>

     int sigdelset  (sigset_t *set, int sig_number;)
 

3  Arguments
 

set

   The signal set.
 

sig_number

   The individual signal.
 

3  Description

   The sigdelset function deletes the individual signal specified by
   sig_number from the signal set specified by set.

   This function operates on data objects that you can address by
   the application, not on any set of signals known to the system.
   For example, this function does not operate on the set blocked
   from delivery to a process or the set pending for a process.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to the
                      following value:

                      o  EINVAL - The value of sig_number is not a
                         valid signal number.
 

2  sigemptyset
   Initializes the signal set to exclude all signals.

   Format

     #include  <signal.h>

     int sigemptyset  (sigset_t *set);
 

3  Argument
 

set

   The signal set.
 

3  Description
   The sigemptyset function initializes the signal set pointed to
   by set such that you exclude all signals. A call to sigemptyset
   or sigfillset must be made at least once for each object of type
   sigset_t prior to any other use of that object.

   This function operates on data objects that you can address by
   the application, not on any set of signals known to the system.
   For example, this function does not operate on the set blocked
   from delivery to a process or the set pending for a process.

   See also sigfillset.
 

3  Example

     The following example shows how to generate and use a signal
     mask that blocks only the SIGINT signal from delivery:

              #include <signal.h>
              int return_value;
              sigset_t newset;
                . . .
              sigemptyset(&newset);
              sigaddset(&newset, SIGINT);
              return_value = sigprocmask (SIG_SETMASK, &newset, NULL);
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; the global errno is set to
                      indicate the error.
 

2  sigfillset
   Initializes the signal set to include all signals.

   Format

     #include  <signal.h>

     int sigfillset  (sigset_t *set);
 

3  Argument
 

set

   The signal set.
 

3  Description
   The sigfillset function initializes the signal set pointed to
   by set such that you include all signals. A call to sigemptyset
   or sigfillset must be made at least once for each object of type
   sigset_t prior to any other use of that object.

   This function operates on data objects that you can address by
   the application, not on any set of signals known to the system.
   For example, this function does not operate on the set blocked
   from delivery to a process or the set pending for a process.

   See also sigemptyset.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to the
                      following value:

                      o  EINVAL - The value of the sig_number
                         argument is not a valid signal number.
 

2  sighold
   Adds the specified signal to the calling process's signal mask.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <signal.h>

     int sighold  (int signal);
 

3  Argument
 

signal

   The specified signal. The signal argument can be assigned any of
   the signals defined in the <signal.h> header file, except SIGKILL
   and SIGSTOP.
 

3  Description
   The sighold, sigrelse, and sigignore functions provide simplified
   signal management:

   o  The sighold function adds signal to the calling process's
      signal mask.

   o  The sigrelse function removes signal from the calling
      process's signal mask.

   o  The sigignore function sets the disposition of signal to SIG_
      IGN.

   The sighold function, in conjunction with sigrelse and sigpause,
   can be used to establish critical regions of code that require
   the delivery of a signal to be temporarily deferred.

   Upon success, the sighold function returns a value of 0.
   Otherwise, a value of -1 is returned, and errno is set to
   indicate the error.

                                  NOTE

      These interfaces are provided for compatibility only. New
      programs should use sigaction and sigprocmask to control the
      disposition of signals.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to the
                      following value:

                      o  EINVAL - The value of the signal argument
                         is either an invalid signal number or
                         SIGKILL.
 

2  sigignore
   Sets the disposition of the specified signal to SIG_IGN.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <signal.h>

     int sigignore  (int signal);
 

3  Argument
 

signal

   The specified signal. The signal argument can be assigned any of
   the signals defined in the <signal.h> header file, except SIGKILL
   and SIGSTOP.
 

3  Description
   The sighold, sigrelse, and sigignore functions provide simplified
   signal management:

   o  The sighold function adds signal to the calling process's
      signal mask.

   o  The sigrelse function removes signal from the calling
      process's signal mask.

   o  The sigignore function sets the disposition of signal to SIG_
      IGN.

   The sighold function, in conjunction with sigrelse and sigpause,
   can be used to establish critical regions of code that require
   the delivery of a signal to be temporarily deferred.

   Upon success, the sigignore function returns a value of 0.
   Otherwise, a value of -1 is returned, and errno is set to
   indicate the error.

                                  NOTE

      These interfaces are provided for compatibility only. New
      programs should use sigaction and sigprocmask to control the
      disposition of signals.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to the
                      following value:

                      o  EINVAL - The value of the signal argument
                         is either an invalid signal number or
                         SIGKILL, or an attempt is made to catch
                         a signal that cannot be intercepted or to
                         ignore a signal that cannot be ignored.
 

2  sigismember
   Tests whether a specified signal is a member of the signal set.

   Format

     #include  <signal.h>

     int sigismember  (const sigset_t *set, int sig_number);
 

3  Arguments
 

set

   The signal set.
 

sig_number

   The individual signal.
 

3  Description
   The sigismember function tests whether sig_number is a member of
   the signal set pointed to by set.

   This function operates on data objects that you can address by
   the application, not on any set of signals known to the system.
   For example, this function does not operate on the set blocked
   from delivery to a process or the set pending for a process.
 

3  Return_Values

   1                  Indicates success. The specified signal is a
                      member of the specified set.
   0                  Indicates an error. The specified signal is
                      not a member of the specified set.
 

2  siglongjmp
   Nonlocal goto with signal handling.

   Format

     #include  <setjmp.h>

     void siglongjmp  (sigjmp_buf env, int value);
 

3  Arguments
 

env

   An address for a sigjmp_buf structure.
 

value

   A nonzero value.
 

3  Description
   The siglongjmp function restores the environment saved by the
   most recent call to sigsetjmp in the same process with the
   corresponding sigjmp_buf argument.

   All accessible objects have values when siglongjmp is called,
   with one exception: values of objects of automatic storage
   duration that changed between the sigsetjmp call and siglongjmp
   call are indeterminate.

   Because it bypasses the usual function call and return
   mechanisms, siglongjmp executes correctly during interrupts,
   signals, and any of their associated functions. However, if you
   invoke siglongjmp from a nested signal handler (for example,
   from a function invoked as a result of a signal raised during the
   handling of another signal), the behavior is undefined.

   The siglongjmp function restores the saved signal mask only if
   you initialize the env argument by a call to sigsetjmp with a
   nonzero savemask argument.

   After siglongjmp is completed, program execution continues
   as if the corresponding call of sigsetjmp just returned the
   value specified by value. The siglongjmp function cannot cause
   sigsetjmp to return 0 (zero); if value is 0, sigsetjmp returns 1

   See also sigsetjmp.
 

2  sigmask
   Constructs the mask for a given signal number.

   Format

     #include  <signal.h>

     int sigmask  (signum);
 

3  Argument
 

signum

   The signal number for which the mask is to be constructed.
 

3  Description
   The sigmask function is used to construct the mask for a given
   signum. This mask can be used with the sigblock function.
 

3  Return_Value

   x                  The mask constructed for signum
 

2  signal
   Allows you to specify the way in which the signal sig is to be
   handled: use the default handling for the signal, ignore the
   signal, or call the signal handler at the address specified.

   Format

     #include  <signal.h>

     void  (*signal (int sig, void (*func) (int))) (int);
 

3  Arguments
 

sig

   The number or mnemonic associated with a signal. This argument
   is usually one of the mnemonics defined in the <signal.h> header
   file.
 

func

   Either the action to take when the signal is raised, or the
   address of a function needed to handle the signal.
 

3  Description
   If func is the constant SIG_DFL, the action for the given
   signal is reset to the default action, which is to terminate
   the receiving process. If the argument is SIG_IGN, the signal is
   ignored. Not all signals can be ignored.

   If func is neither SIG_DFL nor SIG_IGN, it specifies the address
   of a signal-handling function. When the signal is raised, the
   addressed function is called with sig as its argument. When the
   addressed function returns, the interrupted process continues
   at the point of interruption. (This is called catching a signal.
   Signals are reset to SIG_DFL after they are intercepted, except
   as shown in the Error and Signal Handling chapter of the HP C RTL
   Reference Manual.

   You must call the signal function each time you want to catch a
   signal.

   See the "Error and Signal Handling" chapter of the HP C RTL
   Reference Manual for more information on signal handling.

   To cause an OpenVMS exception or a signal to generate a UNIX
   style signal, OpenVMS condition handlers must return SS$_RESIGNAL
   upon receiving any exception that they do not want to handle.
   Returning SS$_CONTINUE prevents the correct generation of a UNIX
   style signal.
 

3  Return_Values

   x                  The address of the function previously
                      established to handle the signal.
   SIG_ERR            Indicates that the sig argument is out of
                      range.
 

2  sigpause
   Assigns mask to the current set of masked signals and then waits
   for a signal.

   Format

     #include  <signal.h>

     int sigpause  (int mask);
 

3  Argument
 

mask

   The signals to be blocked.
 

3  Description
   See the sigblock function for information about the mask
   argument.

   When control returns to sigpause, the function restores the
   previous set of masked signals, sets errno to EINTR, and returns
   -1 to indicate an interrupt. The value EINTR is defined in the
   <errno.h> header file.
 

3  Return_Value

   -1                 Indicates an interrupt. errno is set to EINTR.
 

2  sigpending
   Examines pending signals.

   Format

     #include  <signal.h>

     int sigpending  (sigset_t *set);
 

3  Argument
 

set

   A pointer to a sigset_t structure.
 

3  Description
   The sigpending function stores the set of signals that are
   blocked from delivery and pending to the calling process in the
   location pointed to by the set argument.

   Call either the sigemptyset or the sigfillset function at least
   once for each object of type sigset_t prior to any other use of
   that object. If you do not initialize an object in this way and
   supply an argument to the sigpending function, the result is
   undefined.

   See also sigemptyset and sigfillset in this section.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to the
                      following value:

                      o  SIGSEGV - Bad mask argument.
 

2  sigprocmask
   Sets the current signal mask.

   Format

     #include  <signal.h>

     int sigprocmask  (int how, const sigset_t *set, sigset_t *o_set);
 

3  Arguments
 

how

   An integer value that indicates how to change the set of masked
   signals. Use one of the following values:

   SIG_BLOCK     The resulting set is the union of the current set
                 and the signal set pointed to by the set argument.
   SIG_UNBLOCK   The resulting set is the intersection of the
                 current set and the complement of the signal set
                 pointed to by the set argument.
   SIG_SETMASK   The resulting set is the signal set pointed to by
                 the set argument.
 

set

   The signal set. If the value of the set argument is:

   o  Not NULL - It points to a set of signals used to change the
      currently blocked set.

   o  NULL - The value of the how argument is not significant, and
      the process signal mask is unchanged, so you can use the call
      to inquire about currently blocked signals.
 

o_set

   A non-NULL pointer to the location where the signal mask in
   effect at the time of the call is stored.
 

3  Description
   The sigprocmask function is used to examine or change the signal
   mask of the calling process.

   Typically, use the sigprocmask SIG_BLOCK value to block signals
   during a critical section of code, then use the sigprocmask SIG_
   SETMASK value to restore the mask to the previous value returned
   by the sigprocmask SIG_BLOCK value.

   If there are any unblocked signals pending after the call to the
   sigprocmask function, at least one of those signals is delivered
   before the sigprocmask function returns.

   You cannot block SIGKILL or SIGSTOP signals with the sigprocmask
   function. If a program attempts to block one of these signals,
   the sigprocmask function gives no indication of the error.
 

3  Example

     The following example shows how to set the signal mask to block
     only the SIGINT signal from delivery:

         #include <signal.h>

         int return_value;
         sigset_t newset;
          . . .
         sigemptyset(&newset);
         sigaddset(&newset, SIGINT);
         return_value = sigprocmask (SIG_SETMASK, &newset, NULL);
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error. The signal mask of the
                      process is unchanged. errno is set to one of
                      the following values:

                      o  EINVAL - The value of the how argument is
                         not equal to one of the defined values.

                      o  EFAULT - The set or o_set argument points
                         to a location outside the allocated address
                         space of the process.
 

2  sigrelse
   Removes the specified signal from the calling process's signal
   mask.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <signal.h>

     int sigrelse  (int signal);
 

3  Argument
 

signal

   The specified signal. The signal argument can be assigned any of
   the signals defined in the <signal.h> header file, except SIGKILL
   and SIGSTOP.
 

3  Description
   The sighold, sigrelse, and sigignore functions provide simplified
   signal management:

   o  The sighold function adds signal to the calling process's
      signal mask.

   o  The sigrelse function removes signal from the calling
      process's signal mask.

   o  The sigignore function sets the disposition of signal to SIG_
      IGN.

   The sighold function, in conjunction with sigrelse and sigpause,
   can be used to establish critical regions of code that require
   the delivery of a signal to be temporarily deferred.

   Upon success, the sigrelse function returns a value of 0.
   Otherwise, a value of -1 is returned, and errno is set to
   indicate the error.

                                  NOTE

      These interfaces are provided for compatibility only. New
      programs should use sigaction and sigprocmask to control the
      disposition of signals.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno is set to the
                      following value:

                      o  EINVAL - The value of the signal argument
                         is either an invalid signal number or
                         SIGKILL.
 

2  sigsetjmp
   Sets a jump point for a nonlocal goto.

   Format

     #include  <setjmp.h>

     init sigsetjmp  (sigjmp_buf env, int savemask);
 

3  Arguments
 

env

   An address for a sigjmp_buf structure.
 

savemask

   An integer value that specifies whether you need to save the
   current signal mask.
 

3  Description
   The sigsetjmp function saves its calling environment in its env
   argument for later use by the siglongjmp function.

   If the value of savemask is not 0 (zero), sigsetjmp also
   saves the process's current signal mask as part of the calling
   environment.

   See also siglongjmp.
 

3  Restrictions
   You cannot invoke the longjmp function from an OpenVMS condition
   handler. However, you may invoke longjmp from a signal handler
   that has been established for any signal supported by the
   Compaq C RTL, subject to the following nesting restrictions:

   o  The longjmp function will not work if you invoke it from
      nested signal handlers. The result of the longjmp function,
      when invoked from a signal handler that has been entered as a
      result of an exception generated in another signal handler, is
      undefined.

   o  Do not invoke the sigsetjmp function from a signal handler
      unless the associated longjmp is to be issued before the
      handling of that signal is completed.

   o  Do not invoke the longjmp function from within an exit handler
      (established with atexit or SYS$DCLEXH). Exit handlers are
      invoked after image tear-down, so the destination address of
      the longjmp no longer exists.

   o  Invoking longjmp from within a signal handler to return to
      the main thread of execution might leave your program in
      an inconsistent state. Possible side effects include the
      inability to perform I/O or to receive any more UNIX signals.
      Use siglongjmp instead.
 

3  Return_Values

   0                  Indicates success.
   nonzero            The return is a call to the siglongjmp
                      function.
 

2  sigsetmask
   Establishes those signals that are blocked from delivery.

   Format

     #include  <signal.h>

     int sigsetmask  (int mask);
 

3  Argument
 

mask

   The signals to be blocked.
 

3  Description
   See the sigblock function for information about the mask
   argument.
 

3  Return_Value

   x                  The previous set of masked signals.
 

2  sigsuspend
   Atomically changes the set of blocked signals and waits for a
   signal.

   Format

     #include  <signal.h>

     int sigsuspend  (const sigset_t *signal_mask);
 

3  Argument
 

signal_mask

   A pointer to a set of signals.
 

3  Description
   The sigsuspend function replaces the signal mask of the process
   with the set of signals pointed to by the signal_mask argument.
   Then it suspends execution of the process until delivery of
   a signal whose action is either to execute a signal catching
   function or to terminate the process. You cannot block the
   SIGKILL or SIGSTOP signals with the sigsuspend function. If a
   program attempts to block either of these signals, sigsuspend
   gives no indication of the error.

   If delivery of a signal causes the process to terminate,
   sigsuspend does not return. If delivery of a signal causes a
   signal catching function to execute, sigsuspend returns after the
   signal catching function returns, with the signal mask restored
   to the set that existed prior to the call to sigsuspend.

   The sigsuspend function sets the signal mask and waits for
   an unblocked signal as one atomic operation. This means that
   signals cannot occur between the operations of setting the mask
   and waiting for a signal. If a program invokes sigprocmask SIG_
   SETMASK and sigsuspend separately, a signal that occurs between
   these functions is often not noticed by sigsuspend.

   In normal usage, a signal is blocked by using the sigprocmask
   function at the beginning of a critical section. The process then
   determines whether there is work for it to do. If there is no
   work, the process waits for work by calling sigsuspend with the
   mask previously returned by sigprocmask.

   If a signal is intercepted by the calling process and control
   is returned from the signal handler, the calling process resumes
   execution after sigsuspend, which always returns a value of -1
   and sets errno to EINTR.

   See also sigpause and sigprocmask.
 

2  sigtimedwait
   Suspends a calling thread and waits for queued signals to arrive.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <signal.h>

     int sigtimedwait  (const sigset_t set, siginfo_t *info, const    
                       struct timespec *timeout);
 

3  Arguments
 

set

   The set of signals to wait for.
 

info

   Pointer to a siginfo structure that is receiving data describing
   the signal, including any application-defined data specified when
   the signal was posted.
 

timeout

   A timeout for the wait. If timeout is NULL, the argument is
   ignored.
 

3  Description
   The sigtimedwait function behaves the same as the sigwaitinfo
   function except that if none of the signals specified by set are
   pending, sigtimedwait waits for the time interval specified in
   the timespec structure referenced by timeout. If the timespec
   structure pointed to by timeout is zero-valued and if none of the
   signals specified by set are pending, then sigtimedwait returns
   immediately with an error.

   See also sigwait and sigwaitinfo.

   See the "Error and Signal Handling" chapter of the HP C RTL
   Reference Manual for more information on signal handling.
 

3  Return_Values

   x                  Upon successful completion, the signal number
                      selected is returned.
   -1                 Indicates that an error occurred; errno is set
                      to one of the following values:

                      o  EINVAL - The timeout argument specified a
                         tv_nsec value less than 0 or greater than
                         or equal to 1 billion.

                      o  EINTR - The wait was interrupted by an
                         unblocked, intercepted signal.

                      o  EAGAIN - No signal specified by set was
                         generated within the specified timeout
                         period.
 

2  sigvec
   Permanently assigns a handler for a specific signal.

   Format

     #include  <signal.h>

     int sigvec  (int sigint, struct sigvec *sv, struct sigvec *osv);
 

3  Arguments
 

sigint

   The signal identifier.
 

sv

   Pointer to a sigvec structure (see the Description section).
 

osv

   If osv is not NULL, the previous handling information for the
   signal is returned.
 

3  Description
   If sv is not NULL, it specifies the address of a structure
   containing a pointer to a handler routine and mask to be used
   when delivering the specified signal, and a flag indicating
   whether the signal is to be processed on an alternative stack.
   If sv->onstack has a value of 1, the system delivers the signal
   to the process on a signal stack specified with sigstack.

   The sigvec function establishes a handler that remains
   established until explicitly removed or until the image
   terminates.

   The sigvec structure is defined in the <signal.h> header file:

   struct sigvec
      {
         int   (*handler)();
         int   mask;
         int   onstack;
      };

   See the "Error and Signal Handling" chapter of the HP C RTL
   Reference Manual for more information on signal handling.
 

3  Return_Values

   0                  Indicates that the call succeeded.
   -1                 Indicates that an error occurred.
 

2  sigwait
   Suspends a calling thread and waits for queued signals to arrive.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <signal.h>

     int sigwait  (const sigset_t set, int *sig);
 

3  Arguments
 

set

   The set of signals to wait for.
 

sig

   Returns the signal number of the selected signal.
 

3  Description
   The sigwait function suspends the calling thread until at least
   one of the signals in the set argument is in the caller's set
   of pending signals. When this happens, one of those signals
   is automatically selected and removed from the set of pending
   signals. The signal number identifying that signal is then
   returned in the location referenced by sig.

   The effect is unspecified if any signals in the set argument are
   not blocked when the sigwait function is called.

   The set argument is created using the set manipulation functions
   sigemptyset, sigfillset, sigaddset, and sigdelset.

   If, while the sigwait function is waiting, a signal occurs that
   is eligible for delivery (that is, not blocked by the signal
   mask), that signal is handled asynchronously and the wait is
   interrupted.

   See also sigtimedwait and sigwaitinfo.

   See the "Error and Signal Handling" chapter of the HP C RTL
   Reference Manual for more information on signal handling.
 

3  Return_Values

   0                  Upon successful completion, sigwait stores the
                      signal number of the received signal at the
                      location referenced by sig and returns 0.
   nonzero            Indicates that an error occurred; errno is set
                      to the following value:

                      o  EINVAL - The set argument contains an
                         invalid or unsupported signal number.
 

2  sigwaitinfo
   Suspends a calling thread and waits for queued signals to arrive.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <signal.h>

     int sigwaitinfo  (const sigset_t set, siginfo_t *info);
 

3  Arguments
 

set

   The set of signals to wait for.
 

info

   Pointer to a siginfo structure that is receiving data describing
   the signal, including any application-defined data specified when
   the signal was posted.
 

3  Description
   The sigwaitinfo function behaves the same as the sigwait function
   if the info argument is NULL.

   If the info argument is non-NULL, the sigwaitinfo function
   behaves the same as sigwait, except that the selected signal
   number is stored in the si_signo member of the siginfo structure,
   and the cause of the signal is stored in the si_code member.
   If any value is queued to the selected signal, the first such
   queued value is dequeued and the value is stored in the si_value
   member of info. The system resource used to queue the signal is
   released and made available to queue other signals. If no value
   is queued, the content of the si_value member is undefined. If no
   further signals are queued for the selected signal, the pending
   indication for that signal is reset.

   See also sigtimedwait and sigwait.

   See the "Error and Signal Handling" chapter of the HP C RTL
   Reference Manual for more information on signal handling.
 

3  Return_Values

   x                  Upon successful completion, the signal number
                      selected is returned.
   -1                 Indicates that an error occurred; errno is set
                      to one of the following values:

                      o  EINVAL - The set argument contains an
                         invalid or unsupported signal number.

                      o  EINTR - The wait was interrupted by an
                         unblocked, intercepted signal.
 

2  sin
   Returns the sine of its radian argument.

   Format

     #include  <math.h>

     double sin  (double x);

     float sinf  (float x); (Integrity servers, Alpha)

     long double sinl  (long double x); (Integrity servers, Alpha)

     double sind  (double x); (Integrity servers, Alpha)

     float sindf  (float x); (Integrity servers, Alpha)

     long double sindl  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A radian expressed as a floating-point number.
 

3  Description
   The sin functions compute the sine of x measured in radians.

   The sind functions compute the sine of x measured in degrees.
 

3  Return_Values

   x                  The sine of the argument.
   NaN                x = Infinity or NaN; errno is set to EDOM.
   0                  Underflow occurred; errno is set to ERANGE.
 

2  sinh
   Returns the hyperbolic sine of its argument.

   Format

     #include  <math.h>

     double sinh  (double x);

     float sinhf  (float x); (Integrity servers, Alpha)

     long double sinhl  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A real number.
 

3  Return_Values

   n                  The hyperbolic sine of the argument.
   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
   0                  Underflow occurred; errno is set to ERANGE.
   NaN                x is NaN; errno is set to EDOM.
 

2  sleep
   Suspends the execution of the current process (or thread in a
   threaded program) for at least the number of seconds indicated by
   its argument.

   Format

     #include  <unistd.h>

     unsigned int sleep  (unsigned seconds); (_DECC_V4_SOURCE)

     int sleep  (unsigned seconds); (not _DECC_V4_SOURCE)
 

3  Argument
 

seconds

   The number of seconds.
 

3  Description
   The sleep function sleeps for the specified number of seconds, or
   until a signal is received, or until the process (or thread in a
   threaded program) executes a call to SYS$WAKE.

   If a SIGALRM signal is generated, but blocked or ignored, the
   sleep function returns. For all other signals, a blocked or
   ignored signal does not cause sleep to return.
 

3  Return_Values

   x                  The number of seconds that the process awoke
                      early.
   0                  If the process slept the full number of
                      seconds specified by seconds.
 

2  snprintf
   Performs formatted output to a string in memory.

   Format

     #include  <stdio.h>

     int snprintf  (char *str, size_t n, const char           
                   *format_spec, . . . );
 

3  Arguments
 

str

   The address of the string that will receive the formatted output.
 

n

   The size of the buffer referred to by str.
 

format_spec

   A pointer to a character string that contains the format
   specification.
 

 . . .

   Optional expressions whose resultant types correspond to
   conversion specifications given in the format specification.

   If no conversion specifications are given, you may omit the
   output sources. Otherwise, the function calls must have at least
   as many output sources as there are conversion specifications,
   and the conversion specifications must match the types of the
   output sources.

   Conversion specifications are matched to output sources in left-
   to-right order. Excess output pointers, if any, are ignored.
 

3  Description
   The snprintf function is identical to the sprintf function with
   the addition of the n argument, which specifies the size of the
   buffer referred to by str.

   On successful completion, snprintf returns the number of bytes
   (excluding the terminating null byte) that would be written to
   str if n is sufficiently large.

   If n is 0, nothing is written, the number of bytes (excluding the
   terminating null) that would be written if n were sufficiently
   large are returned, and str might be a NULL pointer. Otherwise,
   output bytes beyond the n - 1st are discarded instead of being
   written to the array, and a null byte is written at the end of
   the bytes actually written into the array.

   If an output error is encountered, a negative value is returned.
 

3  Return_Values

   x                  The number of bytes (excluding the terminating
                      null byte) that would be written to str if n
                      is sufficiently large.
   Negative value     Indicates an output error occurred. The
                      function sets errno. For a list of errno
                      values set by this function, see fprintf.
 

2  sprintf
   Performs formatted output to a string in memory.

   Format

     #include  <stdio.h>

     int sprintf  (char *str, const char *format_spec, . . . );
 

3  Arguments
 

str

   The address of the string that will receive the formatted output.
   It is assumed that this string is large enough to hold the
   output.
 

format_spec

   A pointer to a character string that contains the format
   specification.
 

 . . .

   Optional expressions whose resultant types correspond to
   conversion specifications given in the format specification.

   If no conversion specifications are given, you may omit the
   output sources. Otherwise, the function calls must have at least
   as many output sources as there are conversion specifications,
   and the conversion specifications must match the types of the
   output sources.

   Conversion specifications are matched to output sources in left-
   to-right order. Excess output pointers, if any, are ignored.
 

3  Description
   The sprintf function places output followed by the null character
   (\0) in consecutive bytes starting at *str. The user must ensure
   that enough space is available.

   Consider the following example of a conversion specification:

   #include <stdio.h>

   main()
   {
      int  temp = 4, temp2 = 17;
      char s[80];

      sprintf(s, "The answers are %d, and %d.", temp, temp2);
   }

   In this example, character string s has the following contents:

   The answers are 4, and 17.
 

3  Return_Values

   x                  The number of characters placed in the
                      output string, not including the final null
                      character.
   Negative value     Indicates an output error occurred. The
                      function sets errno. For a list of errno
                      values set by this function, see fprintf.
 

2  sqrt
   Returns the square root of its argument.

   Format

     #include  <math.h>

     double sqrt  (double x);

     float sqrtf  (float x); (Integrity servers, Alpha)

     long double sqrtl  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A real number.
 

3  Return_Values

   val                The square root of x, if x is nonnegative.
   0                  x is negative; errno is set to EDOM.
   NaN                x is NaN; errno is set to EDOM.
 

2  srand
   Initializes the pseudorandom-number generator rand.

   Format

     #include  <stdlib.h>

     void srand  (unsigned int seed);
 

3  Argument
 

seed

   An unsigned integer.
 

3  Description
   The srand function uses the argument as a seed for a new sequence
   of pseudorandom numbers to be returned by subsequent calls to
   rand.

   If srand is then called with the same seed value, the sequence of
   pseudorandom numbers is repeated.

   If rand is called before any calls to srand, the same sequence of
   pseudorandom numbers is generated as when srand is first called
   with a seed value of 1.
 

2  srand48
   Initializes a 48-bit random-number generator.

   Format

     #include  <stdlib.h>

     void srand48  (long int seed_val);
 

3  Argument
 

seed_val

   The initialization value to begin randomization. Changing this
   value changes the randomization pattern.
 

3  Description
   The srand48 function initializes the random-number generator. You
   can use this function in your program before calling the drand48,
   lrand48, or mrand48 functions. (Although it is not recommended
   practice, constant default initializer values are automatically
   supplied if you call drand48, lrand48, or mrand48 without calling
   an initialization function).

   The function works by generating a sequence of 48-bit integer
   values, Xi, according to the linear congruential formula:

          Xn+1 = (aXn+c)mod m        n >= 0

   The argument m equals 248, so 48-bit integer arithmetic is

   performed. Unless you invoke the lcong48 function, the multiplier
   value a and the addend value c are:

         a = 5DEECE66D16 = 2736731631558

         c = B16 = 138

   The initializer function srand48 sets the high-order 32 bits
   of Xi to the low-order 32 bits contained in its argument. The
   low-order 16 bits of Xi are set to the arbitrary value 330E16.

   See also drand48, lrand48, and mrand48.
 

2  srandom
   Initializes the pseudorandom-number generator random.

   Format

     #include  <stdlib.h>

     int srandom  (unsigned seed);
 

3  Argument
 

seed

   An initial seed value.
 

3  Description
   The srandom function uses the argument as a seed for a new
   sequence of pseudorandom numbers to be returned by subsequent
   calls to random. This function has virtually the same calling
   sequence and initialization properties as the srand function, but
   produce sequences that are more random.

   The srandom function initializes the current state with the
   initial seed value. The srandom function, unlike the srand
   function, does not return the old seed because the amount of
   state information used is more than a single word.

   See also rand, srand, random, setstate, and initstate.
 

3  Return_Values

   0                  Indicates success. Initializes the state seed.
   -1                 Indicates an error, further specified in the
                      global errno.
 

2  sscanf
   Reads input from a character string in memory, interpreting it
   according to the format specification.

   Format

     #include  <stdio.h>

     int sscanf  (const char *str, const char *format_spec, . . . );
 

3  Arguments
 

str

   The address of the character string that provides the input text
   to sscanf.
 

format_spec

   A pointer to a character string that contains the format
   specification.
 

 . . .

   Optional expressions whose resultant types correspond to
   conversion specifications given in the format specification.

   If no conversion specifications are given, you can omit the input
   pointers. Otherwise, the function calls must have at least as
   many input pointers as there are conversion specifications, and
   the conversion specifications must match the types of the input
   pointers.

   Conversion specifications are matched to input sources in left-
   to-right order. Excess input pointers, if any, are ignored.
 

3  Description
   The following is an example of a conversion specification:

   main ()
   {
      char str[] = "4 17";
      int   temp,
            temp2;

      sscanf(str, "%d %d", &temp, &temp2);
      printf("The answers are %d and %d.", temp, temp2);
   }

   This example produces the following output:

   $ RUN  EXAMPLE
   The answers are 4 and 17.
 

3  Return_Values

   x                  The number of successfully matched and
                      assigned input items.
   EOF                Indicates that a read error occurred before
                      any conversion. The function sets errno. For a
                      list of the values set by this function, see
                      fscanf.
 

2  ssignal
   Allows you to specify the action to take when a particular signal
   is raised.

   Format

     #include  <signal.h>

     void  (*ssignal (int sig, void (*func) (int, . . . )))   
           (int, . . . );
 

3  Arguments
 

sig

   A number or mnemonic associated with a signal. The symbolic
   constants for signal values are defined in the <signal.h> header
   file. See the Error and Signal Handling chapter of the HP C RTL
   Reference Manual.
 

func

   The action to take when the signal is raised, or the address of a
   function that is executed when the signal is raised.
 

3  Description
   The ssignal function is equivalent to the signal function except
   for the return value on error conditions.

   Since the signal function is defined by the ANSI C standard and
   the ssignal function is not, use signal for greater portability.

   See the "Error and Signal Handling" chapter of the HP C RTL
   Reference Manual for more information on signal handling.
 

3  Return_Values

   x                  The address of the function previously
                      established as the action for the signal.
                      The address may be the value SIG_DFL (0)  or
                      SIG_IGN (1).
   0                  Indicates errors. For this reason, there is
                      no way to know whether a return status of 0
                      indicates failure, or whether it indicates
                      that a previous action was SIG_DFL (0).
 

2  [w]standend
   Deactivate the boldface attribute for the specified window. The
   standend function operates on the stdscr window.

   Format

     #include  <curses.h>

     int standend  (void);

     int wstandend  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Description
   The standend and wstandend functions are equivalent to clrattr
   and wclrattr called with the attribute _BOLD.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  [w]standout
   Activate the boldface attribute of the specified window. The
   standout function acts on the stdscr window.

   Format

     #include  <curses.h>

     int standout  (void);

     int wstandout  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Description
   The standout and wstandout functions are equivalent to setattr
   and wsetattr called with the attribute _BOLD.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  stat
   Accesses information about the specified file.

   Format

     #include  <stat.h>

     int stat  (const char *file_spec, struct stat *buffer); 
               (ISO POSIX-1)

     int stat  (const char *file_spec, struct stat *buffer, . . . );
               (DEC C Extension)
 

3  Function_Variants
   Compiling with the _DECC_V4_SOURCE and _VMS_V6_SOURCE feature-
   test macros defined enables a local-time-based entry point to the
   stat function that is equivalent to the behavior before OpenVMS
   Version 7.0.

   Compiling with the _USE_STD_STAT feature-test macro defined
   enables a variant of the stat function that uses an X/Open
   standard-compliant definition of the stat structure. The _USE_
   STD_STAT feature-test macro is mutually exclusive with the _DECC_
   V4_SOURCE and _VMS_V6_SOURCE macros.
 

3  Arguments
 

file_spec

   A valid OpenVMS or UNIX style file specification (no wildcards).
   Read, write, or execute permission of the named file is not
   required, but you must be able to reach all directories listed
   in the file specification leading to the file.
 

buffer

   A pointer to a structure of type stat. For convenience, a typedef
   stat_t is defined as struct stat in the <stat.h> header file.

   This argument receives information about the particular file. The
   members of the structure pointed to by buffer are described in
   the Description section.
 

 . . .

   An optional default file-name string.

   This is the only optional RMS keyword that can be specified for
   the stat function. See the description of the creat function for
   the full list of optional RMS keywords and their values.
 

3  Description
   When the _USE_STD_STAT feature-test macro is not enabled, the
   legacy stat structure is used. When _USE_STD_STAT is enabled, the
   X/Open standard-compliant stat structure is used.

   Legacy stat Structure

   With the _USE_STD_STAT feature-test macro defined to DISABLE, the
   following legacy stat structure is used:

   Member       Type        Definition

   st_dev       dev_t       Pointer to the physical device name
   st_ino[3]    ino_t       Three words to receive the file ID
   st_mode      mode_t      File "mode" (prot, dir, . . . )
   st_nlink     nlink_t     For UNIX system compatibility only
   st_uid       uid_t       Owner user ID
   st_gid       gid_t       Group member: from st_uid
   st_rdev      dev_t       UNIX system compatibility - always 0
   st_size      off_t       File size, in bytes. For st_size to
                            report a correct value, you need to
                            flush both the C RTL and RMS buffers.
   st_atime     time_t      File access time; always the same as
                            st_mtime
   st_mtime     time_t      Last modification time
   st_ctime     time_t      File creation time
   st_fab_rfm   char        Record format
   st_fab_rat   char        Record attributes
   st_fab_fsz   char        Fixed header size
   st_fab_mrs   unsigned    Record size

   The types dev_t, ino_t, off_t, mode_t, nlink_t, uid_t, gid_t, and
   time_t, are defined in the <stat.h> header file. However, when
   compiling for compatibility (/DEFINE=_DECC_V4_SOURCE), only dev_
   t, ino_t, and off_t are defined.

   The off_t data type is either a 32-bit or 64-bit integer. The 64-
   bit interface allows for file sizes greater than 2 GB, and can be
   selected at compile time by defining the _LARGEFILE feature-test
   macro as follows:

   CC/DEFINE=_LARGEFILE

   As of OpenVMS Version 7.0, times are given in seconds since the
   Epoch (00:00:00 GMT, January 1, 1970).

   The st_mode structure member is the status information mode
   defined in the <stat.h> header file. The st_mode bits are
   described as follows:

   Bits     Constant   Definition

   0170000  S_IFMT     Type of file
   0040000  S_IFDIR    Directory
   0020000  S_IFCHR    Character special
   0060000  S_IFBLK    Block special
   0100000  S_IFREG    Regular
   0030000  S_IFMPC    Multiplexed char special
   0070000  S_IFMPB    Multiplexed block special
   0004000  S_ISUID    Set user ID on execution
   0002000  S_ISGID    Set group ID on execution
   0001000  S_ISVTX    Save swapped text even after use
   0000400  S_IREAD    Read permission, owner
   0000200  S_IWRITE   Write permission, owner
   0000100  S_IEXEC    Execute/search permission, owner

   The stat function does not work on remote network files.

   If the file is a record file, the st_size field includes
   carriage-control information. Consequently, the st_size value
   will not correspond to the number of characters that can be read
   from the file.

   Also be aware that for st_size to report a correct value, you
   need to flush both the C RTL and RMS buffers.

   Standard-Compliant stat Structure

   With OpenVMS Version 8.2, the _USE_STD_STAT feature-test macro
   and standard-compliant stat structure are introduced in support
   of UNIX compatibility.

   With _USE_STD_STAT defined to ENABLE, you get the following
   behavior:

   o  Old struct stat definitions

      Old definitions of struct stat are obsolete. You must
      recompile your applications to access the new features.
      Existing applications will continue to access the old
      definitions and functions unless they are recompiled to use
      the new features.

   o  Function variants

      Calls to stat, fstat, lstat, and ftw accept pointers to
      structures of the new type. Calls to these functions are
      mapped to the new library entries __std_stat, __std_fstat,
      __std_lstat, and __std_ftw,  respectively.

   o  Compatibilities with other feature macros

      _DECC_V4_SOURCE source-code compatibility is not supported.
      You must not enable _DECC_V4_SOURCE and _USE_STD_STAT at the
      same time.

      _VMS_V6_SOURCE binary compatibility is not supported. You must
      not enable _VMS_V6_SOURCE and _USE_STD_STAT at the same time.
      As a result, only UTC (rather than local-time) is supported
      for the time_t fields.

   o  Type changes

      The following type changes are in effect:

      -  32-bit gid type gid_t is used. _DECC_SHORT_GID_T is
         unsupported.

      -  _LARGEFILE offsets are used. off_t is forced to 64 bits.

      -  Type ino_t, representing the file number, is an unsigned
         int quadword (64 bits). Previously, it was an unsigned
         short.

      -  Type dev_t, representing the device id, is an unsigned int
         quadword (64 bits). Previously, it was a 32-bit character
         pointer. The new type is standard because it is arithmetic.

      -  Types blksize_t and blkcnt_t are added and defined as
         unsigned int quadwords (64 bits).

   o  Structure member Changes

      -  Two members are added to struct stat:

         blksize_t   st_blksize;
         blkcnt_t    st_blocks;

         According to the X/Open standard, st_blksize is the
         filesystem-specific preferred I/O blocksize for this file.
         On OpenVMS systems, st_blksize is set to the device buffer
         size multiplied by the disk cluster size. st_blocks is set
         to the allocated size of the file, in blocks. The blocksize
         used to calculate st_blocks is not necessarily the same as
         st_blksize and, in most cases, will not be the same.

      -  In struct stat, member st_ino is of type ino_t. In previous
         C RTL versions, it was of type ino_t [3] (array of 3 ino_
         t). Since ino_t has changed from a word to a quadword,
         the size of this member has increased by one word. The
         principal significance of this change is that it makes st_
         ino a scalar, which is how most open source applications
         define it.

      -  The new definition of ino_t also affects applications
         that include the <dirent.h> header file. In struct dirent,
         member d_ino changes in the same way as the st_ino member
         of struct stat in <stat.h>.

      -  Several macros that are not part of any standard were
         introduced in <stat.h> to facilitate access to the
         constituent parts of ino_t values:

            S_INO_NUM(ino), S_INO_SEQ(ino), and S_INO_RVN(ino)
            return the FILES-11 file number, sequence number, and
            relative volume number of ino, respectively, as unsigned
            shorts.

            S_INO_RVN_RVN(ino) returns the byte of the RVN field
            containing the relative volume number;

            S_INO_RVN_NMX(ino) returns the byte of the RVN field
            containing the file number extension.

         Although individual components can be broken out like this,
         they are not part of the X/Open standard and should not be
         relied on in portable applications.

   o  Semantic changes

      Values of type dev_t are now unique for each device across
      clusters. An algorithm based on device name and allocation
      class or SCSSYSTEMID (for single-pathed devices) calculates
      the device id value having these characteristics, an X/Open
      standard requirement. Typically, the combination of file
      number and device id uniquely identifies a file in a cluster.

      This change affects stat structure members st_dev and st_rdev.
      For compatibility with previous releases, st_rdev is set to
      either 0 or st_dev.

                    NOTE (Integrity servers, Alpha)

      On OpenVMS Alpha and Integrity server systems, the stat,
      fstat, utime, and utimes functions have been enhanced to
      take advantage of the new file-system support for POSIX
      compliant file timestamps.

      This support is available only on ODS-5 devices on OpenVMS
      Alpha systems beginning with a version of OpenVMS Alpha
      after Version 7.3.

      Before this change, the stat and fstat functions were
      setting the values of the st_ctime, st_mtime, and st_atime
      fields based on the following file attributes:

         st_ctime - ATR$C_CREDATE (file creation time)
         st_mtime - ATR$C_REVDATE (file revision time)
         st_atime - was always set to st_mtime because no support
         for file access time was available

      Also, for the file-modification time, utime and utimes were
      modifying the ATR$C_REVDATE file attribute, and ignoring the
      file-access-time argument.

      After the change, for a file on an ODS-5 device, the stat
      and fstat functions set the values of the st_ctime, st_
      mtime, and st_atime fields based on the following new file
      attributes:

         st_ctime - ATR$C_ATTDATE (last attribute modification
         time)
         st_mtime - ATR$C_MODDATE (last data modification time)
         st_atime - ATR$C_ACCDATE (last access time)

      If ATR$C_ACCDATE is zero, as on an ODS-2 device, the stat
      and fstat functions set st_atime to st_mtime.

      For the file-modification time, the utime and utimes
      functions modify both the ATR$C_REVDATE and ATR$C_MODDATE
      file attributes. For the file-access time, these functions
      modify the ATR$C_ACCDATE file attribute. Setting the ATR$C_
      MODDATE and ATR$C_ACCDATE file attributes on an ODS-2 device
      has no effect.

      For compatibility, the old behavior of stat, fstat, utime,
      and utimes remains the default, regardless of the kind of
      device.

      The new behavior must be explicitly enabled by defining
      the DECC$EFS_FILE_TIMESTAMPS logical name to ENABLE before
      invoking the application. Setting this logical does not
      affect the behavior of stat, fstat, utime, and utimes for
      files on an ODS-2 device.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error other than a privilege
                      violation; errno is set to indicate the error.
   -2                 Indicates a privilege violation.
 

2  statvfs
   Gets information about a device containing the specified file.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <statvfs.h>

     int statvfs  (const char *restrict path, struct statvfs        
                  *restrict buffer);
 

3  Arguments
 

path

   Any file on a mounted device.
 

buffer

   Pointer to a statvfs structure to hold the returned information.
 

3  Description
   The statvfs function returns descriptive information about the
   device containing the specified file. Read, write, or execute
   permission of the specified file is not required. The returned
   information is in the format of a statvfs structure, which is
   defined in the <statvfs.h> header file and contains the following
   members:

      unsigned long f_bsize - Preferred block size.

      unsigned long f_frsize - Fundamental block size.

      fsblkcnt_t f_blocks - Total number of blocks in units of f_
      frsize.

      fsblkcnt_t f_bfree - Total number of free blocks. If f_bfree
      would assume a meaningless value due to the misreporting of
      free block count by $GETDVI for a DFS disk, then f_bfree is
      set to the maximum block count.

      fsblkcnt_t f_bavail - Number of free blocks available. Set to
      the unused portion of the caller's disk quota.

      fsfilcnt_t f_files - Total number of file serial numbers (for
      example, inodes).

      fsfilcnt_t f_ffree - Total number of free file serial
      numbers. For OpenVMS systems, this value is calculated as
      freeblocks/clustersize.

      fsfilcnt_t f_favail - Number of file serial numbers available
      to a non-privileged process (0 for OpenVMS systems).

      unsigned long f_fsid - File system identifier. This identifier
      is based on the allocation-class device name. This gives a
      unique value based on device, as long as the device is locally
      mounted.

      unsigned long f_flag - Bit mask representing one or more of
      the following flags:

         ST_RONLY - The volume is read-only.
         ST_NOSUID - The volume has protected subsystems enabled.

      unsigned long f_namemax - Maximum length of a filename.
      char f_basetype[64] - Device-type name.
      char f_fstr[64] - Logical volume name.
      char __reserved[64] - Media type name.

   Upon successful completion, statvfs returns 0 (zero). Otherwise,
   it returns -1 and sets errno to indicate the error.

   See also fstatvfs.
 

3  Return_Value

   0                  Successful completion.
   -1                 Indicates an error. errno is set to one of the
                      following:

                      o  EACCES - Search permission is denied for a
                         component of the path prefix.

                      o  EIO - An I/O error occurred while reading
                         the device.

                      o  EINTR - A signal was intercepted during
                         execution of the function.

                      o  EOVERFLOW - One of the values to be
                         returned cannot be represented correctly
                         in the structure pointed to by buffer.

                      o  ENAMETOOLONG - The length of a component
                         of the path parameter exceeds NAME_MAX, or
                         the length of the path parameter exceeds
                         PATH_MAX.

                      o  ENOENT - A component of path does not
                         name an existing file, or path is an empty
                         string.

                      o  ENOTDIR - A component of the path prefix of
                         the path parameter is not a directory.
 

2  strcasecmp
   Does a case-insensitive comparison of two 7-bit ASCII strings.

   Format

     #include  <strings.h>

     int strcasecmp  (const char *s1, const char *s2);
 

3  Arguments
 

s1

   The first of two strings to compare.
 

s2

   The second of two strings to compare.
 

3  Description
   The strcasecmp function is case-insensitive. The returned
   lexicographic difference reflects a conversion to lowercase.

   The strcasecmp function works for 7-bit ASCII compares only. Do
   not use this function for internationalized applications.
 

3  Return_Value

   n                  An integer value greater than, equal to, or
                      less than 0 (zero), depending on whether the
                      s1 string is greater than, equal to, or less
                      than the s2 string.
 

2  strcat
   Concatenates str_2, including the terminating null character, to
   the end of str_1.

   Format

     #include  <string.h>

     char *strcat  (char *str_1, const char *str_2);
 

3  Function_Variants
   The strcat function has variants named _strcat32 and _strcat64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

str_1, str_2

   Pointers to null-terminated character strings.
 

3  Description
   See strncat.
 

3  Return_Value

   x                  The address of the first argument, str_1,
                      which is assumed to be large enough to hold
                      the concatenated result.
 

3  Example

       #include <string.h>
       #include <stdio.h>

       /* This program concatenates two strings using the strcat       */
       /* function, and then manually compares the result of strcat    */
       /* to the expected result.                                      */

       #define S1LENGTH 10
       #define S2LENGTH 8

       main()
       {
           static char s1buf[S1LENGTH + S2LENGTH] = "abcmnexyz";
           static char s2buf[] = " orthis";
           static char test1[] = "abcmnexyz orthis";

           int i;
           char *status;

           /* Take static buffer s1buf, concatenate static buffer      */
           /* s2buf to it, and compare the answer in s1buf with the    */
           /* static answer in test1.                                  */

           status = strcat(s1buf, s2buf);
           for (i = 0; i <= S1LENGTH + S2LENGTH - 2; i++) {
               /* Check for correct returned string.   */

               if (test1[i] != s1buf[i])
                   printf("error in strcat");
           }
       }
 

2  strchr
   Returns the address of the first occurrence of a given character
   in a null-terminated string.

   Format

     #include  <string.h>

     char *strchr  (const char *str, int character);
 

3  Function_Variants
   The strchr function has variants named _strchr32 and _strchr64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

str

   A pointer to a null-terminated character string.
 

character

   An object of type int.
 

3  Description
   This function returns the address of the first occurrence of a
   given character in a null-terminated string. The terminating null
   character is considered to be part of the string.

   Compare with strrchr, which returns the address of the last
   occurrence of a given character in a null-terminated string.
 

3  Return_Values

   x                  The address of the first occurrence of the
                      specified character.
   NULL               Indicates that the character does not occur in
                      the string.
 

3  Example

       #include <stdio.h>
       #include <string.h>

       main()
       {

           static char s1buf[] = "abcdefghijkl lkjihgfedcba";

           int i;

           char *status;

       /*  This program checks the strchr function by incrementally   */
       /*  going through a string that ascends to the middle and then */
       /*  descends towards the end.                                  */

           for (i = 0; s1buf[i] != '\0' && s1buf[i] != ' '; i++) {
               status = strchr(s1buf, s1buf[i]);

       /* Check for pointer to leftmost character - test 1.           */

               if (status != &s1buf[i])
                   printf("error in strchr");
           }
       }
 

2  strcmp
   Compares two ASCII character strings and returns a negative,
   0, or positive integer, indicating that the ASCII values of the
   individual characters in the first string are less than, equal
   to, or greater than the values in the second string.

   Format

     #include  <string.h>

     int strcmp  (const char *str_1, const char *str_2);
 

3  Arguments
 

str_1, str_2

   Pointers to character strings.
 

3  Description
   The strings are compared until a null character is encountered or
   until the strings differ.
 

3  Return_Values

   < 0                Indicates that str_1 is less than str_2.
   = 0                Indicates that str_1 equals str_2.
   > 0                Indicates that str_1 is greater than str_2.
 

2  strcoll
   Compares two strings and returns an integer that indicates if
   the strings differ and how they differ. The function uses the
   collating information in the LC_COLLATE category of the current
   locale to determine how the comparison is performed.

   Format

     #include  <string.h>

     int strcoll  (const char *s1, const char *s2);
 

3  Arguments
 

s1, s2

   Pointers to character strings.
 

3  Description
   The strcoll function, unlike strcmp, compares two strings in a
   locale-dependent manner. Because no value is reserved for error
   indication, the application must check for one by setting errno
   to 0 before the function call and testing it after the call.

   See also strxfrm.
 

3  Return_Values

   < 0                Indicates that s1 is less than s2.
   = 0                Indicates that the strings are equal.
   > 0                Indicates that s1 is greater than s2.
 

2  strcpy
   Copies all of source, including the terminating null character,
   into dest.

   Format

     #include  <string.h>

     char *strcpy  (char *dest, const char *source);
 

3  Function_Variants
   The strcpy function has variants named _strcpy32 and _strcpy64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

dest

   Pointer to the destination character string.
 

source

   Pointer to the source character string.
 

3  Description
   The strcpy function copies source into dest, and stops after
   copying source's null character.

   The behavior of this function is undefined if the area pointed to
   by dest overlaps the area pointed to by source.
 

3  Return_Value

   x                  The address of dest.
 

2  strcspn
   Returns the length of the prefix of a string that consists
   entirely of characters not in a specified set of characters.

   Format

     #include  <string.h>

     size_t strcspn  (const char *str, const char *charset);
 

3  Arguments
 

str

   A pointer to a character string. If this character string is a
   null string, 0 is returned.
 

charset

   A pointer to a character string containing the set of characters.
 

3  Description
   The strcspn function scans the characters in the string, stops
   when it encounters a character found in charset, and returns the
   length of the string's initial segment formed by characters not
   found in charset.

   If none of the characters match in the character strings pointed
   to by str and charset, strcspn returns the length of string.
 

3  Return_Value

   x                  The length of the segment.
 

2  strdup
   Duplicates the specified string.

   Format

     #include  <string.h>

     char *strdup  (const char *s1);
 

3  Function_Variants
   The strdup function has variants named _strdup32 and _strdup64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Argument
 

s1

   The string to be duplicated.
 

3  Description
   The strdup function returns a pointer to a string that is an
   exact duplicate of the string pointed to by s1. The malloc
   function is used to allocate space for the new string. The strdup
   function is provided for compatibility with existing systems.
 

3  Return_Values

   x                  A pointer to the resulting string.
   NULL               Indicates an error.
 

2  strerror
   Maps the error number in error_code to a locale-dependent error
   message string.

   Format

     #include  <string.h>

     char *strerror  (int error_code); (ANSI C)

     char *strerror  (int error_code[, int vms_error_code]); 
                     (DEC C Extension)
 

3  Arguments
 

error_code

   An error code.
 

vms_error_code

   An OpenVMS error code.
 

3  Description
   The strerror function uses the error number in error_code to
   retrieve the appropriate locale-dependent error message. The
   contents of the error message strings are determined by the LC_
   MESSAGES category of the program's current locale.

   When a program is not compiled with any standards-related
   feature-test macros, strerror has a second argument (vms_error_
   code), which is used in the following way:

   o  If error_code is EVMSERR and there is a second argument, then
      that second argument is used as the vaxc$errno value.

   o  If error_code is EVMSERR and there is no second argument, look
      at vaxc$errno to get the OpenVMS error condition.

   See the Example section.

   Use of the second argument is not included in the ANSI C
   definition of strerror and is, therefore, not portable.

   Because no return value is reserved to indicate an error,
   applications should set the value of errno to 0, call strerror,
   and then test the value of errno; a nonzero value indicates an
   error condition.
 

3  Return_Value

   x                  A pointer to a buffer containing the
                      appropriate error message. Do not modify
                      this buffer in your programs. Moreover, calls
                      to the strerror function may overwrite this
                      buffer with a new message.
 

3  Example

       #include <stdio.h>
       #include <errno.h>
       #include <string.h>
       #include <stdlib.h>
       #include <ssdef.h>

       main()
       {
           puts(strerror(EVMSERR));
           errno = EVMSERR;
           vaxc$errno = SS$_LINKEXIT;
           puts(strerror(errno));
           puts(strerror(EVMSERR, SS$_ABORT));
           exit(1);
       }

   Running this example produces the following output:

   nontranslatable vms error code: <none>
   network partner exited
   abort
 

2  strfmon
   Converts a number of monetary values into a string. The
   conversion is controlled by a format string.

   Format

     #include  <monetary.h>

     ssize_t strfmon  (char *s, size_t maxsize, const char     
                      *format, . . . );
 

3  Arguments
 

s

   A pointer to the resultant string.
 

maxsize

   The maximum number of bytes to be stored in the resultant string.
 

format

   A pointer to a string that controls the format of the output
   string.
 

 . . .

   The monetary values of type double that are to be formatted for
   the output string. There should be as many values as there are
   conversion specifications in the format string pointed to by
   format. The function fails if there are insufficient values.
   Excess arguments are ignored.
 

3  Description
   The strfmon function creates a string pointed to by s, using the
   monetary values supplied. A maximum of maxsize bytes is copied to
   s.

   The format string pointed to by format consists of ordinary
   characters and conversion specifications. All ordinary characters
   are copied unchanged to the output string. A conversion
   specification defines how one of the monetary values supplied
   is formatted in the output string.

   A conversion specification consists of a percent character
   (%), followed by a number of optional characters (see Optional
   Characters in strfmon Conversion Specifications), and concluding
   with a conversion specifier (see strfmon Conversion Specifiers).

   If any of the optional characters listed in Optional Characters
   in strfmon Conversion Specifications is included in a conversion
   specification, they must appear in the order shown.

   Table REF-5 Optional Characters in strfmon Conversion
               Specifications

   Character     Meaning

   =character    Use character as the numeric fill character if a
                 left precision is specified. The default numeric
                 fill character is the space character. The fill
                 character must be representable as a single byte
                 in order to work with precision and width count.
                 This conversion specifier is ignored unless a
                 left precision is specified, and it does not
                 affect width filling, which always uses the space
                 character.
   ^             Do not use separator characters to format the
                 number. By default, the digits are grouped
                 according to the mon_grouping field in the LC_
                 MONETARY category of the current locale.
   +             Add the string specified by the positive_sign
                 or negative_sign fields in the current locale.
                 If p_sign_posn or n_sign_posn is set to 0, then
                 parentheses are used by default to indicate
                 negative values. Otherwise, sign strings are used
                 to indicate the sign of the value. You cannot use a
                 + and a ( in the same conversion specification.
   (             Enclose negative values within parentheses. The
                 default is taken from the p_sign_posn and n_sign_
                 posn fields in the current locale. If p_sign_
                 posn or n_sign_posn is set to 0, then parentheses
                 are used by default to indicate negative values.
                 Otherwise, sign strings are used to indicate the
                 sign of the value. You cannot use a + and ( in the
                 same conversion specification.
   !             Suppress the currency symbol. By default, the
                 currency symbol is included.
   -             Left-justify the value within the field. By
                 default, values are right-justified.
   field width   A decimal integer that specifies the minimum
                 field width in which to align the result of the
                 conversion. The default field width is the smallest
                 field that can contain the result.
   #left_        A # followed by a decimal integer specifies
   precision     the number of digits to the left of the radix
                 character. Extra positions are filled by the
                 fill character. By default the precision is the
                 smallest required for the argument. If grouping
                 is not suppressed with the ^ conversion specifier,
                 and if grouping is defined for the current locale,
                 grouping separators are inserted before any fill
                 characters are added. Grouping separators are
                 not applied to fill characters even if the fill
                 character is defined as a digit.
   .right_       A period (.) followed by a decimal integer
   precision     specifies the number of digits to the right of
                 the radix character. Extra positions are filled
                 with zeros. The amount is rounded to this number
                 of decimal places. If the right precision is zero,
                 the radix character is not included in the output.
                 By default the right precision is defined by the
                 frac_digits or int_frac_digits field of the current
                 locale.

   Table REF-6 strfmon Conversion Specifiers

   SpecifierMeaning

   i        Use the international currency symbol defined by the
            int_currency_symbol field in the current locale, unless
            the currency symbol has been suppressed.
   n        Use the local currency symbol defined by the currency_
            symbol field in the current locale, unless the currency
            symbol has been suppressed.
   %        Output a % character. The conversion specification must
            be %%; none of the optional characters is valid with
            this specifier.
 

3  Return_Values

   x                  The number of bytes written to the string
                      pointed to by s, not including the null-
                      terminating character.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      o  EINVAL - A conversion specification is
                         syntactically incorrect.

                      o  E2BIG - Processing the complete format
                         string would produce more than maxsize
                         bytes.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <locale.h>
       #include <monetary.h>
       #include <errno.h>

       #define MAX_BUF_SIZE 124

       main()
       {
         size_t ret;
         char buffer[MAX_BUF_SIZE];
         double amount = 102593421;

        /* Display a monetary amount using the en_US.ISO8859-1 */
        /* locale and a range of different display formats.    */

         if (setlocale(LC_ALL, "en_US.ISO8859-1") == (char *) NULL) {
             perror("setlocale");
             exit(EXIT_FAILURE);
         }
         ret = strfmon(buffer, MAX_BUF_
SIZE, "International: %i\n", amount);
         printf(buffer);

         ret = strfmon(buffer, MAX_BUF_
SIZE, "National:      %n\n", amount);
         printf(buffer);

         ret = strfmon(buffer, MAX_BUF_
SIZE, "National:      %=*#10n\n", amount);
         printf(buffer);

         ret = strfmon(buffer, MAX_BUF_
SIZE, "National:     %(n\n", -1 * amount);
         printf(buffer);

         ret = strfmon(buffer, MAX_BUF_
SIZE, "National:      %^!n\n", amount);
         printf(buffer);
       }

   Running the example program produces the following result:

   International: USD 102,593,421.00
   National:      $102,593,421.00
   National:      $**102,593,421.00
   National:      ($102,593,421.00)
   National:      102593421.00
 

2  strftime
   Uses date and time information stored in a tm structure to create
   an output string. The format of the output string is controlled
   by a format string.

   Format

     #include  <time.h>

     size_t strftime  (char *s, size_t maxsize, const char *format,
                      const struct tm *timeptr);
 

3  Function_Variants
   Compiling with the _DECC_V4_SOURCE and _VMS_V6_SOURCE feature-
   test macros defined enables a local-time-based entry point to
   the strftime function that is equivalent to the behavior before
   OpenVMS Version 7.0.
 

3  Arguments
 

s

   A pointer to the resultant string.
 

maxsize

   The maximum number of bytes to be stored in the resultant string,
   including the null terminator.
 

format

   A pointer to a string that controls the format of the output
   string.
 

timeptr

   A pointer to the local time (tm) structure. The tm structure is
   defined in the <time.h> header file.
 

3  Description
   The strftime function uses data in the structure pointed to
   by timeptr to create the string pointed to by s. A maximum of
   maxsize bytes is copied to s.

   The format string consists of zero or more conversion
   specifications and ordinary characters. All ordinary characters
   (including the terminating null character) are copied unchanged
   into the output string. A conversion specification defines how
   data in the tm structure is formatted in the output string.

   A conversion specification consists of a percent (%) character
   followed by one or more optional characters (see Optional
   Elements of strftime Conversion Specifications), and concluding
   with a conversion specifier (see strftime Conversion Specifiers).
   If any of the optional characters listed in Optional Elements
   of strftime Conversion Specifications are specified, they must
   appear in the order shown in the table.

   The strftime function behaves as if it called tzset.

   Table REF-7 Optional Elements of strftime Conversion
               Specifications

   Element    Meaning

   -          Optional with the field width to specify that the field
              is left-justified and padded with spaces. This cannot
              be used with the 0 element.
   0          Optional with the field width to specify that the field
              is right-justified and padded with zeros. This cannot
              be used with the - element.
   field      A decimal integer that specifies the maximum field
   width      width
   .precision A decimal integer that specifies the precision of data
              in a field.

              For the d, H, I, j, m, M, o, S, U, w, W, y, and Y
              conversion specifiers, the precision specifier is the
              minimum number of digits to appear in the field. If
              the conversion specification has fewer digits than that
              specified by the precision, leading zeros are added.

              For the a, A, b, B, c, D, E, h, n, N, p, r, t, T,
              x, X, Z, and % conversion specifiers, the precision
              specifier is the maximum number of characters to appear
              in the field. If the conversion specification has
              more characters than that specified by the precision,
              characters are truncated on the right.

              The default precision for the d, H, I, m, M, o, S, U,
              w, W, y and Y conversion specifiers is 2; the default
              precision for the j conversion specifier is 3.

   Note that the list of conversion specifications in Optional
   Elements of strftime Conversion Specifications are extensions
   to the XPG4 specification.

   strftime Conversion Specifiers lists the conversion specifiers.
   The strftime function uses fields in the LC_TIME category of
   the program's current locale to provide a value. For example, if
   %B is specified, the function accesses the mon field in LC_TIME
   to find the full month name for the month specified in the tm
   structure. The result of using invalid conversion specifiers is
   undefined.

   Table REF-8 strftime Conversion Specifiers

   Specifier  Replaced by

   a          The locale's abbreviated weekday name
   A          The locale's full weekday name
   b          The locale's abbreviated month name
   B          The locale's full month name
   c          The locale's appropriate date and time representation
   C          The century number (the year divided by 100 and
              truncated to an integer) as a decimal number (00 -
              99)
   d          The day of the month as a decimal number (01 - 31)
   D          Same as %m/%d/%y
   e          The day of the month as a decimal number (1 - 31) in a
              2-digit field with the leading space character fill
   Ec         The locale's alternative date and time representation
   EC         The name of the base year (period) in the locale's
              alternative representation
   Ex         The locale's alternative date representation
   EX         The locale's alternative time representation
   Ey         The offset from the base year (%EC) in the locale's
              alternative representation
   EY         The locale's full alternative year representation
   h          Same as %b
   H          The hour (24-hour clock) as a decimal number (00 - 23)
   I          The hour (12-hour clock) as a decimal number (01 - 12)
   j          The day of the year as a decimal number (001 - 366)
   m          The month as a decimal number (01 - 12)
   M          The minute as a decimal number (00 - 59)
   n          The new-line character
   Od         The day of the month using the locale's alternative
              numeric symbols
   Oe         The date of the month using the locale's alternative
              numeric symbols
   OH         The hour (24-hour clock) using the locale's alternative
              numeric symbols
   OI         The hour (12-hour clock) using the locale's alternative
              numeric symbols
   Om         The month using the locale's alternative numeric
              symbols
   OM         The minutes using the locale's alternative numeric
              symbols
   OS         The seconds using the locale's alternative numeric
              symbols
   Ou         The weekday as a number in the locale's alternative
              representation (Monday=1)
   OU         The week number of the year (Sunday as the first day
              of the week) using the locale's alternative numeric
              symbols
   OV         The week number of the year (Monday as the first day
              of the week) as a decimal number (01 - 53) using the
              locale's alternative numeric symbols. If the week
              containing January 1 has four or more days in the
              new year, it is considered as week 1. Otherwise, it
              is considered as week 53 of the previous year, and the
              next week is week 1.
   Ow         The weekday as a number (Sunday=0) using the locale's
              alternative numeric symbols
   OW         The week number of the year (Monday as the first day
              of the week) using the locale's alternative numeric
              symbols
   Oy         The year without the century using the locale's
              alternative numeric symbols
   p          The locale's equivalent of the AM/PM designations
              associated with a 12-hour clock
   r          The time in AM/PM notation
   R          The time in 24-hour notation (%H:%M)
   S          The second as a decimal number (00 - 61)
   t          The tab character
   T          The time (%H:%M:%S)
   u          The weekday as a decimal number between 1 and 7
              (Monday=1)
   U          The week number of the year (the first Sunday as the
              first day of week 1) as a decimal number (00 - 53)
   V          The week number of the year (Monday as the first day
              of the week) as a decimal number (00 - 53). If the
              week containing January 1 has four or more days in the
              new year, it is considered as week 1. Otherwise, it
              is considered as week 53 of the previous year, and the
              next week is week 1.
   w          The weekday as a decimal number (0 [Sunday] - 6)
   W          The week number of the year (the first Monday as the
              first day of week 1) as a decimal number (00 - 53)
   x          The locale's appropriate date representation
   X          The locale's appropriate time representation
   y          The year without century as a decimal number (00 - 99)
   Y          The year with century as a decimal number
   Z          Time-zone name or abbreviation. If time-zone
              information is not available, no character is output.
   %          Literal % character.
 

3  Return_Values

   x                  The number of characters placed into the array
                      pointed to by s, not including the terminating
                      null character.
   0                  Indicates an error occurred. The contents of
                      the array are indeterminate.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <time.h>
       #include <locale.h>
       #include <errno.h>

       #define NUM_OF_DATES  7
       #define BUF_SIZE 256

       /* This program formats a number of different dates, once */
       /* using the C locale and then using the fr_FR.ISO8859-1  */
       /* locale. Date and time formatting is done using strftime(). */

       main()
       {
           int count,
               i;
           char buffer[BUF_SIZE];
           struct tm *tm_ptr;
           time_t time_list[NUM_OF_DATES] =
           {500, 68200000, 694223999, 694224000,
            704900000, 705000000, 705900000};

           /* Display dates using the C locale */
           printf("\nUsing the C locale:\n\n");

           setlocale(LC_ALL, "C");

           for (i = 0; i < NUM_OF_DATES; i++) {
               /* Convert to a tm structure */
               tm_ptr = localtime(&time_list[i]);

               /* Format the date and time */
               count = strftime(buffer, BUF_SIZE,
                      "Date: %A %d %B %Y%nTime: %T%n%n", tm_ptr);
               if (count == 0) {
                   perror("strftime");
                   exit(EXIT_FAILURE);
               }

               /* Print the result */
              printf(buffer);
           }

           /* Display dates using the fr_FR.ISO8859-1 locale */
           printf("\nUsing the fr_FR.ISO8859-1 locale:\n\n");

           setlocale(LC_ALL, "fr_FR.ISO8859-1");

           for (i = 0; i < NUM_OF_DATES; i++) {
               /* Convert to a tm structure */
               tm_ptr = localtime(&time_list[i]);

               /* Format the date and time */
               count = strftime(buffer, BUF_SIZE,
                      "Date: %A %d %B %Y%nTime: %T%n%n", tm_ptr);
               if (count == 0) {
                   perror("strftime");
                   exit(EXIT_FAILURE);
               }

               /* Print the result */
               printf(buffer);
           }
       }

   Running the example program produces the following result:

   Using the C locale:

   Date: Thursday 01 January 1970
   Time: 00:08:20

   Date: Tuesday 29 February 1972
   Time: 08:26:40

   Date: Tuesday 31 December 1991
   Time: 23:59:59

   Date: Wednesday 01 January 1992
   Time: 00:00:00

   Date: Sunday 03 May 1992
   Time: 13:33:20

   Date: Monday 04 May 1992
   Time: 17:20:00

   Date: Friday 15 May 1992
   Time: 03:20:00

   Using the fr_FR.ISO8859-1 locale:

   Date: jeudi 01 janvier 1970
   Time: 00:08:20

   Date: mardi 29 février 1972
   Time: 08:26:40

   Date: mardi 31 décembre 1991
   Time: 23:59:59

   Date: mercredi 01 janvier 1992
   Time: 00:00:00

   Date: dimanche 03 mai 1992
   Time: 13:33:20

   Date: lundi 04 mai 1992
   Time: 17:20:00

   Date: vendredi 15 mai 1992
   Time: 03:20:00
 

2  strlen
   Returns the length of a string of ASCII characters. The returned
   length does not include the terminating null character (\0).

   Format

     #include  <string.h>

     size_t strlen  (const char *str);
 

3  Argument
 

str

   A pointer to the character string.
 

3  Return_Value

   x                  The length of the string.
 

2  strncasecmp
   Does a case-insensitive comparison between two 7-bit ASCII
   strings.

   Format

     #include  <strings.h>

     int strncasecmp  (const char *s1, const char *s2, size_t n);
 

3  Arguments
 

s1

   The first of two strings to compare.
 

s2

   The second of two strings to compare.
 

n

   The maximum number of bytes in a string to compare.
 

3  Description
   The strncasecmp function is case-insensitive. The returned
   lexicographic difference reflects a conversion to lowercase.
   The strncasecmp function is similar to the strcasecmp function,
   but also compares size. If the size specified by n is read before
   a NULL, the comparison stops.

   The strcasecmp function works for 7-bit ASCII compares only. Do
   not use this function for internationalized applications.
 

3  Return_Value

   n                  An integer value greater than, equal to, or
                      less than 0 (zero), depending on whether s1 is
                      greater than, equal to, or less than s2.
 

2  strncat
   Appends not more than maxchar characters from str_2 to the end of
   str_1.

   Format

     #include  <string.h>

     char *strncat  (char *str_1, const char *str_2, size_t        
                    maxchar);
 

3  Function_Variants
   The strncat function has variants named _strncat32 and _strncat64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

str_1, str_2

   Pointers to null-terminated character strings.
 

maxchar

   The number of characters to concatenate from str_2, unless
   strncat first encounters a null terminator in str_2. If maxchar
   is 0, no characters are copied from str_2.
 

3  Description
   A null character is always appended to the result of the strncat
   function. If strncat reaches the specified maximum, it sets the
   next byte in str_1 to the null character.
 

3  Return_Value

   x                  The address of the first argument, str_1,
                      which is assumed to be large enough to hold
                      the concatenated result.
 

2  strncmp
   Compares not more than maxchar characters of two ASCII character
   strings and returns a negative, 0, or positive integer,
   indicating that the ASCII values of the individual characters
   in the first string are less than, equal to, or greater than the
   values in the second string.

   Format

     #include  <string.h>

     int strncmp  (const char *str_1, const char *str_2, size_t    
                  maxchar);
 

3  Arguments
 

str_1, str_2

   Pointers to character strings.
 

maxchar

   The maximum number of characters (beginning with the first) to
   search in both str_1 and str_2. If maxchar is 0, no comparison is
   performed and 0 is returned (the strings are considered equal).
 

3  Description
   The strncmp function compares no more than maxchar characters
   from the string pointed to by str_1 to the string pointed
   to by str_2. The strings are compared until a null character
   is encountered, the strings differ, or maxchar is reached.
   Characters that follow a difference or a null character are not
   compared.
 

3  Return_Values

   < 0                Indicates that str_1 is less than str_2.
   = 0                Indicates that str_1 equals str_2.
   > 0                Indicates that str_1 is greater than str_2.
 

3  Examples

   1.#include <string.h>

     #include <stdio.h>

     main()
     {
         printf( "%d\n", strncmp("abcde", "abc", 3));
     }

     When linked and executed, this example returns 0, because the
     first 3 characters of the 2 strings are equal:

       $ run tmp
       0

   2.#include <string.h>

     #include <stdio.h>

         main()
         {
             printf( "%d\n", strncmp("abcde", "abc", 4));
         }

     When linked and executed, this example returns a value greater
     than 0 because the first 4 characters of the 2 strings are not
     equal (The "d" in the first string is not equal to the null
     character in the second):

       $ run tmp
               100
 

2  strncpy
   Copies not more than maxchar characters from source into dest.

   Format

     #include  <string.h>

     char *strncpy  (char *dest, const char *source, size_t        
                    maxchar);
 

3  Function_Variants
   The strncpy function has variants named _strncpy32 and _strncpy64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

dest

   Pointer to the destination character string.
 

source

   Pointer to the source character string.
 

maxchar

   The maximum number of characters to copy from source to dest up
   to but not including the null terminator of source.
 

3  Description
   The strncpy function copies no more than maxchar characters from
   source to dest, up to but not including the null terminator of
   source. If source contains less than maxchar characters, dest
   is padded with null characters. If source contains greater than
   or equal to maxchar characters, as many characters as possible
   are copied to dest. Be aware that the dest argument might not be
   terminated by a null character after a call to strncpy.
 

3  Return_Value

   x                  The address of dest.
 

2  strnlen
   Returns the number of bytes in a string.

   Format

     #include  <string.h>

     size_t strnlen  (const char *s, size_t n);
 

3  Arguments
 

s

   Pointer to the string.
 

n

   The maximum number of characters to examine.
 

3  Description
   The strnlen function returns the number of bytes in the string
   pointed to by s. The string length value does not include the
   terminating null character. The strnlen function counts bytes
   until the first null byte or until n bytes have been examined.
 

3  Return_Value

   n                  The length of the string.
 

2  strpbrk
   Searches a string for the occurrence of one of a specified set of
   characters.

   Format

     #include  <string.h>

     char *strpbrk  (const char *str, const char *charset);
 

3  Function_Variants
   The strpbrk function has variants named _strpbrk32 and _strpbrk64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

str

   A pointer to a character string. If this character string is a
   null string, 0 is returned.
 

charset

   A pointer to a character string containing the set of characters
   for which the function will search.
 

3  Description
   The strpbrk function scans the characters in the string, stops
   when it encounters a character found in charset, and returns the
   address of the first character in the string that appears in the
   character set.
 

3  Return_Values

   x                  The address of the first character in the
                      string that is in the set.
   NULL               Indicates that no character is in the set.
 

2  strptime
   Converts a character string into date and time values that are
   stored in a tm structure. Conversion is controlled by a format
   string.

   Format

     #include  <time.h>

     char *strptime  (const char *buf, const char *format, struct tm
                     *timeptr);
 

3  Function_Variants
   The strptime function has variants named _strptime32 and _
   strptime64 for use with 32-bit and 64-bit pointer sizes,
   respectively.
 

3  Arguments
 

buf

   A pointer to the character string to convert.
 

format

   A pointer to the string that defines how the input string is
   converted.
 

timeptr

   A pointer to the local time structure. The tm structure is
   defined in the <time.h> header file.
 

3  Description
   The strptime function converts the string pointed to by buf into
   values that are stored in the structure pointed to by timeptr.
   The string pointed to by format defines how the conversion is
   performed.

   The strptime function modifies only those fields in the tm
   structure that have corresponding conversion specifications
   in the format. In particular, strptime never sets the tm_isdst
   member of the tm structure.

   The format string consists of zero or more directives. A
   directive is composed of one of the following:

   o  One or more white-space characters (as defined by the isspace
      function). This directive causes the function to read input up
      to the first character that is not a white-space character.

   o  Any character other than the percent character (%) or a white-
      space character. This directive causes the function to read
      the next character. The character read must be the same as the
      character that comprises the directive. If the character is
      different, the function fails.

   o  A conversion specification. A conversion specification defines
      how characters in the input string are interpreted as values
      that are then stored in the tm structure. A conversion
      specification consists of a percent (%) character followed
      by a conversion specifier. strptime Conversion Specifications
      lists the valid conversion specifications.

   The strptime function uses fields in the LC_TIME category of the
   program's current locale to provide a value.

                                  NOTE

      To be compliant with X/Open CAE Specification System
      Interfaces and Headers Issue 5 (commonly known as XPG5), the
      strptime function processes the "%y" directive differently
      than in previous versions of the HP C RTL.

      With Version 6.4 and higher of the C compiler, for a two-
      digit year within the century if no century is specified,
      "%y" directive values range from:

      o  69 to 99 refer to years in the twentieth century (1969 to
         1999 inclusive)

      o  00 to 68 refer to years in the twenty-first century (2000
         to 2068 inclusive)

      In previous (XPG4-compliant) versions of the HP C RTL,
      strptime interpreted a two-digit year with no century
      specified as a year within the twentieth century.

      The XPG5-compliant strptime is now the default version in
      the HP C RTL.

      To obtain the old, XPG4-compliant strptime function
      behavior, specify one of the following:

      o  Define the DECC$XPG4_STRPTIME logical name as follows:

         $ DEFINE DECC$XPG4_STRPTIME ENABLE

         or:

      o  Call the XPG4 strptime directly as the function
         decc$strptime_xpg4.

      To return to using the XPG5 strptime version, DEASSIGN the
      DECC$XPG4_STRPTIME logical name:

      $ DEASSIGN DECC$XPG4_STRPTIME

   Table REF-9 strptime Conversion Specifications

   SpecificaReplaced by

   %a       The weekday name. This is either the abbreviated or the
            full name.
   %A       Same as %a.
   %b       The month name. This is either the abbreviated or the
            full name.
   %B       Same as %b.
   %c       The date and time using the locale's date format.
   %Ec      The locale's alternative date and time representation.
   %C       The century number (the year divided by 100 and
            truncated to an integer) as a decimal number (00 - 99).
            Leading zeros are permitted.
   %EC      The name of the base year (period) in the locale's
            alternative representation.
   %d       The day of the month as a decimal number (01 - 31).
            Leading zeros are permitted.
   %Od      The day of the month using the locale's alternative
            numeric symbols.
   %D       Same as %m/%d/%y.
   %e       Same as %d.
   %Oe      The date of the month using the locale's alternative
            numeric symbols.
   %h       Same as %b.
   %H       The hour (24-hour clock) as a decimal number (00 - 23).
            Leading zeros are permitted.
   %OH      The hour (24-hour clock) using the locale's alternative
            numeric symbols.
   %I       The hour (12-hour clock) as a decimal number (01 - 12).
            Leading zeros are permitted.
   %OI      The hour (12-hour clock) using the locale's alternative
            numeric symbols.
   %j       The day of the year as a decimal number (001 - 366).
   %m       The month as a decimal number (01 - 12). Leading zeros
            are permitted.
   %Om      The month using the locale's alternative numeric
            symbols.
   %M       The minute as a decimal number (00 - 59). Leading zeros
            are permitted.
   %OM      The minutes using the locale's alternative numeric
            symbols.
   %n       Any white-space character.
   %p       The locale's equivalent of the AM/PM designations
            associated with a 12-hour clock.
   %r       The time in AM/PM notation (%I:%M:%S %p).
   %R       The time in 24-hour notation (%H:%M).
   %S       The second as a decimal number (00 - 61). Leading zeros
            are permitted.
   %OS      The seconds using the locale's alternative numeric
            symbols.
   %t       Any white-space character.
   %T       The time (%H:%M:%S).
   %U       The week number of the year (the first Sunday as the
            first day of week 1) as a decimal number (00 - 53).
            Leading zeros are permitted.
   %OU      The week number of the year (Sunday as the first day
            of the week) using the locale's alternative numeric
            symbols.
   %w       The weekday as a decimal number (0 [Sunday] - 6).
            Leading zeros are permitted.
   %Ow      The weekday as a number (Sunday=0) using the locale's
            alternative numeric symbols.
   %W       The week number of the year (the first Monday as the
            first day of week 1) as a decimal number (00 - 53).
            Leading zeros are permitted.
   %OW      The week number of the year (Monday as the first day
            of the week) using the locale's alternative numeric
            symbols.
   %x       The locale's appropriate date representation.
   %Ex      The locale's alternative date representation.
   %EX      The locale's alternative time representation.
   %X       The locale's appropriate time representation.
   %y       The year without century as a decimal number (00 - 99).
   %Ey      The offset from the base year (%EC) in the locale's
            alternative representation.
   %Oy      The year without the century using the locale's
            alternative numeric symbols.
   %Y       The year with century as a decimal number.
   %EY      The locale's full alternative year representation.
   %%       Literal % character.
 

3  Return_Values

   x                  A pointer to the character following the last
                      character parsed.
   NULL               Indicates that an error occurred. The contents
                      of the tm structure are undefined.
 

3  Example

       #include <string.h>
       #include <stdlib.h>
       #include <stdio.h>
       #include <time.h>
       #include <locale.h>
       #include <errno.h>

       #define NUM_OF_DATES  7
       #define BUF_SIZE 256

       /* This program takes a number of date and time strings and     */
       /* converts them into tm structs using strptime().  These tm    */
       /* structs are then passed to strftime() which will reverse the */
       /* process.  The resulting strings are then compared with the   */
       /* originals and if a difference is found then an error is      */
       /* displayed.                                                   */

       main()
       {
       int count,
           i;
       char buffer[BUF_SIZE];
       char *ret_val;
       struct tm time_struct;
       char dates[NUM_OF_DATES][BUF_SIZE] =
       {
           "Thursday 01 January 1970 00:08:20",
           "Tuesday 29 February 1972 08:26:40",
           "Tuesday 31 December 1991 23:59:59",
           "Wednesday 01 January 1992 00:00:00",
           "Sunday 03 May 1992 13:33:20",
           "Monday 04 May 1992 17:20:00",
           "Friday 15 May 1992 03:20:00"};

       for (i = 0; i < NUM_OF_DATES; i++) {
           /* Convert to a tm structure */
        ret_val = strptime(dates[i], "%A %d %B %Y %T", &time_struct);

           /* Check the return value */
           if (ret_val == (char *) NULL) {
               perror("strptime");
               exit(EXIT_FAILURE);
           }

           /* Convert the time structure back to a formatted string */
       count = strftime(buffer, BUF_SIZE, "%A %d %B %Y %T",&time_struct);

           /* Check the return value */
           if (count == 0) {
               perror("strftime");
               exit(EXIT_FAILURE);
           }

           /* Check the result */
           if (strcmp(buffer, dates[i]) != 0) {
           printf("Error: Converted string differs from the original\n");
           }
           else {
               printf("Successfully converted <%s>\n", dates[i]);
           }
        }
       }

   Running the example program produces the following result:

   Successfully converted <Thursday 01 January 1970 00:08:20>
   Successfully converted <Tuesday 29 February 1972 08:26:40>
   Successfully converted <Tuesday 31 December 1991 23:59:59>
   Successfully converted <Wednesday 01 January 1992 00:00:00>
   Successfully converted <Sunday 03 May 1992 13:33:20>
   Successfully converted <Monday 04 May 1992 17:20:00>
   Successfully converted <Friday 15 May 1992 03:20:00>
 

2  strrchr
   Returns the address of the last occurrence of a given character
   in a null-terminated string.

   Format

     #include  <string.h>

     char *strrchr  (const char *str, int character);
 

3  Function_Variants
   The strrchr function has variants named _strrchr32 and _strrchr64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

str

   A pointer to a null-terminated character string.
 

character

   An object of type int.
 

3  Description
   This function returns the address of the last occurrence of a
   given character in a null-terminated string. The terminating null
   character is considered to be part of the string.

   Compare with strchr, which returns the address of the first
   occurrence of a given character in a null-terminated string.
 

3  Return_Values

   x                  The address of the last occurrence of the
                      specified character.
   NULL               Indicates that the character does not occur in
                      the string.
 

2  strsep
   Separates strings.

   Format

     #include  <string.h>

     char *strsep  (char **stringp, char *delim);
 

3  Function_Variants
   The strsep function has variants named _strsep32 and _strsep64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

stringp

   A pointer to a pointer to a character string.
 

delim

   A pointer to a string containing characters to be used as
   delimiters.
 

3  Description
   The strsep function locates in stringp, the first occurrence of
   any character in delim (or the terminating '\0' character) and
   replaces it with a '\0'. The location of the next character after
   the delimiter character (or NULL, if the end of the string is
   reached) is stored in the stringp argument. The original value of
   the stringp argument is returned.

   You can detect an "empty" field; one caused by two adjacent
   delimiter characters, by comparing the location referenced by
   the pointer returned in the stringp argument to '\0'.

   The stringp argument is initially NULL, strsep returns NULL.
 

3  Return_Values

   x                  The address of the string pointed to by
                      stringp.
   NULL               Indicates that stringp is NULL.
 

3  Example

     The following example uses strsep to parse a string, containing
     token delimited by white space, into an argument vector:

       char **ap, **argv[10], *inputstring;

       for (ap = argv; (*ap = strsep(&inputstring, " \t")) != NULL;)
            if (**ap != '\0')
                ++ap;
 

2  strspn
   Returns the length of the prefix of a string that consists
   entirely of characters from a set of characters.

   Format

     #include  <string.h>

     size_t strspn  (const char *str, const char *charset);
 

3  Arguments
 

str

   A pointer to a character string. If this string is a null string,
   0 is returned.
 

charset

   A pointer to a character string containing the characters for
   which the function will search.
 

3  Description
   The strspn function scans the characters in the string, stops
   when it encounters a character not found in charset, and returns
   the length of the string's initial segment formed by characters
   found in charset.
 

3  Return_Value

   x                  The length of the segment.
 

2  strstr
   Locates the first occurrence in the string pointed to by s1 of
   the sequence of characters in the string pointed to by s2.

   Format

     #include  <string.h>

     char *strstr  (const char *s1, const char *s2);
 

3  Function_Variants
   The strstr function has variants named _strstr32 and _strstr64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

s1, s2

   Pointers to character strings.
 

3  Return_Values

   Pointer            A pointer to the located string.
   NULL               Indicates that the string was not found.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <string.h>

       main()
       {
           static char lookin[]="that this is a test was at the end";

           putchar('\n');
           printf("String: %s\n", &lookin[0] );
           putchar('\n');
           printf("Addr: %s\n", &lookin[0] );
           printf("this: %s\n", strstr( &lookin[0] ,"this") );
           printf("that: %s\n", strstr( &lookin[0] , "that" ) );
           printf("NULL: %s\n", strstr( &lookin[0], "" ) );
           printf("was: %s\n", strstr( &lookin[0], "was" ) );
           printf("at: %s\n", strstr( &lookin[0], "at" ) );
           printf("the end: %s\n", strstr( &lookin[0], "the end") );
           putchar('\n');

           exit(0);
       }

   This example produces the following results:

   $ RUN STRSTR_EXAMPLE
   String: that this is a test was at the end
   Addr: that this is a test was at the end
   this: this is a test was at the end
   that: that this is a test was at the end
   NULL: that this is a test was at the end
   was: was at the end
   at: at this is a test was at the end
   the end: the end
   $
 

2  strtod
   Converts a given string to a double-precision number.

   Format

     #include  <stdlib.h>

     double strtod  (const char *nptr, char **endptr);
 

3  Function_Variants
   The strtod function has variants named _strtod32 and _strtod64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

nptr

   A pointer to the character string to be converted to a double-
   precision number.
 

endptr

   The address of an object where the function can store the address
   of the first unrecognized character that terminates the scan. If
   endptr is a NULL pointer, the address of the first unrecognized
   character is not retained.
 

3  Description
   The strtod function recognizes an optional sequence of white-
   space characters (as defined by isspace), then an optional plus
   or minus sign, then a sequence of digits optionally containing a
   radix character, then an optional letter (e or E) followed by an
   optionally signed integer. The first unrecognized character ends
   the conversion.

   The string is interpreted by the same rules used to interpret
   floating constants.

   The radix character is defined the program's current locale
   (category LC_NUMERIC).

   This function returns the converted value. For strtod, overflows
   are accounted for in the following manner:

   o  If the correct value causes an overflow, HUGE_VAL (with a plus
      or minus sign according to the sign of the value) is returned
      and errno is set to ERANGE.

   o  If the correct value causes an underflow, 0 is returned and
      errno is set to ERANGE.

   If the string starts with an unrecognized character, then the
   conversion is not performed, *endptr is set to nptr, a 0 value is
   returned, and errno is set to EINVAL.)
 

3  Return_Values

   x                  The converted string.
   0                  Indicates the conversion could not be
                      performed. errno is set to one of the
                      following:

                      o  EINVAL - No conversion could be performed.

                      o  ERANGE - The value would cause an
                         underflow.

                      o  ENOMEM - Not enough memory available for
                         internal conversion buffer.

   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
 

2  strtok
   Split strings into tokens.

   Format

     #include  <string.h>

     char *strtok  (char *s1, const char *s2);

     char *strtok_r  (char *s, const char *sep, char **lasts);
 

3  Function_Variants
   The strtok function has variants named _strtok32 and _strtok64
   for use with 32-bit and 64-bit pointer sizes, respectively.
   Likewise, the strtok_r function has variants named _strtok_r32
   and _strtok_r64.
 

3  Arguments
 

s1

   On the first call, a pointer to a string containing zero or more
   text tokens. On all subsequent calls for that string, a NULL
   pointer.
 

s2

   A pointer to a separator string consisting of one or more
   characters. The separator string may differ from call to call.
 

s

   A null-terminated string that is a sequence of zero or more text
   tokens separated by spans of one or more characters from the
   separator string sep.
 

sep

   A null-terminated string of separator characters. This separator
   string can be different from call to call.
 

lasts

   A pointer that points to a user-provided pointer to stored
   information needed for strtok_r to continue scanning the same
   string.
 

3  Description
   The strtok function locates text tokens in a given string. The
   text tokens are delimited by one or more characters from a
   separator string that you specify. The function keeps track of
   its position in the string between calls and, as successive calls
   are made, the function works through the string, identifying the
   text token following the one identified by the previous call.

   A token in s1 starts at the first character that is not a
   character in the separator string s2 and ends either at the end
   of the string or at (but not including) a separator character.

   The first call to the strtok function returns a pointer to the
   first character in the first token and writes a null character
   into s1 immediately following the returned token. Each subsequent
   call (with the value of the first argument remaining NULL)
   returns a pointer to a subsequent token in the string originally
   pointed to by s1. When no tokens remain in the string, the strtok
   function returns a NULL pointer. (This can occur on the first
   call to strtok if the string is empty or contains only separator
   characters.)

   Since strtok inserts null characters into s1 to delimit tokens,
   s1 cannot be a const object.

   The strtok_r function is the reentrant version of strtok. The
   function strtok_r considers the null-terminated string s as a
   sequence of zero or more text tokens separated by spans of one or
   more characters from the separator string sep. The lasts argument
   points to a user-provided pointer to stored information needed
   for strtok_r to continue scanning the same string.

   In the first call to strtok_r, s points to a null-terminated
   string, sep points to a null-terminated string of separator
   characters, and the value pointed to by lasts is ignored. The
   strtok_r function returns a pointer to the first character of
   the first token, writes a null character into s immediately
   following the returned token, and updates the pointer to which
   lasts points.

   In subsequent calls, s is a NULL pointer and lasts is unchanged
   from the previous call so that subsequent calls move through the
   string s, returning successive tokens until no tokens remain. The
   separator string sep can be different from call to call. When no
   token remains in s, a NULL pointer is returned.
 

3  Return_Values

   x                  A pointer to the first character of the parsed
                      token in the string.
   NULL               Indicates that there are no tokens remaining
                      in the string.
 

3  Examples

   1.#include <stdio.h>

     #include <string.h>

     main()
     {
         static char str[] = "...ab..cd,,ef.hi";

         printf("|%s|\n", strtok(str, "."));
         printf("|%s|\n", strtok(NULL, ","));
         printf("|%s|\n", strtok(NULL, ",."));
         printf("|%s|\n", strtok(NULL, ",."));
     }

     Running this example program produces the following results:

       $ RUN STRTOK_EXAMPLE1
       |ab|
       |.cd|
       |ef|
       |hi|
       $

   2.#include <stdio.h>

     #include <string.h>

     main()
     {
        char *ptr,
             string[30];

        /* The first character not in the string "-" is "A".  The   */
        /* token ends at "C.                                        */

         strcpy(string, "ABC");
         ptr = strtok(string, "-");
         printf("|%s|\n", ptr);

         /* Returns NULL because no characters not in separator      */
         /* string "-" were found (i.e.  only separator characters   */
         /* were found)                                              */

         strcpy(string, "-");
         ptr = strtok(string, "-");
         if (ptr == NULL)
             printf("ptr is NULL\n");

     }

     Running this example program produces the following results:

       $ RUN STRTOK_EXAMPLE2
       |abc|
       ptr is NULL
       $
 

2  strtol
   Converts strings of ASCII characters to the appropriate numeric
   values.

   Format

     #include  <stdlib.h>

     long int strtol  (const char *nptr, char **endptr, int base);
 

3  Function_Variants
   The strtol function has variants named _strtol32 and _strtol64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

nptr

   A pointer to the character string to be converted to a long.
 

endptr

   The address of an object where the function can store a pointer
   to the first unrecognized character encountered in the conversion
   process (that is, the character that follows the last character
   in the string being converted). If endptr is a NULL pointer, the
   address of the first unrecognized character is not retained.
 

base

   The value, 2 through 36, to use as the base for the conversion.
 

3  Description
   The strtol function recognizes strings in various formats,
   depending on the value of the base. This function ignores
   any leading white-space characters (as defined by isspace in
   <ctype.h>) in the given string. It recognizes an optional plus
   or minus sign, then a sequence of digits or letters that may
   represent an integer constant according to the value of the base.
   The first unrecognized character ends the conversion.

   Leading zeros after the optional sign are ignored, and 0x or 0X
   is ignored if the base is 16.

   If base is 0, the sequence of characters is interpreted by
   the same rules used to interpret an integer constant: after
   the optional sign, a leading 0 indicates octal conversion, a
   leading 0x or 0X indicates hexadecimal conversion, and any other
   combination of leading characters indicates decimal conversion.

   Truncation from long to int can take place after assignment or
   by an explicit cast (arithmetic exceptions not withstanding).
   The function call atol (str) is equivalent to strtol (str,
   (char**)NULL, 10).
 

3  Return_Values

   x                  The converted value.
   LONG_MAX or LONG_  Indicates that the converted value would cause
   MIN                an overflow.
   0                  Indicates that the string starts with an
                      unrecognized character or that the value for
                      base is invalid. If the string starts with
                      an unrecognized character, *endptr is set to
                      nptr.
 

2  strtoq,strtoll
   Convert strings of ASCII characters to the appropriate numeric
   values. strtoll is a synonym for strtoq.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdlib.h>

     __int64 strtoq  (const char *nptr, char **endptr, int base);

     __int64 strtoll  (const char *nptr, char **endptr, int base);
 

3  Function_Variants
   These functions have variants named _strtoq32, _strtoll32 and
   _strtoq64, _strtoll64 for use with 32-bit and 64-bit pointer
   sizes, respectively.
 

3  Arguments
 

nptr

   A pointer to the character string to be converted to an __int64.
 

endptr

   The address of an object where the function can store a pointer
   to the first unrecognized character encountered in the conversion
   process (that is, the character that follows the last character
   in the string being converted). If endptr is a NULL pointer, the
   address of the first unrecognized character is not retained.
 

base

   The value, 2 through 36, to use as the base for the conversion.
 

3  Description
   The strtoq and strtoll functions recognize strings in various
   formats, depending on the value of the base. Any leading white-
   space characters (as defined by isspace in <ctype.h>) in the
   given string are ignored. The functions recognize an optional
   plus or minus sign, then a sequence of digits or letters that may
   represent an integer constant according to the value of the base.
   The first unrecognized character ends the conversion.

   Leading zeros after the optional sign are ignored, and 0x or 0X
   is ignored if the base is 16.

   If base is 0, the sequence of characters is interpreted by
   the same rules used to interpret an integer constant: after
   the optional sign, a leading 0 indicates octal conversion, a
   leading 0x or 0X indicates hexadecimal conversion, and any other
   combination of leading characters indicates decimal conversion.

   The function call atoq (str) is equivalent to strtoq (str,
   (char**)NULL, 10).
 

3  Return_Values

   x                  The converted value.
   __INT64_MAX or     Indicates that the converted value would cause
   __INT64_MIN        an overflow.
   0                  Indicates that the string starts with an
                      unrecognized character or that the value for
                      base is invalid. If the string starts with
                      an unrecognized character, *endptr is set to
                      nptr.
 

2  strtoul
   Converts the initial portion of the string pointed to by nptr to
   an unsigned long integer.

   Format

     #include  <stdlib.h>

     unsigned long int strtoul  (const char *nptr, char **endptr, int base);         
 

3  Function_Variants
   The strtoul function has variants named _strtoul32 and _strtoul64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

nptr

   A pointer to the character string to be converted to an unsigned
   long.
 

endptr

   The address of an object where the function can store a pointer
   to a pointer to the first unrecognized character encountered in
   the conversion process (that is, the character that follows the
   last character in the string being converted). If endptr is a
   NULL pointer, the address of the first unrecognized character is
   not retained.
 

base

   The value, 2 through 36, to use as the base for the conversion.
   Leading zeros after the optional sign are ignored, and 0x or 0X
   is ignored if the base is 16.

   If the base is 0, the sequence of characters is interpreted by
   the same rules used to interpret an integer constant: after
   the optional sign, a leading 0 indicates octal conversion, a
   leading 0x or 0X indicates hexadecimal conversion, and any other
   combination of leading characters indicates decimal conversion.
 

3  Return_Values

   x                  The converted value.
   0                  Indicates that the string starts with an
                      unrecognized character or that the value for
                      base is invalid. If the string starts with
                      an unrecognized character, *endptr is set to
                      nptr.
   ULONG_MAX          Indicates that the converted value would cause
                      an overflow.
 

2  strtouq,strtoull
   Convert the initial portion of the string pointed to by nptr to
   an unsigned __int64 integer. strtoull is a synonym for strtouq.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdlib.h>

     unsigned __int64 strtouq  (const char *nptr, char **endptr, int base);

     unsigned __int64 strtoull  (const char *nptr, char **endptr, int base);
 

3  Function_Variants
   These functions have variants named _strtouq32, _strtoull32 and
   _strtouq64, _strtoull64 for use with 32-bit and 64-bit pointer
   sizes, respectively.
 

3  Arguments
 

nptr

   A pointer to the character string to be converted to an unsigned
   __int64.
 

endptr

   The address of an object where the function can store a pointer
   to a pointer to the first unrecognized character encountered in
   the conversion process (that is, the character that follows the
   last character in the string being converted). If endptr is a
   NULL pointer, the address of the first unrecognized character is
   not retained.
 

base

   The value, 2 through 36, to use as the base for the conversion.
   Leading zeros after the optional sign are ignored, and 0x or 0X
   is ignored if the base is 16.

   If the base is 0, the sequence of characters is interpreted by
   the same rules used to interpret an integer constant: after
   the optional sign, a leading 0 indicates octal conversion, a
   leading 0x or 0X indicates hexadecimal conversion, and any other
   combination of leading characters indicates decimal conversion.
 

3  Return_Values

   x                  The converted value.
   0                  Indicates that the string starts with an
                      unrecognized character or that the value for
                      base is invalid. If the string starts with
                      an unrecognized character, *endptr is set to
                      nptr.
   __UINT64_MAX       Indicates that the converted value would cause
                      an overflow.
 

2  strxfrm
   Changes a string such that the changed string can be passed to
   the strcmp function, and produce the same result as passing the
   unchanged string to the strcoll function.

   Format

     #include  <string.h>

     size_t strxfrm  (char *s1, const char *s2, size_t maxchar);
 

3  Arguments
 

s1, s2

   Pointers to character strings.
 

maxchar

   The maximum number of bytes (including the null terminator) to be
   stored in s1.
 

3  Description
   The strxfrm function transforms the string pointed to by s2,
   and stores the resulting string in the array pointed to by s1.
   No more than maxchar bytes, including the null terminator, are
   placed into the array pointed to by s1.

   If the value of maxchar is less than the required size to store
   the transformed string (including the terminating null), the
   contents of the array pointed to by s1 is indeterminate. In such
   a case, the function returns the size of the transformed string.

   If maxchar is 0, then s1 is allowed to be a NULL pointer, and the
   function returns the required size of the s1 array before making
   the transformation.

   The string comparison functions, strcoll and strcmp, can produce
   different results given the same two strings to compare. The
   reason for this is that strcmp does a straightforward comparison
   of the code point values of the characters in the strings,
   whereas strcoll uses the locale information to do the comparison.
   Depending on the locale, the strcoll comparison can be a
   multipass operation, which is slower than strcmp.

   The purpose of the strxfrm function is to transform strings in
   such a way that if you pass two transformed strings to the strcmp
   function, the result is the same as passing the two original
   strings to the strcoll function. The strxfrm function is useful
   in applications that need to do a large number of comparisons on
   the same strings using strcoll. In this case, it might be more
   efficient (depending on the locale) to transform the strings once
   using strxfrm, and then do comparisons using strcmp.
 

3  Return_Value

   x                  Length of the resulting string pointed to
                      by s1, not including the terminating null
                      character.

                      No return value is reserved for error
                      indication. However, the function can set
                      errno to EINVAL - The string pointed to by s2
                      contains characters outside the domain of the
                      collating sequence.
 

3  Example

       /* This program verifies that two transformed strings when      */
       /* passed through strxfrm and then compared, provide the same   */
       /* result as if passed through strcoll without any              */
       /* transformation.

       #include <string.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <locale.h>

       #define  BUFF_SIZE  256

       main()
       {
          char string1[BUFF_SIZE];
          char string2[BUFF_SIZE];
          int errno;
          int coll_result;
          int strcmp_result;
          size_t strxfrm_result1;
          size_t strxfrm_result2;

          /* setlocale to French locale */

          if (setlocale(LC_ALL, "fr_FR.ISO8859-1") == NULL) {
              perror("setlocale");
              exit(EXIT_FAILURE);
          }

          /* collate string 1 and string 2 and store the result */

          errno = 0;
          coll_result = strcoll("<a`>bcd", "abcz");
          if (errno) {
              perror("strcoll");
              exit(EXIT_FAILURE);
          }

          else {
              /* Transform the strings (using strxfrm) into string1   */
              /* and string2                                          */

              strxfrm_result1 = strxfrm(string1, "<a`>bcd", BUFF_SIZE);

              if (strxfrm_result1 == ((size_t) - 1)) {
                  perror("strxfrm");
                  exit(EXIT_FAILURE);
              }

              else if (strxfrm_result1 > BUFF_SIZE) {
                  perror("\n** String is too long **\n");
                  exit(EXIT_FAILURE);
              }

              else {
                  strxfrm_result2 = strxfrm(string2, "abcz", BUFF_SIZE);
                  if (strxfrm_result2 == ((size_t) - 1)) {
                      perror("strxfrm");
                      exit(EXIT_FAILURE);
                  }

                  else if (strxfrm_result2 > BUFF_SIZE) {
                      perror("\n** String is too long **\n");
                      exit(EXIT_FAILURE);
                  }

                  /* Compare the two transformed strings and verify   */
                  /* that the result is the same as the result from   */
                  /* strcoll on the original strings                  */
                  else {
                      strcmp_result = strcmp(string1, string2);
                      if (strcmp_result == 0 && (coll_result == 0)) {
                          printf("\nReturn value from strcoll() and "
                            "return value from strcmp() are both zero.");
                         printf("\nThe program was successful\n\n");
                      }

                      else if ((strcmp_result < 0) && (coll_result < 0)) {
                          printf("\nReturn value from strcoll() and "
                       "return value from strcmp() are less than zero.");
                          printf("\nThe program successful\n\n");
                      }

                      else if ((strcmp_result > 0) && (coll_result > 0)) {
                          printf("\nReturn value from strcoll() and "
                    "return value from strcmp() are greater than zero.");
                          printf("\nThe program was successful\n\n");
                      }

                      else {
                      printf("** Error **\n");
                      printf("\nReturn values are not of the same type");
                      }
                   }
               }
          }
       }

   Running the example program produces the following result:

   Return value from strcoll() and return value
                  from strcmp() are less than zero.
   The program was successful
 

2  subwin
   Creates a new subwindow with numlines lines and numcols columns
   starting at the coordinates (begin_y,begin_x) on the terminal
   screen.

   Format

     #include  <curses.h>

     WINDOW *subwin  (WINDOW *win, int numlines, int numcols, int
                     begin_y, int begin_x);
 

3  Arguments
 

win

   A pointer to the parent window.
 

numlines

   The number of lines in the subwindow. If numlines is 0, then
   the function sets that dimension to LINES - begin_y. To get a
   subwindow of dimensions LINES by COLS, use the following format:

   subwin (win, 0, 0, 0, 0)
 

numcols

   The number of columns in the subwindow. If numcols is 0, then
   the function sets that dimension to COLS - begin_x. To get a
   subwindow of dimensions LINES by COLS, use the following format:

   subwin (win, 0, 0, 0, 0)
 

begin_y

   A window coordinate at which the subwindow is to be created.
 

begin_x

   A window coordinate at which the subwindow is to be created.
 

3  Description
   When creating the subwindow, begin_y and begin_x are relative to
   the entire terminal screen. If either numlines or numcols is 0,
   then the subwin function sets that dimension to (LINES - begin_y)
   or (COLS - begin_x), respectively.

   The window pointed to by win must be large enough to contain the
   entire area of the subwindow. Any changes made to either window
   within the coordinates of the subwindow appear on both windows.
 

3  Return_Values

   window pointer     A pointer to an instance of the structure
                      window corresponding to the newly created
                      subwindow.
   ERR                Indicates an error.
 

2  swab
   Swaps bytes.

   Format

     #include  <unistd.h>

     void swab  (const void *src, void *dest, ssize_t nbytes);
 

3  Arguments
 

src

   A pointer to the location of the string to copy.
 

dest

   A pointer to where you want the results copied.
 

nbytes

   The number of bytes to copy. Make this argument an even value.
   When it is an odd value, the swab function uses nbytes -1
   instead.
 

3  Description
   The swab function copies the number of bytes specified by nbytes
   from the location pointed to by src to the array pointed to by
   dest. The function then exchanges adjacent bytes. If a copy takes
   place between objects that overlap, the result is undefined.
 

2  swprintf
   Writes output to an array of wide characters under control of the
   wide-character format string.

   Format

     #include  <wchar.h>

     int swprintf  (wchar_t *s, size_t n, const wchar_t          
                   *format, . . . );
 

3  Arguments
 

s

   A pointer to the resulting wide-character sequence.
 

n

   The maximum number of wide characters that can be written to
   an array pointed to by s, including a terminating null wide
   character.
 

format

   A pointer to a wide-character string containing the format
   specifications.
 

 . . .

   Optional expressions whose resultant types correspond to
   conversion specifications given in the format specification.

   If no conversion specifications are given, the output sources can
   be omitted. Otherwise, the function calls must have exactly as
   many output sources as there are conversion specifications, and
   the conversion specifications must match the types of the output
   sources.

   Conversion specifications are matched to output sources in left-
   to-right order. Excess output pointers, if any, are ignored.
 

3  Description
   The swprintf function is equivalent to the fwprintf function,
   except that the first argument specifies an array of wide
   characters instead of a stream.

   No more than n wide characters are written, including a
   terminating null wide character, which is always added (unless
   n is 0).

   See also fwprintf.
 

3  Return_Values

   x                  The number of wide characters written, not
                      counting the terminating null wide character.
   Negative value     Indicates an error. Either n or more wide
                      characters were requested to be written, or a
                      conversion error occurred, in which case errno
                      is set to EILSEQ.
 

2  swscanf
   Reads input from a wide-character string under control of the
   wide-character format string.

   Format

     #include  <wchar.h>

     int swscanf  (const wchar_t *s, const wchar_t *format, . . . );
 

3  Arguments
 

s

   A pointer to a wide-character string from which the input is to
   be obtained.
 

format

   A pointer to a wide-character string containing the format
   specifications.
 

 . . .

   Optional expressions whose results correspond to conversion
   specifications given in the format specification.

   If no conversion specifications are given, you can omit the input
   pointers. Otherwise, the function calls must have exactly as
   many input pointers as there are conversion specifications, and
   the conversion specifications must match the types of the input
   pointers.

   Conversion specifications are matched to input sources in left-
   to-right order. Excess input pointers, if any, are ignored.
 

3  Description
   The swscanf function is equivalent to the fwscanf function,
   except that the first argument specifies a wide-character string
   rather than a stream. Reaching the end of the wide-character
   string is the same as encountering EOF for the fwscanf function.

   See also fwscanf.
 

3  Return_Values

   x                  The number of input items assigned, sometimes
                      fewer than provided for, or even 0 in the
                      event of an early matching failure.
   EOF                Indicates an error. An input failure occurred
                      before any conversion.
 

2  symlink
   Creates a symbolic link containing the specified contents.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     int symlink  (const char *link_contents, const char *link_name);
 

3  Arguments
 

link_contents

   Contents of the symbolic link file, specified as a text string
   representing the pathname to which the symbolic link will point.
 

link_name

   The text string representing the name of the symbolic link file.
 

3  Description
   A symbolic link is a special kind of file that points to another
   file. It is a directory entry that associates a filename with a
   text string that is interpreted as a POSIX pathname when accessed
   by certain services. A symbolic link is implemented on OpenVMS
   systems as a file of organization SPECIAL and type SYMBOLIC_LINK.

   The symlink function creates a symbolic link (link_name)
   containing the specified contents (link_contents). No attempt
   is made at link creation time to interpret the symbolic link
   contents.

   See also readlink, unlink, realpath, lchown, and lstat.
 

3  Return_Values

   0                  Successful completion
   -1                 Indicates an error. errno is set to indicate
                      the error:

                      o  EACCES - Write permission is denied in the
                         directory where the symbolic link is being
                         created, or search permission is denied
                         for a component of the path prefix of link_
                         name.

                      o  EEXIST - The link_name argument names an
                         existing file or symbolic link.

                      o  ENAMETOOLONG - The length of the link_name
                         argument exceeds PATH_MAX, or a pathname
                         component is longer than NAME_MAX, or the
                         length of the link_contents argument is
                         longer than SYMLINK_MAX.

                      o  ENOSPC - The directory in which the entry
                         for the new symbolic link is being placed
                         cannot be extended because no space is
                         left on the file system containing the
                         directory, or the new symbolic link cannot
                         be created because no space is left on the
                         file system that would contain the link, or
                         the file system is out of file-allocation
                         resources.

                      o  Any errno value from creat, fsync, lstat,
                         or write.
 

2  sysconf
   Gets configurable system variables.

   Format

     #include  <unistd.h>

     long int sysconf  (int name);
 

3  Argument
 

name

   Specifies the system variable to be queried.
 

3  Description
   The sysconf function provides a method for determining the
   current value of a configurable system limit or whether optional
   features are supported.

   You supply a symbolic constant in the name argument, and sysconf
   returns a value for the corresponding system variable:

   o  The symbolic constants defined in the <unistd.h> header file.

   o  The system variables are defined in the <limits.h> and
      <unistd.h> header files.

   sysconf Argument and Return Values lists the system variables
   returned by the sysconf function, and the symbolic constants that
   you can supply as the name value.

   Table REF-10 sysconf Argument and Return Values

                     Symbolic
   System Variable   Constant for
   Returned          name           Meaning

   ISO POSIX-1

   ARG_MAX           _SC_ARG_MAX    The maximum length, in bytes,
                                    of the arguments for one of
                                    the exec functions, including
                                    environment data.
   CHILD_MAX         _SC_CHILD_     The maximum number of
                     MAX            simultaneous processes for each
                                    real user ID.
   CLK_TCK           _SC_CLK_TCK    The number of clock ticks per
                                    second. The value of CLK_TCK
                                    can be variable. Do not assume
                                    that CLK_TCK is a compile-time
                                    constant.
   NGROUPS_MAX       _SC_NGROUPS_   The maximum number of
                     MAX            simultaneous supplementary group
                                    IDs for each process.
   OPEN_MAX          _SC_OPEN_MAX   The maximum number of files that
                                    one process can have open at one
                                    time.
   STREAM_MAX        _SC_STREAM_    The number of streams that one
                     MAX            process can have open at one
                                    time.
   TZNAME_MAX        _SC_TZNAME_    The maximum number of bytes
                     MAX            supported for the name of a time
                                    zone (not the length of the TZ
                                    environmental variable).
   _POSIX_JOB_       _SC_JOB_       This variable has a value of
   CONTROL           CONTROL        1 if the system supports job
                                    control; otherwise, -1 is
                                    returned.
   _POSIX_SAVED_IDS  _SC_SAVED_     This variable has a value of 1
                     IDS            if each process has a saved set
                                    user ID and a saved set group
                                    ID; otherwise, -1 is returned.
   _POSIX_VERSION    _SC_VERSION    The date of approval of the
                                    most current version of the
                                    POSIX-1 standard that the system
                                    supports. The date is a 6-digit
                                    number, with the first 4 digits
                                    signifying the year and the last
                                    2 digits the month.

                                    If_POSIX_VERSION is not defined,
                                    -1 is returned.

                                    Different versions of the POSIX-
                                    1 standard are periodically
                                    approved by the IEEE Standards
                                    Board, and the date of approval
                                    is used to distinguish between
                                    different versions.


   ISO POSIX-2

   BC_BASE_MAX       _SC_BC_BASE_   The maximum value allowed for
                     MAX            the obase variable with the bc
                                    command.
   BC_DIM_MAX        _SC_BC_DIM_    The maximum number of elements
                     MAX            permitted in an array by the bc
                                    command.
   BC_SCALE_MAX      _SC_BC_        The maximum value allowed for
                     SCALE_MAX      the scale variable with the bc
                                    command.
   BC_STRING_MAX     _SC_BC_        The maximum length of string
                     STRING_MAX     constants accepted by the bc
                                    command.
   COLL_WEIGHTS_MAX  _SC_COLL_      The maximum number of weights
                     WEIGHTS_MAX    that can be assigned to an
                                    entry in the LC_COLLATE locale-
                                    dependent information in a
                                    locale definition file.
   EXPR_NEST_MAX     _SC_EXPR_      The maximum number of
                     NEST_MAX       expressions that you can nest
                                    within parentheses by the expr
                                    command.
   LINE_MAX          _SC_LINE_MAX   The maximum length, in bytes,
                                    of a command input line (either
                                    standard input or another file)
                                    when the utility is described
                                    as processing text files. The
                                    length includes room for the
                                    trailing new-line character.
   RE_DUP_MAX        _SC_RE_DUP_    The maximum number of repeated
                     MAX            occurrences of a regular
                                    expression permitted when using
                                    the interval notation arguments,
                                    such as the m and n arguments
                                    with the ed command.
   _POSIX2_CHAR_     _SC_2_CHAR_    This variable has a value of 1
   TERM              TERM           if the system supports at least
                                    one terminal type; otherwise, -1
                                    is returned.
   _POSIX2_C_BIND    _SC_2_C_BIND   This variable has a value of
                                    1 if the system supports the
                                    C language binding option;
                                    otherwise, -1 is returned.
   _POSIX2_C_DEV     _SC_2_C_DEV    This variable has a value of
                                    1 if the system supports the
                                    optional C Language Development
                                    Utilities from the ISO POSIX-
                                    2 standard; otherwise, -1 is
                                    returned.
   _POSIX2_C_        _SC_2_C_       Integer value indicating the
   VERSION           VERSION        version of the ISO POSIX-2
                                    standard (C language binding).
                                    It changes with each new version
                                    of the ISO POSIX-2 standard.
   _POSIX2_VERSION   _SC_2_         Integer value indicating the
                     VERSION        version of the ISO POSIX-2
                                    standard (Commands). It changes
                                    with each new version of the ISO
                                    POSIX-2 standard.
   _POSIX2_FORT_DEV  _SC_2_FORT_    The variable has a value of 1 if
                     DEV            the system supports the Fortran
                                    Development Utilities Option
                                    from the ISO POSIX-2 standard;
                                    otherwise, -1 is returned.
   _POSIX2_FORT_RUN  _SC_2_FORT_    The variable has a value of
                     RUN            1 if the system supports the
                                    Fortran Runtime Utilities Option
                                    from the ISO POSIX-2 standard;
                                    otherwise, -1 is returned.
   _POSIX2_          _SC_2_         The variable has a value of
   LOCALEDEF         LOCALEDEF      1 if the system supports the
                                    creation of new locales with the
                                    localedef command; otherwise, -1
                                    is returned.
   _POSIX2_SW_DEV    _SC_2_SW_DEV   The variable has a value of 1 if
                                    the system supports the Software
                                    Development Utilities Option
                                    from the ISO POSIX-2 standard;
                                    otherwise, -1 is returned.
   _POSIX2_UPE       _SC_2_UPE      The variable has a value of 1
                                    if the system supports the User
                                    Portability Utilities Option;
                                    otherwise, -1 is returned.


   POSIX 1003.1c-1995

   _POSIX_THREADS    _SC_THREADS    This variable has a value of 1
                                    if the system supports POSIX
                                    threads; otherwise, -1 is
                                    returned.
   _POSIX_THREAD_    _SC_THREAD_    This variable has a value of 1
   ATTR_STACKSIZE    ATTR_          if the system supports the POSIX
                     STACKSIZE      threads stack size attribute;
                                    otherwise, -1 is returned.
   _POSIX_THREAD_    _SC_THREAD_    The 1003.1c implementation
   PRIORITY_         PRIORITY_      supports the realtime scheduling
   SCHEDULING        SCHEDULING     functions.
   _POSIX_THREAD_    _SC_THREAD_    TRUE if the implementation
   SAFE_FUNCTIONS    SAFE_          supports the thread-safe ANSI
                     FUNCTIONS      C functions in POSIX 1003.1c.
   PTHREAD_          _SC_THREAD_    When a thread terminates,
   DESTRUCTOR_       DESTRUCTOR_    DECthreads iterates through
   ITERATIONS        ITERATIONS     all non-NULL thread-specific
                                    data values in the thread, and
                                    calls a registered destructor
                                    routine (if any) for each. It
                                    is possible for a destructor
                                    routine to create new values for
                                    one or more thread-specific data
                                    keys. In that case, DECthreads
                                    goes through the entire process
                                    again.

                                    _SC_THREAD_DESTRUCTOR_ITERATIONS
                                    is the maximum number of times
                                    the implementation loops before
                                    it terminates the thread even if
                                    there are still non-NULL values.
   PTHREAD_KEYS_MAX  _SC_THREAD_    The maximum number of thread-
                     KEYS_MAX       specific data keys that an
                                    application can create.
   PTHREAD_STACK_    _SC_THREAD_    The minimum allowed size of a
   MIN               STACK_MIN      stack for a new thread. Any
                                    lower value specified for the
                                    "stacksize" thread attribute is
                                    rounded up.
   UINT_MAX          _SC_THREAD_    The maximum number of threads
                     THREADS_MAX    an application is allowed to
                                    create. Since DECthreads does
                                    not enforce any fixed limit,
                                    this value is -1.



   X/Open

   _XOPEN_VERSION    _SC_XOPEN_     An integer indicating the
                     VERSION        most current version of the
                                    X/Open standard that the system
                                    supports.
   PASS_MAX          _SC_PASS_MAX   Maximum number of significant
                                    bytes in a password (not
                                    including terminating null).
   XOPEN_CRYPT       _SC_XOPEN_     This variable has a value of
                     CRYPT          1 if the system supports the
                                    X/Open Encryption Feature Group;
                                    otherwise, -1 is returned.
   XOPEN_ENH_I18N    _SC_XOPEN_     This variable has a value
                     ENH_I18N       of 1 if the system supports
                                    the X/Open enhanced
                                    Internationalization Feature
                                    Group; otherwise, -1 is
                                    returned.
   XOPEN_SHM         _SC_XOPEN_     This variable has a value
                     SHM            of 1 if the system supports
                                    the X/Open Shared Memory
                                    Feature Group; otherwise, -1
                                    is returned.


   X/Open Extended

   ATEXIT_MAX        _SC_ATEXIT_    The maximum number of functions
                     MAX            that you can register with
                                    atexit per process.
   PAGESIZE          _SC_PAGESIZE   Size, in bytes, of a page.
   PAGE_SIZE         _SC_PAGE_      Same as PAGESIZE. If either
                     SIZE           PAGESIZE or PAGE_SIZE is
                                    defined, the other is defined
                                    with the same value.
   IOV_MAX           _SC_IOV_MAX    Maximum number of iovec
                                    structures that one process
                                    has available for use with readv
                                    or writev.
   XOPEN_UNIX        _SC_XOPEN_     This variable has a value of
                     UNIX           1 if the system supports the
                                    X/Open CAE Specification, August
                                    1994, System Interfaces and
                                    Headers, Issue 4, Version 2,
                                    (ISBN: 1-85912-037-7, C435);
                                    otherwise, -1 is returned.



   Other

   N/A               _SC_CPU_       Returns information for
                     CHIP_TYPE      the processor type. See the
                                    description after this table.

   For the _SC_CPU_CHIP_TYPE symbolic constant:

   o  On Alpha servers, sysconf returns the architecture type (2),
      as given by the $GETSYI system service.

   o  Integrity processor information is stored in CPUID register
      3. This register contains a 64-bit integer divided into 1-byte
      fields indicating version information related to the processor
      implementation. The sysconf function returns the low-order
      longword with the following information:

      31     24 23    16 15    8 7     0
      ----------------------------------
      | family | model  | rev   |number|
      ----------------------------------

   These fields are described in the following table:

   Field  Bits   Description

   number 7:0    Index of the largest implemented CPUID register
                 (one less than the number of implemented CPUID
                 registers). This value will be at least 4.
   rev    15:8   Processor revision number. An 8-bit value that
                 represents the revision or stepping of this
                 processor implementation within the processor
                 model.
   model  23:16  Processor model number. A unique 8-bit value
                 representing the processor model within the
                 processor family.
   family 31:24  Processor family number. A unique 8-bit value
                 representing the processor family.
 

3  Return_Values

   x                  The current variable value on the system. The
                      value does not change during the lifetime of
                      the calling process.
   -1                 Indicates an error.

                      If the value of the name argument is invalid,
                      errno is set to indicate the error.

                      If the value of the name argument is
                      undefined, errno is unchanged.
 

2  system
   Passes a given string to the host environment to be executed by a
   command processor. This function is nonreentrant.

   Format

     #include  <stdlib.h>

     int system  (const char *string);
 

3  Argument
 

string

   A pointer to the string to be executed. If string is NULL, a
   nonzero value is returned. The string is a DCL command, not
   the name of an image. To execute an image, use one of the exec
   routines.
 

3  Description
   The system function spawns a subprocess and executes the command
   specified by string in that subprocess. The system function waits
   for the subprocess to complete before returning the subprocess
   status as the return value of the function.

   The subprocess is spawned within the system call by a call to
   vfork. Because of this, a call to system should not be made after
   a call to vfork and before the corresponding call to an exec
   function.

   For OpenVMS Version 7.0 and higher systems, if you include
   <stdlib.h> and compile with the _POSIX_EXIT feature-test macro
   set, then the system function returns the status as if it called
   waitpid to wait for the child. Therefore, use the WIFEXITED and
   WEXITSTATUS macros (described in the wait* routines) to retrieve
   the exit status in the range of 0 to 255.

   You set the _POSIX_EXIT feature-test macro by using /DEFINE=_
   POSIX_EXIT or #define _POSIX_EXIT at the top of your file, before
   any file inclusions.
 

3  Return_Value

   nonzero value      If string is NULL, a value of 1 is returned,
                      indicating that the system function is
                      supported. If string is not NULL, the value
                      is the subprocess OpenVMS return status.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <unistd.h>     /* write, close */
       #include <fcntl.h>      /* Creat */

       main()
       {
           int status,
               fd;

           /* Creat a file we are sure is there        */

           fd = creat("system.test", 0);
           write(fd, "this is an example of using system", 34);
           close(fd);

           if (system(NULL)) {
               status = system("DIR/NOHEAD/NOTRAIL/SIZE SYSTEM.TEST");
               printf("system status = %d\n", status);
           }
           else
               printf("system() not supported.\n");
       }

   Running this example program produces the following result:

   DISK3$:[JONES.CRTL.2059.SRC]SYSTEM.TEST;1
                              1
   system status = 1
 

2  tan
   Returns a double value that is the tangent of its radian
   argument.

   Format

     #include  <math.h>

     double tan  (double x);

     float tanf  (float x); (Integrity servers, Alpha)

     long double tanl  (long double x); (Integrity servers, Alpha)

     double tand  (double x); (Integrity servers, Alpha)

     float tandf  (float x); (Integrity servers, Alpha)

     long double tandl  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A radian expressed as a real number.
 

3  Description
   The tan functions compute the tangent of x, measured in radians.

   The tand functions compute the tangent of x, measured in degrees.
 

3  Return_Values

   x                  The tangent of the argument.
   HUGE_VAL           x is a singular point ( . . . -3pi/2, -pi/2,
                      pi/2 . . . ).
   NaN                x is NaN; errno is set to EDOM.
   0                  x is Infinity; errno is set to EDOM.
   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
   0                  Underflow occurred; errno is set to ERANGE.
 

2  tanh
   Returns the hyperbolic tangent of its argument.

   Format

     #include  <math.h>

     double tanh  (double x);

     float tanhf  (float x); (Integrity servers, Alpha)

     long double tanhl  (long double x); (Integrity servers, Alpha)
 

3  Argument
 

x

   A real number.
 

3  Description
   The tanh functions return the hyperbolic tangent their argument,
   calculated as (e**x - e**(-x))/(e**x + e**(-x)).
 

3  Return_Values

   n                  The hyperbolic tangent of the argument.
   HUGE_VAL           The argument is too large; errno is set to
                      ERANGE.
   NaN                x is NaN; errno is set to EDOM.
   0                  Underflow occurred; errno is set to ERANGE.
 

2  telldir
   Returns the current location associated with a specified
   directory stream. Performs operations on directories.

   Format

     #include  <dirent.h>

     long int telldir  (DIR *dir_pointer);
 

3  Argument
 

dir_pointer

   A pointer to the DIR structure of an open directory.
 

3  Description
   The telldir function returns the current location associated with
   the specified directory stream.
 

3  Return_Values

   x                  The current location.
   -1                 Indicates an error and is further specified in
                      the global errno.
 

2  tempnam
   Constructs the name for a temporary file.

   Format

     #include  <stdio.h>

     char *tempnam  (const char *directory, const char

                    *prefix, . . . ;)
 

3  Arguments
 

directory

   A pointer to the pathname of the directory where you want to
   create a file.
 

prefix

   A pointer to an initial character sequence of the filename. The
   prefix argument can be null, or it can point to a string of up
   to five characters used as the first characters of the temporary
   filename.
 

 . . .

   An optional argument that can be either 1 or 0. If you specify 1,
   tempnam returns the file specification in OpenVMS format. If you
   specify 0, tempnam returns the file specification in UNIX style
   format.
 

3  Description
   The tempnam function generates filenames for temporary files. It
   allows you to control the choice of a directory.

   If the directory argument is null or points to a string that is
   not a pathname for an appropriate directory, the pathname defined
   as P_tmpdir in the <stdio.h> header file is used. For programs
   running under a detached process, the directory argument cannot
   be null.

   You can bypass the selection of a pathname by providing the
   TMPDIR environment variable in the user environment. The value
   of the TMPDIR variable is a pathname for the desired temporary
   file directory.

   Use the prefix argument to specify a prefix of up to five
   characters for the temporary filename.

   The tempnam function returns a pointer to the generated pathname,
   suitable for use in a subsequent call to the free function.

   See also free.

                                  NOTE

      In contrast to tmpnam, tempnam does not have to generate
      a different filename on each call. tempnam generates a new
      filename only if the file with the specified name exists. If
      you need a unique filename on each call, use tmpnam instead
      of tempnam.
 

3  Return_Values

   x                  A pointer to the generated pathname, suitable
                      for use in a subsequent call to the free
                      function.
   NULL               An error occurred; errno is set to indicate
                      the error.
 

2  tgamma
   Returns the gamma function of its argument.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double tgamma  (double x);

     float tgammaf  (float x);

     long double tgammal  (long double x);
 

3  Argument
 

x

   A real value.
 

3  Description
   The tgamma functions compute the gamma function of x.
 

3  Return_Values

   n                  Upon success, the gamma function of x.
   -1                 If x is negative. errno is set to EDOM.
   HUGE_VAL           Overflow occurred, or x is 0. errno is set to
                      ERANGE.
   NaN                If x is NaN or -Inf. errno is set to EDOM.
   x                  If x is +Inf.
 

2  time
   Returns the time (expressed as Universal Coordinated Time)
   elapsed since 00:00:00, January 1, 1970, in seconds.

   Format

     #include  <time.h>

     time_t time  (time_t *time_location);
 

3  Function_Variants
   Compiling with the _DECC_V4_SOURCE and _VMS_V6_SOURCE feature-
   test macros defined enables a local-time-based entry point to the
   time function that is equivalent to the behavior before OpenVMS
   Version 7.0.
 

3  Argument
 

time_location

   Either NULL or a pointer to the place where the returned time is
   also stored. The time_t type is defined in the <time.h> header
   file as follows:

   typedef unsigned long int time_t;
 

3  Return_Values

   x                  The time elapsed past the Epoch.
   (time_t)(-1)       Indicates an error. If the value of
                      SYS$TIMEZONE_DIFFERENTIAL logical is wrong,
                      the function will fail with errno set to
                      EINVAL.
 

2  times
   Passes back the accumulated times of the current process and its
   terminated child processes.

   Format

     #include  <times.h>

     clock_t times  (struct tms *buffer); (OpenVMS V7.0 and higher)

     void times  (tbuffer_t *buffer); (pre OpenVMS V7.0)
 

3  Argument
 

buffer

   A pointer to the terminal buffer.
 

3  Description
   For both process and children times, the structure breaks down
   the time by user and system time. Since the OpenVMS system does
   not differentiate between system and user time, all system times
   are returned as 0. Accumulated CPU times are returned in 10-
   millisecond units.

   Only the accumulated times for child processes running a C main
   program or a program that calls VAXC$CRTL_INIT or DECC$CRTL_INIT
   are included.

   On OpenVMS Version 7.0 and higher systems, the times function
   returns the elapsed real time in clock ticks since an arbitrary
   reference time in the past (for example, system startup time).
   This reference time does not change from one times function call
   to another. The return value can overflow the possible range of
   type clock_t values. When times fails, it returns a value of -1.
   The Compaq C RTL uses system-boot time as its reference time.
 

3  Return_Values

   x                  The elapsed real time in clock ticks since
                      system-boot time.
   (clock_t)(-1)      Indicates an error.
 

2  tmpfile
   Creates a temporary file that is opened for update.

   Format

     #include  <stdio.h>

     FILE *tmpfile  (void);
 

3  Description
   The file exists only for the duration of the process, or until
   the file is closed and is preserved across calls to vfork.
 

3  Return_Values

   x                  The address of a file pointer (defined in the
                      <stdio.h> header file).
   NULL               Indicates an error.
 

2  tmpnam
   Generates filenames that can be safely used for a temporary file.

   Format

     #include  <stdio.h>

     char *tmpnam  (char *name);
 

3  Function_Variants
   The tmpnam function has variants named _tmpnam32 and _tmpnam64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Argument
 

name

   A character string containing a name to use in place of file-name
   arguments in functions or macros. Successive calls to tmpnam with
   a null argument cause the function to overwrite the current name.
 

3  Return_Value

   x                  If the name argument is the NULL pointer
                      value NULL, tmpnam returns the address of
                      an internal storage area. If name is not NULL,
                      then it is considered the address of an area
                      of length L_tmpnam (defined in the <stdio.h>
                      header file). In this case, tmpnam returns the
                      name argument as the result.
 

2  toascii
   Converts its argument, an 8-bit ASCII character, to a 7-bit ASCII
   character.

   Format

     #include  <ctype.h>

     int toascii  (char character);
 

3  Argument
 

character

   An object of type char.
 

3  Return_Value

   x                  A 7-bit ASCII character.
 

2  tolower
   Converts a character to lowercase.

   Format

     #include  <ctype.h>

     int tolower  (int character);
 

3  Argument
 

character

   An object of type int representable as an unsigned char or the
   value of EOF. For any other value, the behavior is undefined.
 

3  Description
   If the argument represents an uppercase letter, and there is
   a corresponding lowercase letter, as defined by character
   type information in the program locale category LC_CTYPE, the
   corresponding lowercase letter is returned.

   If the argument is not an uppercase character, it is returned
   unchanged.
 

3  Return_Value

   x                  The lowercase letter corresponding to the
                      argument. Or, the unchanged argument, if it is
                      not an uppercase character.
 

2  _tolower
   Converts an uppercase character to lowercase.

   Format

     #include  <ctype.h>

     int _tolower  (int character);
 

3  Argument
 

character

   This argument must be an uppercase letter.
 

3  Description
   The _tolower macro is equivalent to the tolower function except
   that its argument must be an uppercase letter (not lowercase, not
   EOF).

   As of OpenVMS Version 8.3 and to comply with the C99 ANSI
   standard and X/Open Specification, the _tolower macro by default
   does not evaluate its parameter more than once. It simply calls
   the tolower function. This avoids side effects (such as i++
   or function calls) where the user can tell how many times an
   expression is evaluated.

   To keep the older, optimized _tolower macro behavior, compile
   with /DEFINE=_FAST_TOUPPER. Then, as in previous releases, _
   tolower optimizes the call to avoid the overhead of a runtime
   call. The parameters are checked to determine how to calculate
   the result, thereby creating unwanted side effects. Therefore,
   when compiling with /DEFINE=_FAST_TOUPPER, do not use the _
   tolower macro with arguments that contain side-effect operations.
   For instance, the following example will not return the expected
   result:

   d = _tolower (C++);
 

3  Return_Value

   x                  The lowercase letter corresponding to the
                      argument.
 

2  touchwin
   Places the most recently edited version of the specified window
   on the terminal screen.

   Format

     #include  <curses.h>

     int touchwin  (WINDOW *win);
 

3  Argument
 

win

   A pointer to the window.
 

3  Description
   The touchwin function is normally used only to refresh
   overlapping windows.
 

3  Return_Values

   OK                 Indicates success.
   ERR                Indicates an error.
 

2  toupper
   Converts a character to uppercase.

   Format

     #include  <ctype.h>

     int toupper  (int character);
 

3  Argument
 

character

   An object of type int representable as an unsigned char or the
   value of EOF. For any other value, the behavior is undefined.
 

3  Description
   If the argument represents a lowercase letter, and there is
   a corresponding uppercase letter, as defined by character
   type information in the program locale category LC_CTYPE, the
   corresponding uppercase letter is returned.

   If the argument is not a lowercase character, it is returned
   unchanged.
 

3  Return_Value

   x                  The uppercase letter corresponding to the
                      argument. Or, the unchanged argument, if the
                      argument is not a lowercase character.
 

2  _toupper
   Converts a lowercase character to uppercase.

   Format

     #include  <ctype.h>

     int _toupper  (int character);
 

3  Argument
 

character

   This argument must be a lowercase letter.
 

3  Description
   The _toupper macro is equivalent to the toupper function except
   that its argument must be a lowercase letter (not uppercase, not
   EOF).

   As of OpenVMS Version 8.3 and to comply with the C99 ANSI
   standard and X/Open Specification, the _toupper macro by default
   does not evaluate parameters more than once. It simply calls
   the toupper function. This avoids side effects (such as i++
   or function calls) where the user can tell how many times an
   expression is evaluated.

   To keep the older, optimized _toupper macro behavior, compile
   with /DEFINE=_FAST_TOUPPER. Then, as in previous releases, _
   toupper optimizes the call to avoid the overhead of a runtime
   call. The parameters are checked to determine how to calculate
   the result, thereby creating unwanted side effects. So when
   compiling with /DEFINE=_FAST_TOUPPER, do not use the _toupper
   macro with arguments that contain side-effect operations. For
   instance, the following example will not return the expected
   result:

   d = _toupper (c++);
 

3  Return_Value

   x                  The uppercase letter corresponding to the
                      argument.
 

2  towctrans
   Maps one wide character to another according to a specified
   mapping descriptor.

   Format

     #include  <wctype.h>

     wint_t towctrans  (wint_t wc, wctrans_t desc);
 

3  Arguments
 

wc

   The wide character that you want to map.
 

desc

   Description of the mapping obtained through a call to the wctrans
   function.
 

3  Description
   The towctrans function maps the wide character specified in wc,
   using the mapping described by desc.

   The current setting of the LC_CTYPE category must be the same as
   during the call to the wctrans function that returned the value
   of desc.
 

3  Return_Value

   x                  The mapped value of the wc wide character,
                      if this character exists in the mapping
                      described by desc. Otherwise, the value of
                      wc is returned.
 

2  towlower
   Converts the argument, a wide-character code, to lowercase.
   If the argument is not an uppercase character, it is returned
   unchanged.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int towlower  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t representable as a valid wide character
   in the current locale, or the value of WEOF. For any other value,
   the behavior is undefined.
 

3  Description
   If the argument is an uppercase wide character, the corresponding
   lowercase wide character (as defined in the LC_CTYPE category of
   the locale) is returned, if it exists. If it does not exist, the
   function returns the input argument unchanged.
 

2  towupper
   Converts the argument, a wide character, to uppercase. If the
   argument is not a lowercase character, it is returned unchanged.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     int towupper  (wint_t wc);
 

3  Argument
 

wc

   An object of type wint_t representable as a valid wide character
   in the current locale, or the value of WEOF. For any other value,
   the behavior is undefined.
 

3  Description
   If the argument is a lowercase wide character, the corresponding
   uppercase wide character (as defined in the LC_CTYPE category of
   the locale) is returned, if it exists. If it does not exist, the
   function returns the input argument unchanged.
 

2  trunc
   Truncates the argument to an integral value.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double trunc  (double x);

     float truncf  (float x,);

     long double truncl  (long double x);
 

3  Argument
 

x

   A floating-point number.
 

3  Return_Value

   n                  The truncated, integral value of the argument.
 

2  truncate
   Changes file length to a specified length, in bytes.

   Format

     #include  <unistd.h>

     int truncate  (const char *path, off_t length);
 

3  Arguments
 

path

   The name of a file that is to be truncated. This argument must
   point to a pathname that names a regular file for which the
   calling process has write permission.
 

length

   The new length of the file, in bytes. The off_t type of length
   is either a 64-bit or 32-bit integer. The 64-bit interface allows
   for file sizes greater than 2 GB, and can be selected at compile
   time by defining the _LARGEFILE feature-test macro as follows:

   CC/DEFINE=_LARGEFILE
 

3  Description
   The truncate function changes the length of a file to the size,
   in bytes, specified by the length argument.

   If the new length is less than the previous length, the function
   removes all data beyond length bytes from the specified file. All
   file data between the new End-of-File and the previous End-of-
   File is discarded.

   For stream files, if the new length is greater than the previous
   length, new file data between the previous End-of-File and the
   new End-of-File is added, consisting of all zeros. (For record
   files, it is not possible to extend the file in this manner.)
 

3  Return_Values

   0                  Indicates success.
   -1                 An error occurred; errno is set to indicate
                      the error.
 

2  ttyname
   Find the pathname of a terminal.

   Format

     #include  <unixio.h> (Compatibility)

     char *ttyname  (void); (Compatibility)

     #include  <unistd.h> (OpenVMS V7.3-2 and higher)

     char *ttyname  (int filedes); (OpenVMS V7.3-2 and higher)

     int ttyname_r  (int filedes, char name, size_t

                    namesize); (OpenVMS V7.3-2 and higher),

                    (Integrity servers, Alpha)
 

3  Arguments
 

filedes

   An open file descriptor.
 

name

   Pointer to a buffer in which the terminal name is stored.
 

namesize

   The length of the buffer pointed to by the name argument.
 

3  Description
   The implementation of the ttyname function that takes no
   argument is provided only for backward compatibility. This
   legacy implementation returns a pointer to the null-terminated
   name of the terminal device associated with file descriptor 0,
   the default input device (stdin). A value of 0 is returned if
   SYS$INPUT is not a TTY device.

   The ttyname_r function and the implementation of ttyname that
   takes a filedes argument are UNIX standard compliant and are
   available with only OpenVMS Version 7.3-2 and higher.

   The standard compliant ttyname function returns a pointer to a
   string containing a null-terminated pathname of the terminal
   associated with file descriptor filedes. The return value might
   point to static data whose content is overwritten by each call.
   The ttyname interface need not be reentrant.

   The ttyname_r function returns a pointer to store the null-
   terminated pathname of the terminal associated with the file
   descriptor filedes in the character array referenced by name. The
   array is namesize characters long and should have space for the
   name and the terminating null character. The maximum length of
   the terminal name is TTY_NAME_MAX.

   If successful, ttyname returns a pointer to a string. Otherwise,
   a NULL pointer is returned and errno is set to indicate the
   error.

   If successful, ttyname_r stores the terminal name as a null-
   terminated string in the buffer pointed to by name and returns 0.
   Otherwise, an error number is returned to indicate the error.
 

3  Return_Values

   x                  Upon successful completion, ttyname returns a
                      pointer to a null-terminated string.
   NULL               Upon failure, ttyname returns a NULL pointer
                      and sets errno to indicate the failure:

                      o  EBADF - The fildes argument is not a valid
                         file descriptor.

                      o  ENOTTY - The fildes argument does not refer
                         to a terminal device.

   0                  Upon successful completion, ttyname_r returns
                      0.
   n                  Upon failure, ttyname_r sets errno to indicate
                      the failure, and returns the same errno code:

                      o  EBADF - The fildes argument is not a valid
                         file descriptor.

                      o  ENOTTY - The fildes argument does not refer
                         to a TTY device.

                      o  ERANGE - The value of namesize is smaller
                         than the length of the string to be
                         returned including the terminating null
                         character.

   0                  For the legacy ttyname, indicates that
                      SYS$INPUT is not a TTY device.
 

2  tzset
   Sets and accesses time-zone conversion.

   Format

     #include  <time.h>

     void tzset  (void);

     extern  char *tzname[];

     extern  long int timezone;

     extern  int daylight;
 

3  Description
   The tzset function initializes time-conversion information
   used by the ctime, localtime, mktime, strftime, and wcsftime
   functions.

   The tzset function sets the following external variables:

   o  tzname is set as follows, where "std" is a 3-byte name for
      the standard time zone, and "dst" is a 3-byte name for the
      Daylight Savings Time zone:

      tzname[0] = "std"
      tzname[1] = "dst"

   o  daylight is set to 0 if Daylight Savings Time should never be
      applied to the time zone. Otherwise, daylight is set to 1.

   o  timezone is set to the difference between UTC and local
      standard time.

   The environment variable TZ specifies how tzset initializes time
   conversion information:

   o  If TZ is absent from the environment, the implementation-
      dependent time-zone information is used, as follows:

         The best available approximation to local wall-clock time
         is used, as defined by the SYS$LOCALTIME system logical,
         which points to a tzfile format file that describes default
         time-zone rules.
         This system logical is set during the installation
         of OpenVMS Version 7.0 or higher to define a
         time-zone file based off the root directory
         SYS$COMMON:[SYS$ZONEINFO.SYSTEM].

   o  If TZ appears in the environment but its value is a null
      string, Coordinated Universal Time (UTC) is used (without
      leap-second correction).

   o  If TZ appears in the environment and its value is not a null
      string, the value has one of three formats, as described in
      Time-Zone Initialization Rules.

   Table REF-11 Time-Zone Initialization Rules

   TZ Format    Meaning

   :            UTC is used.
   :pathname    The characters following the colon specify the
                pathname of a tzfile format file from which to
                read the time-conversion information. A pathname
                beginning with a slash (/)  represents an absolute
                pathname; otherwise, the pathname is relative to
                the system time-conversion information directory
                specified by SYS$TZDIR, which by default is
                SYS$COMMON:[SYS$ZONEINFO.SYSTEM].
   stdoffset[dstThefset]e is first used as the pathname of a file
                (as described for the :pathname format) from which
   [,rule]]     to read the time-conversion information.

                If that file cannot be read, the value is then
                interpreted as a direct specification of the time-
                conversion information, as follows:
                std and dst-Three or more characters that are the
                designation for the time zone:

                o  std-Standard time zone. Required.

                o  dst-Daylight Savings Time zone. Optional. If dst
                   is omitted, Daylight Savings Time does not apply.

                Uppercase and lowercase letters are explicitly
                allowed. Any characters are allowed, except the
                following:

                o  digits

                o  leading colon (:)

                o  comma (,)

                o  minus (-)

                o  plus (+)

                o  ASCII null character

                offset-The value added to the local time to arrive
                at UTC. The offset has the following format:

                hh[:mm[:ss]]

                In this format:

                o  hh (hours) is a one-or two-digit value of 0-24.

                o  mm (minutes) is a value of 0-59. (optional)

                o  ss (seconds) is a value of 0-59. (optional)

                The offset following std is required. If no offset
                follows dst, summer time is assumed, one hour ahead
                of standard time. You can use one or more digits;
                the value is always interpreted as a decimal number.

                If the time zone is preceded by a minus sign (-),
                the time zone is East of Greenwich; otherwise, it
                is West, which can also be indicated by a preceding
                plus sign (+).
                rule-Indicates when to change to and return from
                summer time. The rule has the form:

                start[/time], end[/time]

                where:

                o  start is the date when the change from standard
                   time to summer time occurs.

                o  end is the date for returning from summer time to
                   standard time.

                If start and end are omitted, the default is the
                US Daylight Savings Time start and end dates.
                The format for start and end must be one of the
                following:

                o  Jn-The Julian day n (1 < n < 365). Leap days are
                   not counted. That is, in all years, including
                   leap years, February 28 is day 59 and March 1 is
                   day 60. You cannot explicitly refer to February
                   29.

                o  n-The zero based Julian day (0 < n < 365). Leap
                   days are counted, making it possible to refer to
                   February 29.

                o  Mm.n.d-The nth d day of month m, where:

                      0 < n < 5
                      0 < d < 6
                      1 < m < 12

                   When n is 5, it refers to the last d day of month
                   m. Sunday is day 0.

                time-The time when, in current time, the change to
                or return from summer time occurs. The time argument
                has the same format as offset, except that you
                cannot use a leading minus (-)  or plus (+) sign.
                If time is not specified, the default is 02:00:00.

                If no rule is present in the TZ specification, the
                rules used are those specified by the tzfile format
                file defined by the SYS$POSIXRULES system logical
                in the system time-conversion information directory,
                with the standard and summer time offsets from UTC
                replaced by those specified by the offset values in
                TZ.

                If TZ does not specify a tzfile format file and
                cannot be interpreted as a direct specification, UTC
                is used.

                                  NOTE


      The UTC-based time functions, introduced in OpenVMS Version
      7.0, had degraded performance compared with the non-UTC-
      based time functions.

      OpenVMS Version 7.1 added a cache for time-zone files to
      improve performance. The size of the cache is determined
      by the logical name DECC$TZ_CACHE_SIZE. To accommodate most
      countries changing the time twice per year, the default
      cache size is large enough to hold two time-zone files.

   See also ctime, localtime, mktime, strftime, and wcsftime.
 

3  Sample_TZ_Specification

       EST5EDT4,M4.1.0,M10.5.0

     This sample TZ specification describes the rule defined in 1987
     for the Eastern time zone in the US:

     o  EST (Eastern Standard Time) is the designation for standard
        time, which is 5 hours behind UTC.

     o  EDT (Eastern Daylight Time) is the designation for summer
        time, which is 4 hours behind UTC. EDT starts on the first
        Sunday in April and ends on the last Sunday in October.

     Because time was not specified in either case, the changes
     occur at the default time, which is 2:00 A.M. The start and
     end dates did not need to be specified, because they are the
     defaults.
 

2  ualarm
   Sets or changes the timeout of interval timers.

   Format

     #include  <unistd.h>

     useconds_t ualarm  (useconds_t mseconds, useconds_t interval);
 

3  Arguments
 

mseconds

   Specifies a number of real-time microseconds.
 

interval

   Specifies the interval for repeating the timer.
 

3  Description
   The ualarm function causes the SIGALRM signal to be generated for
   the calling process after the number of real-time microseconds
   specified by useconds has elapsed. When the interval argument is
   nonzero, repeated timeout notification occurs with a period in
   microseconds specified by interval. If the notification signal
   SIGALRM is not intercepted or is ignored, the calling process is
   terminated.

   If you call a combination of ualarm and setitimer functions, and
   the AST status is disabled, the return value is invalid.

   If you call a combination of ualarm and setitimer functions, and
   the AST status is enabled, the return value is valid.

   This is because you cannot invoke an AST handler to clear the
   previous value of the timer when ASTs are disabled or invoked
   from a handler that was invoked at AST level.

                                  NOTE

      Interactions between ualarm and either alarm, or sleep are
      unspecified.

   See also setitimer.
 

3  Return_Values

   n                  The number of microseconds remaining from the
                      previous ualarm or setitimer call.
   0                  No timeouts are pending or ualarm not
                      previously called.
   -1                 Indicates an error.
 

2  umask
   Creates a file protection mask that is used when a new file is
   created, and returns the previous mask value.

   Format

     #include  <stat.h>

     mode_t umask  (mode_t mode_complement);
 

3  Argument
 

mode_complement

   Shows which bits to turn off when a new file is created. See the
   description of chmod to determine what the bits represent.
 

3  Description
   Initially, the file protection mask is set from the current
   process's default file protection. This is done when the C main
   program starts up or when DECC$CRTL_INIT (or VAXC$CRTL_INIT)
   is called. You can change this for all files created by your
   program by calling umask or you can use chmod to change the file
   protection on individual files. The file protection of a file
   created by open or creat is the bitwise AND of the open and creat
   mode argument with the complement of the value passed to umask on
   the previous call.

                                  NOTE

      The way to create files with OpenVMS RMS default protections
      using the UNIX system-call functions umask, mkdir, creat,
      and open is to call mkdir, creat, and open with a file-
      protection mode argument of 0777 in a program that never
      specifically calls umask. These default protections include
      correctly establishing protections based on ACLs, previous
      versions of files, and so on.

      In programs that do vfork/exec calls, the new process image
      inherits whether umask has ever been called or not from
      the calling process image. The umask setting and whether
      the umask function has ever been called are both inherited
      attributes.
 

3  Return_Value

   x                  The old mask value.
 

2  uname
   Gets system identification information.

   Format

     #include  <utsname.h>

     int uname  (struct utsname *name);
 

3  Argument
 

name

   The current system identifier.
 

3  Description
   The uname function stores null-terminated strings of information
   identifying the current system into the structure referenced by
   the name argument.

   The utsname structure is defined in the <utsname.h> header file
   and contains the following members:

   sysname        Name of the operating system implementation
   nodename       Network name of this machine
   release        Release level of the operating system
   version        Version level of the operating system
   machine        Machine hardware platform
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error; errno or vaxc$errno is set
                      as appropriate.
 

2  ungetc
   Pushes a character back into the input stream and leaves the
   stream positioned before the character.

   Format

     #include  <stdio.h>

     int ungetc  (int character, FILE *file_ptr);
 

3  Arguments
 

character

   A value of type int.
 

file_ptr

   A file pointer.
 

3  Description
   When using the ungetc function, the character is pushed back onto
   the file indicated by file_ptr.

   One push-back is guaranteed, even if there has been no previous
   activity on the file. The fseek function erases all memory of
   pushed-back characters. The pushed-back character is not written
   to the underlying file. If the character to be pushed back is
   EOF, the operation fails, the input stream is left unchanged, and
   EOF is returned.

   See also fseek and getc.
 

3  Return_Values

   x                  The push-back character.
   EOF                Indicates it cannot push the character back.
 

2  ungetwc
   Pushes a wide character back into the input stream.

   Format

     #include  <wchar.h>

     wint_t ungetwc  (wint_t wc, FILE *file_ptr);
 

3  Arguments
 

wc

   A value of type wint_t.
 

file_ptr

   A file pointer.
 

3  Description
   When using the ungetwc function, the wide character is pushed
   back onto the file indicated by file_ptr.

   One push-back is guaranteed, even if there has been no previous
   activity on the file. If a file positioning function (such as
   fseek) is called before the pushed back character is read, the
   bytes representing the pushed back character are lost.

   If the character to be pushed back is WEOF, the operation fails,
   the input stream is left unchanged, and WEOF is returned.

   See also getwc.
 

3  Return_Values

   x                  The push-back character.
   WEOF               Indicates that the function cannot push the
                      character back. errno is set to one of the
                      following:

                      o  EBADF - The file descriptor is not valid.

                      o  EALREADY - Operation is already in progress
                         on the same file.

                      o  EILSEQ - Invalid wide-character code
                         detected.
 

2  unlink
   Deletes the specified symbolic link from the system.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <unistd.h>

     int unlink  (const char *link_name);
 

3  Arguments
 

link_name

   The name of the symbolic link to be deleted.
 

3  Description
   The unlink function deletes the specified symbolic link (link_
   name) from the system. The contents of the symbolic link are not
   examined, and no action is performed on the file specified in the
   contents. For other files, the unlink function behaves the same
   as the C RTL remove function.

   See also symlink, readlink, realpath, lchown, and lstat.
 

3  Return_Values

   0                  Successful completion.
   -1                 Indicates an error. The named file (link_name)
                      is unchanged, and errno is set to any errno
                      value from remove.
 

2  unordered
   Returns the value 1 (TRUE) if either or both of the arguments is
   a NaN. Otherwise, it returns the value 0 (FALSE).

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double unordered  (double x, double y);

     float unorderedf  (float x, float y);

     long double unorderedl  (long double x, long double y);
 

3  Arguments
 

x

   A real number.
 

y

   A real number.
 

3  Return_Values

   1                  Either or both of the arguments is a NaN.
   0                  Neither argument is a NaN.
 

2  unsetenv
   Deletes all instances of the environment variable name from the
   environment list.

   Format

     #include  <stdlib.h>

     void unsetenv  (const char *name);
 

3  Argument
 

name

   The environment variable to delete from the environment list.
 

3  Description
   The unsetenv function deletes all instances of the variable name
   pointed to by the name argument from the environment list.
 

2  usleep
   Suspends execution for an interval.

   Format

     #include  <unistd.h>

     int usleep  (unsigned int mseconds);
 

3  Argument
 

mseconds

   The number of microseconds to suspend execution for.
 

3  Description
   The usleep function suspends the current process from execution
   for the number of microseconds specified by the mseconds
   argument. This argument must be less than 1,000,000. However,
   if its value is 0, then the call has no effect.

   Be aware that usleep time specifications are rounded up
   approximately to the next millisecond because that is the finest
   time interval granularity possible on OpenVMS systems.

   There is one real-time interval timer for each process. The
   usleep function does not interfere with a previous setting of
   this timer. If the process set this timer before calling usleep
   and if the time specified by mseconds equals or exceeds the
   interval timer's prior setting, then the process is awakened
   shortly before the timer was set to expire.
 

3  Return_Values

   0                  Indicates success.
   -1                 Indicates an error occurred; errno is set to
                      EINVAL.
 

2  utime
   Sets file access and modification times.

   Format

     #include  <utime.h>

     int utime  (const char *path, const struct utimbuf *times);
 

3  Arguments
 

path

   A pointer to a file.
 

times

   A NULL pointer or a pointer to a utimbuf structure.
 

3  Description
   The utime function sets the access and modification times of the
   filenamed by the path argument. The file must be openable for
   write-access to use this function.

   If times is a NULL pointer, the access and modification times of
   the file are set to the current time. To use utime in this way,
   the effective user ID of the process must match the owner of the
   file, or the process must have write permission to the file or
   have appropriate privileges.

   If times is not a NULL pointer, it is interpreted as a pointer
   to a utimbuf structure, and the access and modification times
   are set to the values in the specified structure. Only a process
   with an effective user ID equal to the user ID of the file or a
   process with appropriate privileges can use utime this way.

   The utimbuf structure is defined by the <utime.h> header. The
   times in the utimbuf structure are measured in seconds since the
   Epoch.

   Upon successful completion, utime marks the time of the last file
   status change, st_ctime, to be updated. See the <stat.h> header
   file.

                    NOTE (Integrity servers, Alpha)

      On OpenVMS Alpha and Integrity server systems, the stat,
      fstat, utime, and utimes functions have been enhanced to
      take advantage of the new file-system support for POSIX
      compliant file timestamps.

      This support is available only on ODS-5 devices on OpenVMS
      Alpha systems beginning with a version of OpenVMS Alpha
      after Version 7.3.

      Before this change, stat and fstat set the values of the st_
      ctime, st_mtime, and st_atime fields based on the following
      file attributes:

         st_ctime - ATR$C_CREDATE (file creation time)
         st_mtime - ATR$C_REVDATE (file revision time)
         st_atime - was always set to st_mtime because no support
         for file access time was available

      Also, for the file-modification time, utime and utimes were
      modifying the ATR$C_REVDATE file attribute, and ignoring the
      file-access-time argument.

      After the change, for a file on an ODS-5 device, the stat
      and fstat functions set the values of the st_ctime, st_
      mtime, and st_atime fields based on the following new file
      attributes:

         st_ctime - ATR$C_ATTDATE (last attribute modification
         time)
         st_mtime - ATR$C_MODDATE (last data modification time)
         st_atime - ATR$C_ACCDATE (last access time)

      If ATR$C_ACCDATE is 0, as on an ODS-2 device, the stat and
      fstat functions set st_atime to st_mtime.

      For the file-modification time, the utime and utimes
      functions modify both the ATR$C_REVDATE and ATR$C_MODDATE
      file attributes. For the file-access time, these functions
      modify the ATR$C_ACCDATE file attribute. Setting the ATR$C_
      MODDATE and ATR$C_ACCDATE file attributes on an ODS-2 device
      has no effect.

      For compatibility, the old behavior of stat, fstat, utime,
      and utimes remains the default, regardless of the kind of
      device.

      The new behavior must be explicitly enabled by defining the
      DECC$EFS_FILE_TIMESTAMPS logical name to "ENABLE" before
      invoking the application. Setting this logical does not
      affect the behavior of stat, fstat, utime, and utimes for
      files on an ODS-2 device.
 

3  Return_Values

   0                  Successful execution.
   -1                 Indicates an error. The function sets errno to
                      one of the following values:

                      The utime function will fail if:

                      o  EACCES - Search permission is denied by
                         a component of the path prefix; or the
                         times argument is a NULL pointer and the
                         effective user ID of the process does
                         not match the owner of the file and write
                         access is denied.

                      o  ELOOP - Too many symbolic links were
                         encountered in resolving path.

                      o  ENAMETOOLONG - The length of the path
                         argument exceeds PATH_MAX, a pathname
                         component is longer than NAME_MAX, or a
                         pathname resolution of a symbolic link
                         produced an intermediate result whose
                         length exceeds PATH_MAX.

                      o  ENOENT - path does not name an existing
                         file, or path is an empty string.


                      o  ENOTDIR - A component of the path prefix is
                         not a directory.

                      o  EPERM - times is not a NULL pointer and
                         the calling process's effective user ID has
                         write-access to the file but does not match
                         the owner of the file, and the calling
                         process does not have the appropriate
                         privileges.

                      o  EROFS - The file system containing the file
                         is read-only.
 

2  utimes
   Sets file access and modification times.

   Format

     #include  <time.h>

     int utimes  (const char *path, const struct timeval times[2]);
 

3  Arguments
 

path

   A pointer to a file.
 

times

   an array of timeval structures. The first array member represents
   the date and time of last access, and the second member
   represents the date and time of last modification. The times
   in the timeval structure are measured in seconds and microseconds
   since the Epoch, although rounding toward the nearest second may
   occur.
 

3  Description
   The utimes function sets the access and modification times of the
   file pointed to by the path argument to the value of the times
   argument. The utimes function allows time specifications accurate
   to the microsecond.

   If the times argument is a NULL pointer, the access and
   modification times of the file are set to the current time. The
   effective user ID of the process must be the same as the owner
   of the file, or must have write access to the file or appropriate
   privileges to use this call in this manner.

   Upon completion, utimes marks the time of the last file status
   change, st_ctime, for update.

                    NOTE (Integrity servers, Alpha)

      On OpenVMS Alpha and Integrity server systems, the stat,
      fstat, utime, and utimes functions have been enhanced to
      take advantage of the new file-system support for POSIX
      compliant file timestamps.

      This support is available only on ODS-5 devices on OpenVMS
      Alpha systems beginning with a version of OpenVMS Alpha
      after Version 7.3.

      Before this change, the stat and fstat functions were
      setting the values of the st_ctime, st_mtime, and st_atime
      fields based on the following file attributes:

         st_ctime - ATR$C_CREDATE (file creation time)
         st_mtime - ATR$C_REVDATE (file revision time)
         st_atime - was always set to st_mtime because no support
         for file access time was available

      Also, for the file-modification time, utime and utimes were
      modifying the ATR$C_REVDATE file attribute, and ignoring the
      file-access-time argument.

      After the change, for a file on an ODS-5 device, the stat
      and fstat functions set the values of the st_ctime, st_
      mtime, and st_atime fields based on the following new file
      attributes:

         st_ctime - ATR$C_ATTDATE (last attribute modification
         time)
         st_mtime - ATR$C_MODDATE (last data modification time)
         st_atime - ATR$C_ACCDATE (last access time)

      If ATR$C_ACCDATE is 0, as on an ODS-2 device, the stat and
      fstat functions set st_atime to st_mtime.

      For the file-modification time, the utime and utimes
      functions modify both the ATR$C_REVDATE and ATR$C_MODDATE
      file attributes. For the file-access time, these functions
      modify the ATR$C_ACCDATE file attribute. Setting the ATR$C_
      MODDATE and ATR$C_ACCDATE file attributes on an ODS-2 device
      has no effect.

      For compatibility, the old behavior of stat, fstat, utime,
      and utimes remains the default, regardless of the kind of
      device.

      The new behavior must be explicitly enabled by defining the
      DECC$EFS_FILE_TIMESTAMPS logical name to "ENABLE" before
      invoking the application. Setting this logical does not
      affect the behavior of stat, fstat, utime, and utimes for
      files on an ODS-2 device.
 

3  Return_Values

   0                  Successful execution.
   -1                 Indicates an error. The file times do not
                      change and the function sets errno to one of
                      the following values:

                      The utimes function will fail if:

                      o  EACCES - Search permission is denied by
                         a component of the path prefix; or the
                         times argument is a NULL pointer and the
                         effective user ID of the process does
                         not match the owner of the file and write
                         access is denied.

                      o  ELOOP - Too many symbolic links were
                         encountered in resolving path.

                      o  ENAMETOOLONG - The length of the path
                         argument exceeds PATH_MAX, a pathname
                         component is longer than NAME_MAX, or a
                         pathname resolution of a symbolic link
                         produced an intermediate result whose
                         length exceeds PATH_MAX.

                      o  ENOENT - A component of path does not
                         name an existing file, or path is an empty
                         string.


                      o  ENOTDIR - A component of the path prefix is
                         not a directory.

                      o  EPERM -The times argument is not a NULL
                         pointer and the calling process's effective
                         user ID has write-access to the file but
                         does not match the owner of the file and
                         the calling process does not have the
                         appropriate privileges.

                      o  EROFS - The file system containing the file
                         is read-only.
 

2  VAXC$CRTL_INIT
   Allows you to call the Compaq C RTL from other languages or to
   use the Compaq C RTL when your main function is not in C. It
   initializes the run-time environment and establishes both an exit
   and condition handler. VAXC$CRTL_INIT is a synonym for DECC$CRTL_
   INIT. Either name invokes the same routine.

   Format

     #include  <signal.h>

     void VAXC$CRTL_INIT();
 

3  Description
   The following example shows a Pascal program that calls the
   Compaq C RTL using the VAXC$CRTL_INIT function:

   On OpenVMS Alpha systems:

   $ PASCAL EXAMPLE
   $ LINK EXAMPLE,SYS$LIBRARY:VAXCRTL/LIB
   $ TY EXAMPLE.PAS
   PROGRAM TESTC(input, output);
   PROCEDURE VAXC$CRTL_INIT; extern;
   BEGIN
      VAXC$CRTL_INIT;
   END
   $

   A shareable image need only call this function if it contains
   an Compaq C function for signal handling, environment variables,
   I/O, exit handling, a default file protection mask, or if it is a
   child process that should inherit context.

   Although many of the initialization activities are performed
   only once, DECC$CRTL_INIT can safely be called multiple times. On
   OpenVMS VAX systems, DECC$CRTL_INIT establishes the Compaq C RTL
   internal OpenVMS exception handler in the frame of the routine
   that calls DECC$CRTL_INIT each time DECC$CRTL_INIT is called.

   At least one frame in the current call stack must have that
   handler established for OpenVMS exceptions to get mapped to UNIX
   signals.
 

2  VAXC$ESTABLISH
   Used for establishing an OpenVMS exception handler for a
   particular routine. This function establishes a special Compaq C
   RTL exception handler in the routine that called it. This special
   handler catches all RTL-related exceptions that occur in later
   routines, and passes on all other exceptions to your handler.

   Format

     #include  <signal.h>

     void VAXC$ESTABLISH  (unsigned int (*exception_handler)(void
                          *sigarr, void *mecharr));
 

3  Arguments
 

exception_handler

   The name of the function that you want to establish as an OpenVMS
   exception handler. You pass a pointer to this function as the
   parameter to VAXC$ESTABLISH.
 

sigarr

   A pointer to the signal array.
 

mecharr

   A pointer to the mechanism array.
 

3  Description
   VAXC$ESTABLISH must be used in place of LIB$ESTABLISH when
   programs use the Compaq C RTL routines setjmp or longjmp. See
   setjmp and longjmp, or sigsetjmp and siglongjmp.

   You can only invoke the VAXC$ESTABLISH function from an Compaq C
   for OpenVMS function, because it relies on the allocation of data
   space on the run-time stack by the Compaq C compiler. Calling
   the OpenVMS system library routine LIB$ESTABLISH directly from an
   Compaq C function results in undefined behavior from the setjmp
   and longjmp functions.

   To cause an OpenVMS exception to generate a UNIX style signal,
   user exception handlers must return SS$_RESIGNAL upon receiving
   any exception that they do not want to handle. Returning SS$_
   NORMAL prevents the generation of a UNIX style signal. UNIX
   signals are generated as if by an exception handler in the
   stack frame of the main C program. Not all OpenVMS exceptions
   correspond to UNIX signals. See the "Error and Signal Handling"
   chapter of the HP C RTL Reference Manual. for more information on
   the interaction of OpenVMS exceptions and UNIX style signals.

   Calling VAXC$ESTABLISH with an argument of NULL cancels an
   existing handler in that routine.

                                 NOTES

      On OpenVMS Alpha systems, VAXC$ESTABLISH is implemented as a
      compiler built-in function, not as an Compaq C RTL function.
      (Alpha only)
 

2  va_arg
   Returns the next item in the argument list.

   Format

     #include  <stdarg.h> (ANSI C)

     #include  <varargs.h> (DEC C Extension)

     type va_arg  (va_list ap, type);
 

3  Arguments
 

ap

   A variable list containing the next argument to be obtained.
 

type

   A data type that is used to determine the size of the next item
   in the list. An argument list can contain items of varying sizes,
   but the calling routine must determine what type of argument is
   expected since it cannot be determined at run time.
 

3  Description
   The va_arg function interprets the object at the address
   specified by the list incrementor according to type. If there
   is no corresponding argument, the behavior is undefined.

   When using va_arg to write portable applications, include the
   <stdarg.h> header file (defined by the ANSI C standard), not the
   <varargs.h> header file, and use va_arg only in conjunction with
   other functions and macros defined in <stdarg.h>.

   For an example of argument-list processing using the <stdarg.h>
   functions and definitions, see the "Character, String, and
   Argument-List Functions" chapter of the HP C RTL Reference
   Manual.
 

2  va_count
   Returns the number of quadwords (Alpha only) in the argument
   list.

   Format

     #include  <stdarg.h> (ANSI C)

     #include  <varargs.h> (DEC C Extension)

     void va_count  (int count);
 

3  Argument
 

count

   An integer variable name in which the number of quadwords
   (Alpha only) is returned.
 

3  Description
   The va_count macro places the number of quadwords (Alpha only) in
   the argument list into count. The value returned in count is the
   number of quadwords (Alpha only) in the function argument block
   not counting the count field itself.

   If the argument list contains items whose storage requirements
   are a quadword (Alpha only) of memory or less, the number in
   the count argument is also the number of arguments. However, if
   the argument list contains items that are longer than a quadword
   (Alpha only), count must be interpreted to obtain the number of
   arguments. Because a double is 8 bytes, it occupies one argument-
   list position on OpenVMS Alpha and Integrity server systems.

   The va_count macro is specific to Compaq C for OpenVMS Systems
   and is not portable.
 

2  va_end
   Finishes the <varargs.h> or <stdarg.h> session.

   Format

     #include  <stdarg.h> (ANSI C)

     #include  <varargs.h> (DEC C Extension)

     void va_end  (va_list ap);
 

3  Argument
 

ap

   The object used to traverse the argument list length. You must
   declare and use the argument ap as shown in this format section.
 

3  Description
   You can execute multiple traversals of the argument list, each
   delimited by va_start . . . va_end. The va_end function sets ap
   equal to NULL.

   When using this function to write portable applications, include
   the <stdarg.h> header file (defined by the ANSI C standard), not
   the <varargs.h> header file, and use va_end only in conjunction
   with other routines defined in <stdarg.h>.

   For an example of argument-list processing using the <stdarg.h>
   functions and definitions, see the "Character, String, and
   Argument-List Functions" chapter of the HP C RTL Reference
   Manual.
 

2  va_start[_1]
   Used for initializing a variable to the beginning of the argument
   list.

   Format

     #include  <varargs.h> (DEC C Extension)

     void va_start  (va_list ap);

     void va_start_1  (va_list ap, int offset);
 

3  Arguments
 

ap

   An object pointer. You must declare and use the argument ap as
   shown in the format section.
 

offset

   The number of bytes by which ap is to be incremented so that
   it points to a subsequent argument within the list (that is,
   not to the start of the argument list). Using a nonzero offset
   can initialize ap to the address of the first of the optional
   arguments that follow a number of fixed arguments.
 

3  Description
   The va_start macro initializes the variable ap to the beginning
   of the argument list.

   The va_start_1 macro initializes ap to the address of an argument
   that is preceded by a known number of defined arguments. The
   printf function is an example of a Compaq C RTL function
   that contains a variable-length argument list offset from the
   beginning of the entire argument list. The variable-length
   argument list is offset by the address of the formatting string.

   When determining the value of the offset argument used in va_
   start_1, the implications of the OpenVMS calling standard must be
   considered.

   On OpenVMS Alpha and Integrity server systems, each argument item
   is a quadword.

                                  NOTE

      When accessing argument lists, especially those passed to a
      subroutine (written in C) by a program written in another
      programming language, consider the implications of the
      OpenVMS calling standard. For more information about the
      OpenVMS calling standard, see the Compaq C User's Guide for
      OpenVMS Systems or the HP OpenVMS Calling Standard.

   The preceding version of va_start and va_start_1 is specific to
   the Compaq C RTL, and is not portable.

   The following syntax describes the va_start macro in the
   <stdarg.h> header file, as defined in the ANSI C standard:

   Format

     #include  <stdarg.h> (ANSI C)

     void va_start  (va_list ap, parmN);
 

3  Arguments
 

ap

   An object pointer. You must declare and use the argument ap as
   shown in the format section.
 

parmN

   The name of the last of the known fixed arguments.
 

3  Description
   The pointer ap is initialized to point to the first of the
   optional arguments that follow parmN in the argument list.

   Always use this version of va_start in conjunction with functions
   that are declared and defined with function prototypes. Also use
   this version of va_start to write portable programs.

   For an example of argument-list processing using the <stdarg.h>
   functions and definitions, see the "Character, String, and
   Argument-List Functions" chapter of the HP C RTL Reference
   Manual.
 

2  vfork
   Creates an independent child process. This function is
   nonreentrant.

   Format

     #include  <unistd.h>

     int vfork  (void); (_DECC_V4_SOURCE)

     pid_t vfork  (void); (not _DECC_V4_SOURCE)
 

3  Description
   The vfork function provided by Compaq C for OpenVMS
   Systems differs from the fork function provided by other C
   implementations. The vfork and fork Functions shows the two major
   differences.

   Table REF-12 The vfork and fork Functions

   The vfork Function    The fork Function

   Used with the exec    Can be used without an exec function for
   functions.            asynchronous processing.
   Creates an            Creates an exact duplicate of the parent
   independent child     process that branches at the point where
   process that shares   vfork is called, as if the parent and the
   some of               child are the same process at different
   the parent's          stages of execution.
   characteristics.

   The vfork function provides the setup necessary for a subsequent
   call to an exec function. Although no process is created by
   vfork, it performs the following steps:

   o  It saves the return address (the address of the vfork call)
      to be used later as the return address for the call to an exec
      function.

   o  It saves the current context.

   o  It returns the integer 0 the first time it is called (before
      the call to an exec function is made). After the corresponding
      exec function call is made, the exec function returns control
      to the parent process, at the point of the vfork call, and
      it returns the process ID of the child as the return value.
      Unless the exec function fails, control appears to return
      twice from vfork even though one call was made to vfork and
      one call was made to the exec function.

   The behavior of the vfork function is similar to the behavior
   of the setjmp function. Both vfork and setjmp establish a return
   address for later use, both return the integer 0 when they are
   first called to set up this address, and both pass back the
   second return value as though it were returned by them rather
   than by their corresponding exec or longjmp function calls.

   However, unlike setjmp, with vfork, all local automatic
   variables, even those with volatile-qualified type, can have
   indeterminate values if they are modified between the call to
   vfork and the corresponding call to an exec routine.
 

3  Return_Values

   0                  Indicates successful creation of the context.
   nonzero            Indicates the process ID (PID) of the child
                      process.
   -1                 Indicates an error - failure to create the
                      child process.
 

2  vfprintf
   Prints formatted output based on an argument list.

   Format

     #include  <stdio.h>

     int vfprintf  (FILE *file_ptr, const char *format, va_list ap);
 

3  Arguments
 

file_ptr

   A pointer to the file to which the output is directed.
 

format

   A pointer to a string containing the format specification. For
   more information about format and conversion specifications and
   their corresponding arguments, see the "Understanding Input and
   Output" chapter of the HP C RTL Reference Manual.
 

ap

   A list of expressions whose resultant types correspond to the
   conversion specifications given in the format specifications.
 

3  Description
   See also vprintf and vsprintf.
 

3  Return_Values

   x                  The number of bytes written.
   Negative value     Indicates an output error. The function sets
                      errno. For a list of possible errno values
                      set, see fprintf.
 

2  vfscanf
   Reads formatted input based on an argument list.

   Format

     #include  <stdio.h>

     int vfscanf  (FILE *file_ptr, const char *format, va_list ap);
 

3  Arguments
 

file_ptr

   A pointer to the file that provides input text.
 

format

   A pointer to a string containing the format specification.
 

ap

   A list of expressions whose resultant types correspond to the
   conversion specifications given in the format specifications.
 

3  Description
   The vfscanf function is the same as the fscanf function except
   that instead of being called with a variable number of arguments,
   it is called with an argument list that has been initialized by
   va_start (and possibly subsequent va_arg calls).

   If no conversion specifications are given, you can omit the input
   pointers. Otherwise, the function calls must have exactly as
   many input pointers as there are conversion specifications, and
   the conversion specifications must match the types of the input
   pointers.

   Conversion specifications are matched to input sources in left-
   to-right order. Excess input pointers, if any, are ignored.

   For more information about format and conversion specifications
   and their corresponding arguments, see the "Understanding Input
   and Output" chapter of the HP C RTL Reference Manual.

   This function returns the number of successfully matched and
   assigned input items.

   See also vscanf and vsscanf.
 

3  Return_Values

   n                  The number of successfully matched and
                      assigned input items.
   EOF                Indicates that the end-of-file was encountered
                      or a read error occurred. If a read error
                      occurs, the function sets errno to one of the
                      following:

                      o  EILSEQ - Invalid character detected.

                      o  EINVAL - Insufficient arguments.

                      o  ENOMEM - Not enough memory available for
                         conversion.

                      o  ERANGE - Floating-point calculations
                         overflow.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This can indicate that conversion to a
                         numeric value failed due to overflow.

                      The function can also set errno to the
                      following as a result of errors returned from
                      the I/O subsystem:

                      o  EBADF - The file descriptor is not valid.

                      o  EIO - I/O error.

                      o  ENXIO - Device does not exist.

                      o  EPIPE - Broken pipe.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This indicates that an I/O error occurred
                         for which there is no equivalent C error
                         code.
 

2  vfwprintf
   Writes output to the stream under control of the wide-character
   format string.

   Format

     #include  <wchar.h>

     int vfwprintf  (FILE *stream, const wchar_t *format, va_list

                    ap);
 

3  Arguments
 

stream

   A file pointer.
 

format

   A pointer to a wide-character string containing the format
   specifications.
 

ap

   A variable list of the items needed for output.
 

3  Description
   The vfwprintf function is equivalent to the fwprintf function,
   with the variable argument list replaced by the ap argument.
   Initialize ap with the va_start macro (and possibly with
   subsequent va_arg calls) from <stdarg.h>.

   If the stream pointed to by stream has no orientation, vfwprintf
   makes the stream wide-oriented.

   See also fwprintf.
 

3  Return_Values

   n                  The number of wide characters written.
   Negative value     Indicates an error. The function sets errno to
                      one of the following:

                      o  EILSEQ - Invalid character detected.

                      o  EINVAL - Insufficient arguments.

                      o  ENOMEM - Not enough memory available for
                         conversion.

                      o  ERANGE - Floating-point calculations
                         overflow.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This might indicate that conversion to a
                         numeric value failed because of overflow.

                      The function can also set errno to the
                      following as a result of errors returned from
                      the I/O subsystem:

                      o  EBADF - The file descriptor is not valid.

                      o  EIO - I/O error.

                      o  ENOSPC - No free space on the device
                         containing the file.

                      o  ENXIO - Device does not exist.

                      o  EPIPE - Broken pipe.

                      o  ESPIPE - Illegal seek in a file opened for
                         append.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This indicates that an I/O error occurred
                         for which there is no equivalent C error
                         code.
 

3  Examples

     The following example shows the use of the vfwprintf function
     in a general error reporting routine:

        #include <stdarg.h>
        #include <stdio.h>
        #include <wchar.h>

        void error(char *function_name, wchar_t *format,  . . . );
        {
           va_list args;

           va_start(args, format);
           /* print out name of function causing error */
           fwprintf(stderr, L"ERROR in %s: ", function_name);
           /* print out remainder of message */
           vfwprintf(stderr, format, args);
           va_end(args);
        }
 

2  vfwscanf
   Reads input from the stream under control of a wide-character
   format string.

   Format

     #include  <wchar.h>

     int vfwscanf  (FILE *stream, const wchar_t *format, va_list

                   ap);
 

3  Arguments
 

stream

   A file pointer.
 

format

   A pointer to a wide-character string containing the format
   specifications.
 

ap

   A list of expressions whose resultant types correspond to the
   conversion specifications given in the format specifications.
 

3  Description
   The vfwscanf function is equivalent to the fwscanf function,
   except that instead of being called with a variable number of
   arguments, it is called with an argument list (ap) that has been
   initialized by va_start (and possibly with subsequent va_arg
   calls).

   If the stream pointed to by stream has no orientation, vfwscanf
   makes the stream wide-oriented.

   For more information about format and conversion specifications
   and their corresponding arguments, see the "Understanding Input
   and Output" chapter of the HP C RTL Reference Manual.
 

3  Return_Values

   n                  The number of successfully matched and
                      assigned wide-character input items.
   EOF                Indicates that a read error occurred before
                      any conversion. The function sets errno. For a
                      list of the values set by this function, see
                      vfscanf.
 

2  vprintf
   Prints formatted output based on an argument list.

   This function is the same as the printf function except that
   instead of being called with a variable number of arguments, it
   is called with an argument list that has been initialized by the
   va_start macro (and possibly with subsequent va_arg calls) from
   <stdarg.h>.

   Format

     #include  <stdio.h>

     int vprintf  (const char *format, va_list ap);
 

3  Arguments
 

format

   A pointer to the string containing the format specification.
 

ap

   A variable list of the items needed for output.
 

3  Description
   See the vfprintf and vsprintf functions.
 

3  Return_Values

   x                  The number of bytes written.
   Negative value     Indicates an output error. The function sets
                      errno. For a list of possible errno values
                      set, see fprintf.
 

2  vscanf
   Reads formatted input based on an argument list.

   Format

     #include  <stdio.h>

     int vscanf  (const char *format, va_list ap);
 

3  Arguments
 

format

   A pointer to the string containing the format specification.
 

ap

   A list of expressions whose resultant types correspond to the
   conversion specifications given in the format specifications.
 

3  Description
   The vscanf function is the same as the scanf function except that
   instead of being called with a variable number of arguments, it
   is called with an argument list (ap) that has been initialized by
   the va_start macro (and possibly with subsequent va_arg calls).

   For more information about format and conversion specifications
   and their corresponding arguments, see the "Understanding Input
   and Output" chapter of the HP C RTL Reference Manual.

   See also scanf, vfscanf, and vsscanf.
 

3  Return_Values

   n                  The number of successfully matched and
                      assigned input items.
   EOF                Indicates that a read error occurred before
                      any conversion. The function sets errno. For a
                      list of the values set by this function, see
                      vfscanf.
 

2  vsnprintf
   Prints formatted output based on an argument list.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <stdio.h>

     int vsnprintf  (char *str, size_t n, const char *format,    
                    va_list ap);
 

3  Arguments
 

str

   A pointer to a string that will receive the formatted output.
 

format

   A pointer to a character string that contains the format
   specification.
 

ap

   A list of expressions whose resultant types correspond to the
   conversion specifications given in the format specifications.
 

3  Description
   The vsnprintf function is the same as the snprintf function, but
   instead of being called with a variable number of arguments, it
   is called with an argument list that has been initialized by va_
   start (and possibly with subsequent va_arg calls).

   This function does not invoke the va_end macro. Because the
   function invokes the va_arg macro, the value of ap after the
   return is unspecified.

   Applications using vsnprintf should call va_end(ap) afterwards to
   clean up.
 

3  Return_Values

   x                  The number of bytes (excluding the terminating
                      null byte) that would be written to str if n
                      is sufficiently large.
   Negative value     Indicates an output error occurred. The
                      function sets errno. For a list of possible
                      errno values set, see fprintf.
 

2  vsprintf
   Prints formatted output based on an argument list.

   This function is the same as the sprintf function except that
   instead of being called with a variable number of arguments, it
   is called with an argument list that has been initialized by va_
   start (and possibly with subsequent va_arg calls).

   Format

     #include  <stdio.h>

     int vsprintf  (char *str, const char *format, va_list ap);
 

3  Arguments
 

str

   A pointer to a string that will receive the formatted output.
   This string is assumed to be large enough to hold the output.
 

format

   A pointer to a character string that contains the format
   specification.
 

ap

   A list of expressions whose resultant types correspond to the
   conversion specifications given in the format specifications.
 

3  Return_Value

   x                  The number of bytes written.
   Negative value     Indicates an output error occurred. The
                      function sets errno. For a list of possible
                      errno values set, see fprintf.
 

2  vsscanf
   Reads formatted input based on an argument list.

   Format

     #include  <stdio.h>

     int vsscanf  (char *str, const char *format, va_list ap);
 

3  Arguments
 

str

   The address of the character string that provides the input text
   to sscanf.
 

format

   A pointer to a character string that contains the format
   specification.
 

ap

   A list of expressions whose resultant types correspond to the
   conversion specifications given in the format specifications.
 

3  Description
   The vsscanf function is the same as the sscanf function except
   that instead of being called with a variable number of arguments,
   it is called with an argument list that has been initialized by
   va_start (and possibly with subsequent va_arg calls).

   The vsscanf function is also equivalent to the vfscanf function,
   except that the first argument specifies a wide-character string
   rather than a stream. Reaching the end of the wide-character
   string is the same as encountering EOF for the vfscanf function.

   For more information about format and conversion specifications
   and their corresponding arguments, see the "Understanding Input
   and Output" chapter of the HP C RTL Reference Manual.

   See also vsscanf and sscanf.
 

3  Return_Values

   n                  The number of successfully matched and
                      assigned input items.
   EOF                Indicates that a read error occurred before
                      any conversion. The function sets errno. For a
                      list of the values set by this function, see
                      vfscanf.
 

2  vswprintf
   Writes output to the stream under control of the wide-character
   format string.

   Format

     #include  <wchar.h>

     int vswprintf  (wchar_t *s, size_t n, const wchar_t *format,
                    va_list ap);
 

3  Arguments
 

s

   A pointer to a multibyte character sequence.
 

n

   The maximum number of bytes that comprise the multibyte
   character.
 

format

   A pointer to a wide-character string containing the format
   specifications. For more information about format and conversion
   specifications and their corresponding arguments, see the
   "Understanding Input and Output" chapter of the HP C RTL
   Reference Manual.
 

ap

   A variable list of the items needed for output.
 

3  Description
   The vswprintf function is equivalent to the swprintf function,
   with the variable argument list replaced by the ap argument.
   Initialize ap with the va_start macro, and possibly with
   subsequent va_arg calls.

   See also swprintf.
 

3  Return_Values

   n                  The number of wide characters written.
   Negative value     Indicates an error. The function sets errno to
                      one of the following:

                      o  EILSEQ - Invalid character detected.

                      o  EINVAL - Insufficient arguments.

                      o  ENOMEM - Not enough memory available for
                         conversion.

                      o  ERANGE - Floating-point calculations
                         overflow.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This might indicate that conversion to a
                         numeric value failed because of overflow.

                      The function can also set errno to the
                      following as a result of errors returned from
                      the I/O subsystem:

                      o  EBADF - The file descriptor is not valid.

                      o  EIO - I/O error.

                      o  ENOSPC - No free space on the device
                         containing the file.

                      o  ENXIO - Device does not exist.

                      o  EPIPE - Broken pipe.

                      o  ESPIPE - Illegal seek in a file opened for
                         append.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This indicates that an I/O error occurred
                         for which there is no equivalent C error
                         code.
 

2  vswscanf
   Reads input from the stream under control of the wide-character
   format string.

   Format

     #include  <wchar.h>

     int vswscanf  (wchar_t *s, const wchar_t *format, va_list ap);
 

3  Arguments
 

s

   A pointer to a wide-character string from which the input is to
   be obtained.
 

format

   A pointer to a wide-character string containing the format
   specifications.
 

ap

   A list of expressions whose results correspond to conversion
   specifications given in the format specification.
 

3  Description
   The vswscanf function is equivalent to the swscanf function,
   except that instead of being called with a variable number of
   arguments, it is called with an argument list (ap) that has been
   initialized by va_start (and possibly with subsequent va_arg
   calls).

   The vswscanf function is also equivalent to the vfwscanf
   function, except that the first argument specifies a wide-
   character string rather than a stream. Reaching the end of the
   wide-character string is the same as encountering EOF for the
   vfwscanf function.

   For more information about format and conversion specifications
   and their corresponding arguments, see the "Understanding Input
   and Output" chapter of the HP C RTL Reference Manual.

   See also vfwscanf and swscanf.
 

3  Return_Values

   n                  The number of wide characters read.
   EOF                Indicates that a read error occurred before
                      any conversion. The function sets errno. For a
                      list of the values set by this function, see
                      vfscanf.
 

2  vwprintf
   Writes output to an array of wide characters under control of the
   wide-character format string.

   Format

     #include  <wchar.h>

     int vwprintf  (const wchar_t *format, va_list ap);
 

3  Arguments
 

format

   A pointer to a wide-character string containing the format
   specifications. For more information about format and conversion
   specifications and their corresponding arguments, see the
   "Understanding Input and Output" chapter of the HP C RTL
   Reference Manual.
 

ap

   The variable list of items needed for output.
 

3  Description
   The vwprintf function is equivalent to the wprintf function,
   with the variable argument list replaced by the ap argument.
   Initialize ap with the va_start macro, and possibly with
   subsequent va_arg calls. The vwprintf function does not invoke
   the va_end macro.

   See also wprintf.
 

3  Return_Values

   x                  The number of wide characters written, not
                      counting the terminating null wide character.
   Negative value     Indicates an error. Either n or more wide
                      characters were requested to be written, or a
                      conversion error occurred, in which case errno
                      is set to EILSEQ.
 

2  vwscanf
   Reads input from an array of wide characters under control of a
   wide-character format string.

   Format

     #include  <wchar.h>

     int vwscanf  (const wchar_t *format, va_list ap);
 

3  Arguments
 

format

   A pointer to a wide-character string containing the format
   specifications.
 

ap

   A list of expressions whose resultant types correspond to the
   conversion specifications given in the format specifications.
 

3  Description
   The vwscanf function is equivalent to the wscanf function, except
   that instead of being called with a variable number of arguments,
   it is called with an argument list (ap) that has been initialized
   by va_start (and possibly with subsequent va_arg calls).

   For more information about format and conversion specifications
   and their corresponding arguments, see the "Understanding Input
   and Output" chapter of the HP C RTL Reference Manual.

   See also wscanf.
 

3  Return_Values

   n                  The number of wide characters read.
   EOF                Indicates that a read error occurred before
                      any conversion. The function sets errno. For a
                      list of the values set by this function, see
                      vfscanf.
 

2  wait
   Checks the status of the child process before exiting. A child
   process is terminated when the parent process terminates.

   Format

     #include  <wait.h>

     pid_t wait  (int *status);
 

3  Argument
 

status

   The address of a location to receive the final status of the
   terminated child. The child can set the status with the exit
   function and the parent can retrieve this value by specifying
   status.
 

3  Description
   The wait function suspends the parent process until the final
   status of a terminated child is returned from the child.

   On OpenVMS Version 7.0 and higher systems, the wait function is
   equivalent to waitpid( 0, status, 0 ) if you include <wait.h> and
   compile with the _POSIX_EXIT feature-test macro set (either with
   /DEFINE=_POSIX_EXIT or with #define _POSIX_EXIT at the top of
   your file, before any file inclusions).
 

3  Return_Values

   x                  The process ID (PID) of the terminated child.
                      If more than one child process was created,
                      wait will return the PID of the terminated
                      child that was most recently created.
                      Subsequent calls will return the PID of the
                      next most recently created, but terminated,
                      child.
   -1                 No child process was spawned.
 

2  wait3
   Waits for a child process to stop or terminate.

   Format

     #include  <wait.h>

     pid_t wait3  (int *status_location, int options, struct rusage
                  *resource_usage);
 

3  Arguments
 

status_location

   A pointer to a location that contains the termination status of
   the child process as defined in the <wait.h> header file.

   Beginning with OpenVMS Version 7.2, when compiled with the _
   VMS_WAIT macro defined, the wait3 function puts the OpenVMS
   completion code of the child process at the address specified
   in the status_location argument.
 

options

   Flags that modify the behavior of the function. These flags are
   defined in the Description section.
 

resource_usage

   The location of a structure that contains the resource
   utilization information for terminated child processes.
 

3  Description
   The wait3 function suspends the calling process until the request
   is completed, and redefines it so that only the calling thread is
   suspended.

   The options argument modifies the behavior of the function. You
   can combine the flags for the options argument by specifying
   their bitwise inclusive OR. The flags are:

   WNOWAIT        Specifies that the process whose status is
                  returned in status_location is kept in a waitable
                  state. You can wait for the process again with the
                  same results.
   WNOHANG        Prevents the suspension of the calling process.
                  If there are child processes that stopped or
                  terminated, one is chosen and the waitpid function
                  returns its process ID, as when you do not specify
                  the WNOHANG flag. If there are no terminated
                  processes (that is, if waitpid suspends the
                  calling process without the WNOHANG flag), 0
                  (zero) is returned. Because you can never wait
                  for process 0, there is no confusion arising from
                  this return.
   WUNTRACED      Specifies that the call return additional
                  information when the child processes of the
                  current process stop because the child process
                  received a SIGTTIN, SIGTTOU, SIGSTOP, or SIGTSTOP
                  signal.

   If the wait3 function returns because the status of a child
   process is available, the process ID of the child process is
   returned. Information is stored in the location pointed to by
   status_location, if this pointer is not null.

   The value stored in the location pointed to by status_location is
   0 (zero) only if the status is returned from a terminated child
   process that did one of the following:

   o  Returned 0 from the main function.

   o  Passed 0 as the status argument to the _exit or exit function.

   Regardless of the status_location value, you can define this
   information using the macros defined in the <wait.h> header file,
   which evaluate to integral expressions. In the following macro
   descriptions, the status_value argument is equal to the integer
   value pointed to by the status_location argument:

   WIFEXITED(status_  Evaluates to a nonzero value if status was
   value)             returned for a child process that terminated
                      normally.
   WEXITSTATUS(status_If the value of WIFEXITED(status_value) is
   value)             nonzero, this macro evaluates to the low-order
                      8 bits of the status argument that the child
                      process passed to the _exit or exit function,
                      or to the value the child process returned
                      from the main function.
   WIFSIGNALED(status_Evaluates to a nonzero value if status was
   value)             returned for a child process that terminated
                      due to the receipt of a signal that was not
                      intercepted.
   WTERMSIG(status_   If the value of WIFSIGNALED(status_value) is
   value)             nonzero, this macro evaluates to the number of
                      the signal that caused the termination of the
                      child process.
   WIFSTOPPED(status_ Evaluates to a nonzero value if status was
   value)             returned for a child process that is currently
                      stopped.
   WSTOPSIG(status_   If the value of WIFSTOPPED(status_value) is
   value)             nonzero, this macro evaluates to the number
                      of the signal that caused the child process to
                      stop.
   WIFCONTINUED(status_valuates to a nonzero value if status
   value)             was returned for a child process that has
                      continued.

   If the information stored at the location pointed to by status_
   location was stored there by a call to wait3 that specified
   the WUNTRACED flag, one of the following macros evaluates to a
   nonzero value:

   o  WIFEXITED(*status_value)

   o  WIFSIGNALED(*status_value)

   o  WIFSTOPPED(*status_value)

   o  WIFCONTINUED(*status_value)

   If the information stored in the location pointed to by status_
   location resulted from a call to wait3 without the WUNTRACED flag
   specified, one of the following macros evaluates to a nonzero
   value:

   o  WIFEXITED(*status_value)

   o  WIFSIGNALED(*status_value)

   The wait3 function provides compatibility with BSD systems.
   The resource_usage argument points to a location that contains
   resource usage information for the child processes as defined in
   the <resource.h> header file.

   If a parent process terminates without waiting for all of its
   child processes to terminate, the remaining child processes is
   assigned a parent process ID equal to the process ID of the init
   process.

   See also exit, -exit, and init.
 

3  Return_Values

   0                  Indicates success. There are no stopped or
                      exited child processes, the WNOHANG option is
                      specified.
   x                  The process_id of the child process. The
                      status of a child process is available.
   -1                 Indicates an error; errno is set to one of the
                      following values:

                      o  ECHILD - There are no child processes to
                         wait for.

                      o  EINTR - Terminated by receipt of a signal
                         intercepted by the calling process.

                      o  EFAULT - The status_location or resource_
                         usage argument points to a location outside
                         of the address space of the process.

                      o  EINVAL- The value of the options argument
                         is not valid.
 

2  wait4
   Waits for a child process to stop or terminate.

   Format

     #include  <wait.h>

     pid_t wait4   (pid_t process_id, union wait *status_location, 
                   int options, struct rusage *resource_usage);
 

3  Arguments
 

status_location

   A pointer to a location that contains the termination status of
   the child process as defined in the <wait.h> header file.

   Beginning with OpenVMS Version 7.2, when compiled with the _
   VMS_WAIT macro defined, the wait4 function puts the OpenVMS
   completion code of the child process at the address specified
   in the status_location argument.
 

process_id

   The child process or set of child processes.
 

options

   Flags that modify the behavior of the function. These flags are
   defined in the Description section.
 

resource_usage

   The location of a structure that contains the resource
   utilization information for terminated child processes.
 

3  Description
   The wait4 function suspends the calling process until the request
   is completed.

   The process_id argument allows the calling process to gather
   status from a specific set of child processes, according to the
   following rules:

   If the
   process_
   id is          Then status is requested

   Equal to -1    For any child process. In this respect, the
                  waitpid function is equivalent to the wait
                  function.
   Greater than   For a single child process and specifies the
   0              process ID.

   The wait4 function only returns the status of a child process
   from this set.

   The options argument to the wait4 function modifies the behavior
   of the function. You can combine the flags for the options
   argument by specifying their bitwise-inclusive OR. The flags
   are:

   WNOWAIT        Specifies that the process whose status is
                  returned in status_location is kept in a waitable
                  state. You can wait for the process again with the
                  same results.
   WNOHANG        Prevents the suspension of the calling process.
                  If there are child processes that stopped or
                  terminated, one is chosen and the waitpid function
                  returns its process ID, as when you do not specify
                  the WNOHANG flag. If there are no terminated
                  processes (that is, if waitpid suspends the
                  calling process without the WNOHANG flag), 0 is
                  returned. Because you can never wait for process
                  0, there is no confusion arising from this return.
   WUNTRACED      Specifies that the call return additional
                  information when the child processes of the
                  current process stop because the child process
                  received a SIGTTIN, SIGTTOU, SIGSTOP, or SIGTSTOP
                  signal.

   If the wait4 function returns because the status of a child
   process is available, the process ID of the child process is
   returned. Information is stored in the location pointed to by
   status_location, if this pointer is not null.

   The value stored in the location pointed to by status_location is
   0 only if the status is returned from a terminated child process
   that did one of the following:

   o  Returned 0 from the main function.

   o  Passed 0 as the status argument to the _exit or exit function.

   Regardless of the status_location value, you can define this
   information using the macros defined in the <wait.h> header file,
   which evaluate to integral expressions. In the following macro
   descriptions, status_value is equal to the integer value pointed
   to by status_location:

   WIFEXITED(status_  Evaluates to a nonzero value if status was
   value)             returned for a child process that terminated
                      normally.
   WEXITSTATUS(status_If the value of WIFEXITED(status_value) is
   value)             nonzero, this macro evaluates to the low-order
                      8 bits of the status argument that the child
                      process passed to the _exit or exit function,
                      or to the value the child process returned
                      from the main function.
   WIFSIGNALED(status_Evaluates to a nonzero value if status was
   value)             returned for a child process that terminated
                      due to the receipt of a signal that was not
                      intercepted.
   WTERMSIG(status_   If the value of WIFSIGNALED(status_value) is
   value)             nonzero, this macro evaluates to the number of
                      the signal that caused the termination of the
                      child process.
   WIFSTOPPED(status_ Evaluates to a nonzero value if status was
   value)             returned for a child process that is currently
                      stopped.
   WSTOPSIG(status_   If the value of WIFSTOPPED(status_value) is
   value)             nonzero, this macro evaluates to the number
                      of the signal that caused the child process to
                      stop.
   WIFCONTINUED(status_valuates to a nonzero value if status
   value)             was returned for a child process that has
                      continued.

   If the information stored at the location pointed to by status_
   location was stored there by a call to wait4 that specified
   the WUNTRACED flag, one of the following macros evaluates to a
   nonzero value:

   o  WIFEXITED(*status_value)

   o  WIFSIGNALED(*status_value)

   o  WIFSTOPPED(*status_value)

   o  WIFCONTINUED(*status_value)

   If the information stored in the location pointed to by status_
   location resulted from a call to wait4 without the WUNTRACED flag
   specified, one of the following macros evaluates to a nonzero
   value:

   o  WIFEXITED(*status_value)

   o  WIFSIGNALED(*status_value)

   The wait4 function is similar to the wait3 function. However,
   the wait4 function waits for a specific child as indicated by
   the process_id argument. The resource_usage argument points to a
   location that contains resource usage information for the child
   processes as defined in the <resource.h> header file.

   See also exit and _exit.
 

3  Return_Values

   0                  Indicates success. There are no stopped or
                      exited child processes, the WNOHANG option is
                      specified.
   x                  The process_id of the child process. The
                      status of a child process is available.
   -1                 Indicates an error; errno is set to one of the
                      following values:

                      o  ECHILD - There are no child processes to
                         wait for.

                      o  EINTR - Terminated by receipt of a signal
                         intercepted by the calling process.

                      o  EFAULT - The status_location or resource_
                         usage argument points to a location outside
                         of the address space of the process.

                      o  EINVAL- The value of the options argument
                         is not valid.
 

2  waitpid
   Waits for a child process to stop or terminate.

   Format

     #include  <wait.h>

     pid_t waitpid  (pid_t process_id, int *status_location, int options);
 

3  Arguments
 

process_id

   The child process or set of child processes.
 

status_location

   A pointer to a location that contains the termination status of
   the child process as defined in the <wait.h> header file.

   Beginning with OpenVMS Version 7.2, when compiled with the _
   VMS_WAIT macro defined, the waitpid function puts the OpenVMS
   completion code of the child process at the address specified in
   the status_location argument.
 

options

   Flags that modify the behavior of the function. These flags are
   defined in the Description section.
 

3  Description
   The waitpid function suspends the calling process until the
   request is completed. It is redefined so that only the calling
   thread is suspended.

   If the process_id argument is -1 and the options argument is
   0, the waitpid function behaves the same as the wait function.
   If these arguments have other values, the waitpid function is
   changed as specified by those values.

   The process_id argument allows the calling process to gather
   status from a specific set of child processes, according to the
   following rules:

   If the
   process_
   id is          Then status is requested

   Equal to -1    For any child process. In this respect, the
                  waitpid function is equivalent to the wait
                  function.
   Greater than   For a single child process and specifies the
   0              process ID.

   The waitpid function only returns the status of a child process
   from this set.

   The options argument to the waitpid function modifies the
   behavior of the function. You can combine the flags for the
   options argument by specifying their bitwise-inclusive OR. The
   flags are:

   WCONTINUED     Specifies that the following is reported to the
                  calling process: the status of any continued child
                  process specified by the process_id argument whose
                  status is unreported since it continued.
   WNOWAIT        Specifies that the process whose status is
                  returned in status_location is kept in a waitable
                  state. You can wait for the process again with the
                  same results.
   WNOHANG        Prevents the calling process from being suspended.
                  If there are child processes that stopped or
                  terminated, one is chosen and waitpid returns its
                  PID, as when you do not specify the WNOHANG flag.
                  If there are no terminated processes (that is,
                  if waitpid suspends the calling process without
                  the WNOHANG flag), 0 (zero) is returned. Because
                  you can never wait for process 0, there is no
                  confusion arising from this return.
   WUNTRACED      Specifies that the call return additional
                  information when the child processes of the
                  current process stop because the child process
                  received a SIGTTIN, SIGTTOU, SIGSTOP, or SIGTSTOP
                  signal.

   If the waitpid function returns because the status of a child
   process is available, the process ID of the child process is
   returned. Information is stored in the location pointed to by
   status_location, if this pointer is not null. The value stored
   in the location pointed to by status_location is 0 only if the
   status is returned from a terminated child process that did one
   of the following:

   o  Returned 0 from the main function.

   o  Passed 0 as the status argument to the _exit or exit function.

   Regardless of the value of status_location, you can define this
   information using the macros defined in the <wait.h> header file,
   which evaluate to integral expressions. In the following function
   descriptions, status_value is equal to the integer value pointed
   to by status_location:

   WIFEXITED(status_  Evaluates to a nonzero value if status was
   value)             returned for a child process that terminated
                      normally.
   WEXITSTATUS(status_If the value of WIFEXITED(status_value) is
   value)             nonzero, this macro evaluates to the low-order
                      8 bits of the status argument that the child
                      process passed to the _exit or exit function,
                      or to the value the child process returned
                      from the main function.
   WIFSIGNALED(status_Evaluates to a nonzero value if status
   value)             returned for a child process that terminated
                      due to the receipt of a signal not
                      intercepted.
   WTERMSIG(status_   If the value of WIFSIGNALED(status_value) is
   value)             nonzero, this macro evaluates to the number of
                      the signal that caused the termination of the
                      child process.
   WIFSTOPPED(status_ Evaluates to a nonzero value if status was
   value)             returned for a child process that is currently
                      stopped.
   WSTOPSIG(status_   If the value of WIFSTOPPED(status_value) is
   value)             nonzero, this macro evaluates to the number
                      of the signal that caused the child process to
                      stop.
   WIFCONTINUED(status_valuates to a nonzero value if status
   value)             returned for a child process that continued.

   If the information stored at the location pointed to by status_
   location is stored there by a call to waitpid that specified
   the WUNTRACED flag, one of the following macros evaluates to a
   nonzero value:

   o  WIFEXITED(*status_value)

   o  WIFSIGNALED(*status_value)

   o  WIFSTOPPED(*status_value)

   o  WIFCONTINUED(*status_value)

   If the information stored in the buffer pointed to by status_
   location resulted from a call to waitpid without the WUNTRACED
   flag specified, one of the following macros evaluates to a
   nonzero value:

   o  WIFEXITED(*status_value)

   o  WIFSIGNALED(*status_value)

   If a parent process terminates without waiting for all of its
   child processes to terminate, the remaining child processes is
   assigned a parent process ID equal to the process ID of the init
   process.

   See also exit, _exit, and wait.
 

3  Return_Values

   0                  Indicates success. If the WNOHANG option was
                      specified, and there are no stopped or exited
                      child processes, the waitpid function also
                      returns a value of 0.
   -1                 Indicates an error; errno is set to one of the
                      following values:

                      o  ECHILD-The calling process has no existing
                         unwaited-for child processes. The process
                         or process group ID specified by the
                         process_id argument does not exist or is
                         not a child process of the calling process.

                      o  EINTR-The function was terminated by
                         receipt of a signal.

                         If the waitpid function returns because
                         the status of a child process is available,
                         the process ID of the child is returned to
                         the calling process. If they return because
                         a signal was intercepted by the calling
                         process, -1 is returned.

                      o  EFAULT- The status_location argument points
                         to a location outside of the address space
                         of the process.

                      o  EINVAL- The value of the options argument
                         is not valid.
 

2  wcrtomb
   Converts the wide character to its multibyte character
   representation.

   Format

     #include  <wchar.h>

     size_t wcrtomb  (char *s, wchar_t wc, mbstate_t *ps);
 

3  Arguments
 

s

   A pointer to the resulting multibyte character.
 

wc

   A wide character.
 

ps

   A pointer to the mbstate_t object. If a NULL pointer is
   specified, the function uses its internal mbstate_t object.
   mbstate_t is an opaque datatype intended to keep the conversion
   state for the state-dependent codesets.
 

3  Description
   If s is a NULL pointer, the wcrtomb function is equivalent to the
   call:

      wcrtomb (buf, L'\0', ps)

   where buf is an internal buffer.

   If s is not a NULL pointer, the wcrtomb function determines the
   number of bytes needed to represent the multibyte character that
   corresponds to the wide character specified by wc (including any
   shift sequences), and stores the resulting bytes in the array
   whose first element is pointed to by s. At most MB_CUR_MAX bytes
   are stored.

   If wc is a null wide character, a null byte is stored preceded by
   any shift sequence needed to restore the initial shift state. The
   resulting state described is the initial conversion state.
 

3  Return_Values

   n                  The number of bytes stored in the resulting
                      array, including any shift sequences to
                      represent the multibyte character.
   -1                 Indicates an encoding error. The wc argument
                      is not a valid wide character. The global
                      errno is set to EILSEQ; the conversion state
                      is undefined.
 

2  wcscat
   Concatenates two wide-character strings.

   Format

     #include  <wchar.h>

     wchar_t *wcscat  (wchar_t *wstr_1, const wchar_t *wstr_2);
 

3  Function_Variants
   The wcscat function has variants named _wcscat32 and _wcscat64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

wstr_1, wstr_2

   Pointers to null-terminated wide-character strings.
 

3  Description
   The wcscat function appends the wide-character string wstr_2,
   including the terminating null character, to the end of wstr_1.

   See also wcsncat.
 

3  Return_Value

   x                  The first argument, wstr_1, which is assumed
                      to be large enough to hold the concatenated
                      result.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <wchar.h>
       #include <string.h>

       /* This program concatenates two wide-
character strings using */
       /* the wcscat function, and then manually compares the result */
       /* to the expected result                                     */

       #define S1LENGTH 10
       #define S2LENGTH 8

       main()
       {
           int i;
           wchar_t s1buf[S1LENGTH + S2LENGTH];
           wchar_t s2buf[S2LENGTH];
           wchar_t test1[S1LENGTH + S2LENGTH];

           /* Initialize the three wide-character strings */

           if (mbstowcs(s1buf, "abcmnexyz", S1LENGTH) == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

           if (mbstowcs(s2buf, " orthis", S2LENGTH) == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

           if (mbstowcs(test1, "abcmnexyz orthis", S1LENGTH + S2LENGTH)

               == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

       /* Concatenate s1buf with s2buf, placing the result    */
       /* into * s1buf.  Then compare s1buf with the expected */
       /* result in test1.                                    */

           wcscat(s1buf, s2buf);

           for (i = 0; i < S1LENGTH + S2LENGTH - 2; i++) {
               /* Check that each character is correct */
               if (test1[i] != s1buf[i]) {
                   printf("Error in wcscat\n");
                   exit(EXIT_FAILURE);
               }
           }

           printf("Concatenated string: <%S>\n", s1buf);
       }

     Running the example produces the following result:

       Concatenated string: <abcmnexyz orthis>
 

2  wcschr
   Scans for a wide character in a specified wide-character string.

   Format

     #include  <wchar.h>

     wchar_t *wcschr  (const wchar_t *wstr, wchar_t wc);
 

3  Function_Variants
   The wcschr function has variants named _wcschr32 and _wcschr64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

wstr

   A pointer to a null-terminated wide-character string.
 

wc

   A character of type wchar_t.
 

3  Description
   The wcschr function returns the address of the first occurrence
   of a specified wide character in a null-terminated wide-character
   string. The terminating null character is considered to be part
   of the string.

   See also wcsrchr.
 

3  Return_Values

   x                  The address of the first occurrence of the
                      specified wide character.
   NULL               Indicates that the wide character does not
                      occur in the string.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <wchar.h>
       #include <string.h>

       #define BUFF_SIZE 50

       main()
       {
           int i;
           wchar_t s1buf[BUFF_SIZE];
           wchar_t *status;

           /* Initialize the buffer */

           if (mbstowcs(s1buf, "abcdefghijkl lkjihgfedcba", BUFF_SIZE)

               == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

        /* This program checks the wcschr function by incrementally */
        /* going through a string that ascends to the middle and    */
        /* then descends towards the end.                           */

           for (i = 0; (s1buf[i] != '\0') && (s1buf[i] != ' '); i++) {
               status = wcschr(s1buf, s1buf[i]);
               /* Check for pointer to leftmost character -test 1. */
               if (status != &s1buf[i]) {
                   printf("Error in wcschr\n");
                   exit(EXIT_FAILURE);
               }
           }

           printf("Program completed successfully\n");
       }

     When this example program is run, it produces the following
     result:

       Program completed successfully
 

2  wcscmp
   Compares two wide-character strings. It returns an integer that
   indicates if the strings are different, and how they differ.

   Format

     #include  <wchar.h>

     int wcscmp  (const wchar_t *wstr_1, const wchar_t *wstr_2);
 

3  Arguments
 

wstr_1, wstr_2

   Pointers to null-terminated wide-character strings.
 

3  Description
   The wcscmp function compares the wide characters in wstr_1 with
   those in wstr_2. If the characters differ, the function returns:

   o  An integer less than 0, if the codepoint of the first
      differing character in wstr_1 is less than the codepoint of
      the corresponding character in wstr_2

   o  An integer greater than 0, if the codepoint of the first
      differing character in wstr_1 is greater than the codepoint
      of the corresponding character in wstr_2

   If the wide-characters strings are identical, the function
   returns 0.

   Unlike the wcscoll function, the wcscmp function compares the
   string based on the binary value of each wide character.

   See also wcsncmp.
 

3  Return_Values

   < 0                Indicates that wstr_1 is less than wstr_2.
   = 0                Indicates that wstr_1 equals wstr_2.
   > 0                Indicates that wstr_1 is greater than wstr_2.
 

2  wcscoll
   Compares two wide-character strings and returns an integer
   that indicates if the strings differ, and how they differ.
   The function uses the collating information in the LC_COLLATE
   category of the current locale to determine how the comparison is
   performed.

   Format

     #include  <wchar.h>

     int wcscoll  (const wchar_t *ws1, const wchar_t *ws2);
 

3  Arguments
 

ws1, ws2

   Pointers to wide-character strings.
 

3  Description
   The wcscoll function, unlike wcscmp, compares two strings in a
   locale-dependent manner. Because no value is reserved for error
   indication, the application must check for one by setting errno
   to 0 before the function call and testing it after the call.

   See also wcsxfrm.
 

3  Return_Values

   < 0                Indicates that ws1 is less than ws2.
   0                  Indicates that the strings are equal.
   > 0                Indicates that ws1 is greater than ws2.
 

2  wcscpy
   Copies the wide-character string source, including the
   terminating null character, into dest.

   Format

     #include  <wchar.h>

     wchar_t *wcscpy  (wchar_t *dest, const wchar_t *source);
 

3  Function_Variants
   The wcscpy function has variants named _wcscpy32 and _wcscpy64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

dest

   Pointer to the null-terminated wide-character destination string.
 

source

   Pointer to the null-terminated wide-character source string.
 

3  Description
   The wcscpy function copies source into dest, and stops after
   copying source's null character. If copying takes place between
   two overlapping strings, the behavior is undefined.

   See also wcsncpy.
 

3  Return_Value

   x                  The address of source.
 

2  wcscspn
   Compares the characters in a wide-character string against a
   set of wide characters. The function returns the length of the
   initial substring that is comprised entirely of characters that
   are not in the set of wide characters.

   Format

     #include  <wchar.h>

     size_t wcscspn  (const wchar_t *wstr1, const wchar_t *wstr2);
 

3  Arguments
 

wstr1

   A pointer to a null-terminated wide-character string. If this is
   a null string, 0 is returned.
 

wstr2

   A pointer to a null-terminated wide-character string that
   contains the set of wide characters for which the function will
   search.
 

3  Description
   The wcscspn function scans the wide characters in the string
   pointed to by wstr1 until it encounters a character found in
   wstr2. The function returns the length of the initial segment of
   wstr1 that is formed by characters not found in wstr2.
 

3  Return_Value

   x                  The length of the segment.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <wchar.h>
       #include <string.h>

       /* This test sets up 2 strings, buffer and w_string, and */
       /* then uses wcscspn() to calculate the maximum segment  */
       /* of w_string, which consists entirely of characters    */
       /* NOT from buffer.                                      */

       #define BUFF_SIZE 20
       #define STRING_SIZE 50

       main()
       {
           wchar_t buffer[BUFF_SIZE];
           wchar_t w_string[STRING_SIZE];
           size_t result;

           /* Initialize the buffer */

           if (mbstowcs(buffer, "abcdefg", BUFF_SIZE) == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

           /* Initialize the string */

           if (mbstowcs(w_string, "jklmabcjklabcdehjklmno", STRING_SIZE)

               == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

       /* Using wcscspn - work out the largest string in w_string */
       /* which consists entirely of characters NOT from buffer   */

           result = wcscspn(w_string, buffer);
           printf("Longest segment NOT found in w_string is: %d", result);

       }

   Running the example program produces the following result:

   Longest segment NOT found in w_string is: 4
 

2  wcsftime
   Uses date and time information stored in a tm structure to create
   a wide-character output string. The format of the output string
   is controlled by a format string.

   Format

     #include  <wchar.h>

     size_t wcsftime  (wchar_t *wcs, size_t maxsize, const char
                      *format, const struct tm *timeptr); (XPG4)

     size_t wcsftime  (wchar_t *wcs, size_t maxsize, const wchar_t
                      *format, const struct tm *timeptr); (ISO C)
 

3  Function_Variants
   Compiling with the _DECC_V4_SOURCE and _VMS_V6_SOURCE feature-
   test macros defined enables a local-time-based entry point to
   the wcsftime function that is equivalent to the behavior before
   OpenVMS Version 7.0.
 

3  Arguments
 

wcs

   A pointer to the resultant wide-character string.
 

maxsize

   The maximum number of wide characters to be stored in the
   resultant string.
 

format

   A pointer to the string that controls the format of the output
   string. For the XPG4 interface, this argument is a pointer to
   a constant character string. For the ISO C interface, it is a
   pointer to a constant wide-character string.
 

timeptr

   A pointer to the local time structure. The tm structure is
   defined in the <time.h> header file.
 

3  Description
   The wcsftime function uses data in the structure pointed to by
   timeptr to create the wide-character string pointed to by wcs. A
   maximum of maxsize wide characters is copied to wcs.

   The format string consists of zero or more conversion
   specifications and ordinary characters. All ordinary characters
   (including the terminating null character) are copied unchanged
   into the output string. A conversion specification defines how
   data in the tm structure is formatted in the output string.

   A conversion specification consists of a percent (%) character
   followed by one or more optional characters (see Optional
   Elements of wcsftime Conversion Specifications), and ending with
   a conversion specifier (see wcsftime Conversion Specifiers).
   If any of the optional characters listed in Optional Elements
   of wcsftime Conversion Specifications are specified, they must
   appear in the order shown in the table.

   Table REF-13 Optional Elements of wcsftime Conversion
                Specifications

   Element    Meaning

   -          Optional with the field width to specify that the field
              is left-justified and padded with spaces. This cannot
              be used with the 0 element.
   0          Optional with the field width to specify that the field
              is right-justified and padded with zeros. This cannot
              be used with the - element.
   field      A decimal integer that specifies the maximum field
   width      width
   .precision A decimal integer that specifies the precision of data
              in a field.

              For the d, H, I, j, m, M, o, S, U, w, W, y, and Y
              conversion specifiers, the precision specifier is the
              minimum number of digits to appear in the field. If
              the conversion specification has fewer digits than that
              specified by the precision, leading zeros are added.

              For the a, A, b, B, c, D, E, h, n, N, p, r, t, T,
              x, X, Z, and % conversion specifiers, the precision
              specifier is the maximum number of wide characters to
              appear in the field. If the conversion specification
              has more characters than that specified by the
              precision, characters are truncated on the right.

              The default precision for the d, H, I, m, M, o, S,
              U, w, W, y, and Y conversion specifiers is 2, and the
              default precision for the j conversion specifier is 3.

   Note that the list of optional elements of conversion
   specifications from Optional Elements of wcsftime Conversion
   Specifications are HP extensions to the XPG4 specification.

   wcsftime Conversion Specifiers lists the conversion specifiers.
   The wcsftime function uses fields in the LC_TIME category of
   the program's current locale to provide a value. For example, if
   %B is specified, the function accesses the mon field in LC_TIME
   to find the full month name for the month specified in the tm
   structure. The result of using invalid conversion specifiers is
   undefined.

   Table REF-14 wcsftime Conversion Specifiers

   SpecifierReplaced by

   a        The locale's abbreviated weekday name.
   A        The locale's full weekday name.
   b        The locale's abbreviated month name.
   B        The locale's full month name.
   c        The locale's appropriate date and time representation.
   C        The century number (the year divided by 100 and
            truncated to an integer) as a decimal number (00 - 99).
   d        The day of the month as a decimal number (01 - 31).
   D        Same as %m/%d/%y.
   e        The day of the month as a decimal number (1 - 31) in a
            2-digit field with the leading space character fill.
   Ec       The locale's alternative date and time representation.
   EC       The name of the base year (period) in the locale's
            alternative representation.
   Ex       The locale's alternative date representation.
   Ey       The offset from the base year (%EC) in the locale's
            alternative representation.
   EY       The locale's full alternative year representation.
   h        Same as %b.
   H        The hour (24-hour clock) as a decimal number (00 - 23).
   I        The hour (12-hour clock) as a decimal number (01 - 12).
   j        The day of the year as a decimal number (001 - 366).
   m        The month as a decimal number (01 - 12).
   M        The minute as a decimal number (00 - 59).
   n        The new-line character.
   Od       The day of the month using the locale's alternative
            numeric symbols.
   Oe       The date of the month using the locale's alternative
            numeric symbols.
   OH       The hour (24-hour clock) using the locale's alternative
            numeric symbols.
   OI       The hour (12-hour clock) using the locale's alternative
            numeric symbols.
   Om       The month using the locale's alternative numeric
            symbols.
   OM       The minutes using the locale's alternative numeric
            symbols.
   OS       The seconds using the locale's alternative numeric
            symbols.
   Ou       The weekday as a number in the locale's alternative
            representation (Monday=1).
   OU       The week number of the year (Sunday as the first day
            of the week) using the locale's alternative numeric
            symbols.
   OV       The week number of the year (Monday as the first day
            of the week) as a decimal number (01 -53) using the
            locale's alternative numeric symbols. If the week
            containing January 1 has four or more days in the new
            year, it is considered as week 1. Otherwise, it is
            considered as week 53 of the previous year, and the
            next week is week 1.
   Ow       The weekday as a number (Sunday=0) using the locale's
            alternative numeric symbols.
   OW       The week number of the year (Monday as the first day
            of the week) using the locale's alternative numeric
            symbols.
   Oy       The year without the century using the locale's
            alternative numeric symbols.
   p        The locale's equivalent of the AM/PM designations
            associated with a 12-hour clock.
   r        The time in AM/PM notation.
   R        The time in 24-hour notation (%H:%M).
   S        The second as a decimal number (00 - 61).
   t        The tab character.
   T        The time (%H:%M:%S).
   u        The weekday as a decimal number between 1 and 7
            (Monday=1).
   U        The week number of the year (the first Sunday as the
            first day of week 1) as a decimal number (00 - 53).
   V        The week number of the year (Monday as the first day
            of the week) as a decimal number (00 - 53). If the week
            containing January 1 has four or more days in the new
            year, it is considered as week 1. Otherwise, it is
            considered as week 53 of the previous year, and the
            next week is week 1.
   w        The weekday as a decimal number (0 [Sunday] - 6).
   W        The week number of the year (the first Monday as the
            first day of week 1) as a decimal number (00 - 53).
   x        The locale's appropriate date representation
   X        The locale's appropriate time representation
   y        The year without century as a decimal number (00 - 99).
   Y        The year with century as a decimal number.
   Z        Time-zone name or abbreviation. If time-zone information
            is not available, no character is output.
   %        Literal % character.
 

3  Return_Values

   x                  The number of wide characters placed into the
                      array pointed to by wcs, not including the
                      terminating null character.
   0                  Indicates an error occurred. The contents of
                      the array are indeterminate.
 

3  Example

 /* Exercise the wcsftime formatting routine.             */
 /* NOTE: the format string is an "L" (or wide character) */
 /*       string indicating that this call is NOT in      */
 /*       the XPG4 format, but rather in ISO C format.    */

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <wchar.h>
#include <locale.h>
#include <errno.h>

#define NUM_OF_DATES  7
#define BUF_SIZE 256

 /* This program formats a number of different dates, once using the   */
 /* C locale and then using the fr_FR.ISO8859-1 locale.  Date and time */
 /* formatting is done using wcsftime().                               */

main()

{
  int count,
      i;
  wchar_t buffer[BUF_SIZE];
  struct tm *tm_ptr;
  time_t time_list[NUM_OF_DATES] =
  {500, 68200000, 694223999,
   694224000, 704900000, 705000000,
   705900000};

  /* Display dates using the C locale */
  printf("\nUsing the C locale:\n\n");

  setlocale(LC_ALL, "C");

  for (i = 0; i < NUM_OF_DATES; i++) {
      /* Convert to a tm structure */
      tm_ptr = localtime(&time_list[i]);

      /* Format the date and time */
      count = wcsftime(buffer, BUF_
SIZE, L"Date: %A %d %B %Y%nTime: %T%n%n",
                      tm_ptr);
      if (count == 0) {
          perror("wcsftime");
          exit(EXIT_FAILURE);
      }

      /* Print the result */
      printf("%S", buffer);
  }

  /* Display dates using the fr_FR.ISO8859-1 locale */
  printf("\nUsing the fr_FR.ISO8859-1 locale:\n\n");

  setlocale(LC_ALL, "fr_FR.ISO8859-1");

  for (i = 0; i < NUM_OF_DATES; i++) {
      /* Convert to a tm structure */
      tm_ptr = localtime(&time_list[i]);

      /* Format the date and time */
      count = wcsftime(buffer, BUF_
SIZE, L"Date: %A %d %B %Y%nTime: %T%n%n",
                       tm_ptr);
      if (count == 0) {
          perror("wcsftime");
          exit(EXIT_FAILURE);
      }

      /* Print the result */
      printf("%S", buffer);
  }
}

   Running the example program produces the following result:

   Using the C locale:

   Date: Thursday 01 January 1970
   Time: 00:08:20

   Date: Tuesday 29 February 1972
   Time: 08:26:40

   Date: Tuesday 31 December 1991
   Time: 23:59:59

   Date: Wednesday 01 January 1992
   Time: 00:00:00

   Date: Sunday 03 May 1992
   Time: 13:33:20

   Date: Monday 04 May 1992
   Time: 17:20:00

   Date: Friday 15 May 1992
   Time: 03:20:00

   Using the fr_FR.ISO8859-1 locale:

   Date: jeudi 01 janvier 1970
   Time: 00:08:20

   Date: mardi 29 février 1972
   Time: 08:26:40

   Date: mardi 31 décembre 1991
   Time: 23:59:59

   Date: mercredi 01 janvier 1992
   Time: 00:00:00

   Date: dimanche 03 mai 1992
   Time: 13:33:20

   Date: lundi 04 mai 1992
   Time: 17:20:00

   Date: vendredi 15 mai 1992
   Time: 03:20:00
 

2  wcslen
   Returns the number of wide characters in a wide-character
   string. The returned length does not include the terminating
   null character.

   Format

     #include  <wchar.h>

     size_t wcslen  (const wchar_t *wstr);
 

3  Argument
 

wstr

   A pointer to a null-terminated wide-character string.
 

3  Return_Value

   x                  The length of the wide-character string,
                      excluding the terminating null wide character.
 

2  wcsncat
   Concatenates a counted number of wide-characters from one string
   to another.

   Format

     #include  <wchar.h>

     wchar_t *wcsncat  (wchar_t *wstr_1, const wchar_t *wstr_2,   
                       size_t maxchar);
 

3  Function_Variants
   The wcsncat function has variants named _wcsncat32 and _wcsncat64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

wstr_1, wstr_2

   Pointers to null-terminated wide-character strings.
 

maxchar

   The maximum number of wide characters from wstr_2 that are copied
   to wstr_1. If maxchar is 0, no characters are copied from wstr_2.
 

3  Description
   The wcsncat function appends wide characters from the wide-
   character string wstr_2 to the end of wstr_1, up to a maximum of
   maxchar characters. A terminating null wide character is always
   appended to the result of the wcsncat function. Therefore, the
   maximum number of wide characters that can end up in wstr_1 is
   wcslen(wstr_1) + maxchar + 1).

   See also wcscat.
 

3  Return_Value

   x                  The first argument, wstr_1, which is assumed
                      to be large enough to hold the concatenated
                      result.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <wchar.h>
       #include <string.h>

       /* This program concatenates two wide-
character strings using   */
       /* the wcsncat function, and then manually compares the result  */
       /* to the expected result                                       */

       #define S1LENGTH 10
       #define S2LENGTH 8
       #define SIZE     3

       main()
       {
           int i;
           wchar_t s1buf[S1LENGTH + S2LENGTH];
           wchar_t s2buf[S2LENGTH];
           wchar_t test1[S1LENGTH + S2LENGTH];

           /* Initialize the three wide-character strings */

           if (mbstowcs(s1buf, "abcmnexyz", S1LENGTH) == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

           if (mbstowcs(s2buf, " orthis", S2LENGTH) == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

           if (mbstowcs(test1, "abcmnexyz orthis", S1LENGTH + SIZE)

               == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

       /* Concatenate s1buf with SIZE characters from s2buf, */
       /* placing the result into s1buf. Then compare s1buf  */
       /* with the expected result in test1.                 */

           wcsncat(s1buf, s2buf, SIZE);

           for (i = 0; i <= S1LENGTH + SIZE - 2; i++) {
               /* Check that each character is correct */
               if (test1[i] != s1buf[i]) {
                   printf("Error in wcsncat\n");
                   exit(EXIT_FAILURE);
               }

           }

           printf("Concatenated string: <%S>\n", s1buf);
       }

     Running the example produces the following result:

       Concatenated string: <abcmnexyz or>
 

2  wcsncmp
   Compares not more than maxchar characters of two wide-character
   strings. It returns an integer that indicates if the strings are
   different, and how they differ.

   Format

     #include  <wchar.h>

     int wcsncmp  (const wchar_t *wstr_1, const wchar_t *wstr_2,
                  size_t maxchar);
 

3  Arguments
 

wstr_1, wstr_2

   Pointers to null-terminated wide-character strings.
 

maxchar

   The maximum number of characters to search in both wstr_1 and
   wstr_2. If maxchar is 0, no comparison is performed and 0 is
   returned (the strings are considered equal).
 

3  Description
   The strings are compared until a null character is encountered,
   the strings differ, or maxchar is reached. If characters differ,
   wcsncmp returns:

   o  An integer less than 0 if the codepoint of the first differing
      character in wstr_1 is less than the codepoint of the
      corresponding character in wstr_2

   o  An integer greater than 0 if the codepoint of the first
      differing character in wstr_1 is greater than the codepoint
      of the corresponding character in wstr_2

   If no differences are found after comparing maxchar characters,
   the function returns 0.

   See also wcscmp.
 

3  Return_Values

   < 0                Indicates that wstr_1 is less than wstr_2.
   0                  Indicates that wstr_1 equals wstr_2.
   > 0                Indicates that wstr_1 is greater than wstr_2.
 

2  wcsncpy
   Copies wide characters from source into dest. The function copies
   up to a maximum of maxchar characters.

   Format

     #include  <wchar.h>

     wchar_t *wcsncpy  (wchar_t *dest, const wchar_t *source, size_t
                       maxchar);
 

3  Function_Variants
   The wcsncpy function has variants named _wcsncpy32 and _wcsncpy64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

dest

   Pointer to the null-terminated wide-character destination string.
 

source

   Pointer to the null-terminated wide-character source string.
 

maxchar

   The maximum number of wide characters to copy from source to
   dest.
 

3  Description
   The wcsncpy function copies no more than maxchar characters from
   source to dest. If source contains less than maxchar characters,
   null characters are added to dest until maxchar characters have
   been written to dest.

   If source contains maxchar or more characters, as many characters
   as possible are copied to dest. The null terminator of source is
   not copied to dest.

   See also wcscpy.
 

3  Return_Value

   x                  The address of dest.
 

2  wcspbrk
   Searches a wide-character string for the first occurrence of one
   of a specified set of wide characters.

   Format

     #include  <wchar.h>

     wchar_t *wcspbrk  (const wchar_t *wstr, const wchar_t          
                       *charset);
 

3  Function_Variants
   The wcspbrk function has variants named _wcspbrk32 and _wcspbrk64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

wstr

   A pointer to a wide-character string. If this is a null string,
   NULL is returned.
 

charset

   A pointer to a wide-character string containing the set of wide
   characters for which the function will search.
 

3  Description
   The wcspbrk function scans the wide characters in the string,
   stops when it encounters a wide character found in charset, and
   returns the address of the first character in the string that
   appears in the character set.
 

3  Return_Values

   x                  The address of the first wide character in the
                      string that is in the set.
   NULL               Indicates that none of the characters are in
                      charset.
 

2  wcsrchr
   Scans for the last occurrence of a wide character in a given
   string.

   Format

     #include  <wchar.h>

     wchar_t *wcsrchr  (const wchar_t *wstr, wchar_t wc);
 

3  Function_Variants
   The wcsrchr function has variants named _wcsrchr32 and _wcsrchr64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

wstr

   A pointer to a null-terminated wide-character string.
 

wc

   A character of type wchar_t.
 

3  Description
   The wcsrchr function returns the address of the last occurrence
   of a given wide character in a null-terminated wide-character
   string. The terminating null character is considered to be part
   of the string.

   See also wcschr.
 

3  Return_Values

   x                  The address of the last occurrence of the
                      specified wide character.
   NULL               Indicates that the wide character does not
                      occur in the string.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <wchar.h>
       #include <string.h>

       #define BUFF_SIZE 50
       #define STRING_SIZE 6

       main()
       {
           int i;
           wchar_t s1buf[BUFF_SIZE],
                   w_string[STRING_SIZE];
           wchar_t *status;
           wchar_t *pbuf = s1buf;

           /* Initialize the buffer */

           if (mbstowcs(s1buf, "hijklabcdefg ytuhijklfedcba", BUFF_SIZE)

               == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

           /* Initialize the string to be searched for */

           if (mbstowcs(w_string, "hijkl", STRING_SIZE) == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
          }

       /* This program checks the wcsrchr function by searching for */
       /* the last occurrence of a string in the buffer s1buf and   */
       /* prints out the contents of s1buff from the location of
       /* the string found.                                         */

           status = wcsrchr(s1buf, w_string[0]);
       /* Check for pointer to start of rightmost character string. */
           if (status == pbuf) {
               printf("Error in wcsrchr\n");
               exit(EXIT_FAILURE);
           }

           printf("Program completed successfully\n");
           printf("String found : [%S]\n", status);

       }

     Running the example produces the following result:

       Program completed successfully
       String found : [hijklfedcba]
 

2  wcsrtombs
   Converts a sequence of wide characters into a sequence of
   corresponding multibyte characters.

   Format

     #include  <wchar.h>

     size_t wcsrtombs  (char *dst, const wchar_t **src, size_t len,
                       mbstate_t *ps);
 

3  Function_Variants
   The wcsrtombs function has variants named _wcsrtombs32 and
   _wcsrtombs64 for use with 32-bit and 64-bit pointer sizes,
   respectively.
 

3  Arguments
 

dst

   A pointer to the destination array for converted multibyte
   character sequence.
 

src

   An address of the pointer to an array containing the sequence of
   wide characters to be converted.
 

len

   The maximum number of bytes that can be stored in the array
   pointed to by dst.
 

ps

   A pointer to the mbstate_t object. If a NULL pointer is
   specified, the function uses its internal mbstate_t object.
   mbstate_t is an opaque datatype intended to keep the conversion
   state for the state-dependent codesets.
 

3  Description
   The wcsrtombs function converts a sequence of wide characters
   from the array indirectly pointed to by src into a sequence of
   corresponding multibyte characters, beginning in the conversion
   state described by the object pointed to by ps.

   If dst is a not a NULL pointer, the converted characters are then
   stored into the array pointed to by dst. Conversion continues up
   to and including a terminating null wide character, which is also
   stored.

   Conversion stops earlier in two cases:

   o  When a code is reached that does not correspond to a valid
      multibyte character

   o  If dst is not a NULL pointer, when the next multibyte
      character would exceed the limit of len total bytes to be
      stored into the array pointed to by dst

   Each conversion takes place as if by a call to the wcrtomb
   function.

   If dst is not a NULL pointer, the pointer object pointed to by
   src is assigned either a NULL pointer (if the conversion stopped
   because it reached a terminating null wide character) or the
   address just beyond the last wide character converted (if any).
   If conversion stopped because it reached a terminating null
   wide character, the resulting state described is the initial
   conversion state.

   If the wcsrtombs function is called as a counting function,
   which means that dst is a NULL pointer, the value of the internal
   mbstate_t object will remain unchanged.

   See also wcrtomb.
 

3  Return_Values

   x                  The number of bytes stored in the resulting
                      array, not including the terminating null (if
                      any).
   -1                 Indicates an encoding error-a character that
                      does not correspond to a valid multibyte
                      character was encountered; errno is set to
                      EILSEQ; the conversion state is undefined.
 

2  wcsspn
   Compares the characters in a wide-character string against a set
   of wide characters. The function returns the length of the first
   substring comprised entirely of characters in the set of wide
   characters.

   Format

     #include  <wchar.h>

     size_t wcsspn  (const wchar_t *wstr1, const wchar_t *wstr2);
 

3  Arguments
 

wstr1

   A pointer to a null-terminated wide-character string. If this
   string is a null string, 0 is returned.
 

wstr2

   A pointer to a null-terminated wide-character string that
   contains the set of wide characters for which the function will
   search.
 

3  Description
   The wcsspn function scans the wide characters in the wide-
   character string pointed to by wstr1 until it encounters a
   character not found in wstr2. The function returns the length of
   the first segment of wstr1 formed by characters found in wstr2.
 

3  Return_Value

   x                  The length of the segment.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <wchar.h>
       #include <string.h>

       /* This test sets up 2 strings, buffer and w_string. It */
       /* then uses wcsspn() to calculate the maximum segment  */
       /* of w_string that consists entirely of characters     */
       /* from buffer.                                         */

       #define BUFF_SIZE 20
       #define STRING_SIZE 50

       main()
       {
           wchar_t buffer[BUFF_SIZE];
           wchar_t w_string[STRING_SIZE];
           size_t result;

           /* Initialize the buffer */

           if (mbstowcs(buffer, "abcdefg", BUFF_SIZE) == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

           /* Initialize the string */

           if (mbstowcs(w_
string, "abcedjklmabcjklabcdehjkl", STRING_SIZE)

               == (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }

       /* Using wcsspn - work out the largest string in w_string */
       /* that consists entirely of characters from buffer       */

           result = wcsspn(w_string, buffer);
           printf("Longest segment found in w_
string is: %d", result);

       }

   Running the example program produces the following result:

   Longest segment found in w_string is: 5
 

2  wcsstr
   Locates the first occurrence in the string pointed to by s1 of
   the sequence of wide characters in the string pointed to by s2.

   Format

     #include  <wchar.h>

     wchar_t *wcsstr  (const wchar_t *s1, const wchar_t *s2);
 

3  Function_Variants
   The wcsstr function has variants named _wcsstr32 and _wcsstr64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

s1, s2

   Pointers to null-terminated, wide-character strings.
 

3  Description
   If s2 points to a wide-character string of 0 length, the wcsstr
   function returns s1.
 

3  Return_Values

   x                  A pointer to the located string.
   NULL               Indicates an error; the string was not found.
 

2  wcstod
   Converts a given wide-character string to a double-precision
   number.

   Format

     #include  <wchar.h>

     double wcstod  (const wchar_t *nptr, wchar_t **endptr);
 

3  Arguments
 

nptr

   A pointer to the wide-character string to be converted to a
   double-precision number.
 

endptr

   The address of an object where the function can store the address
   of the first unrecognized wide character that terminates the
   scan. If endptr is a NULL pointer, the address of the first
   unrecognized wide character is not retained.
 

3  Description
   The wcstod function recognizes an optional sequence of white-
   space characters (as defined by iswspace), then an optional plus
   or minus sign, then a sequence of digits optionally containing a
   radix character, then an optional letter (e or E) followed by an
   optionally signed integer. The first unrecognized character ends
   the conversion.

   The string is interpreted by the same rules used to interpret
   floating constants.

   The radix character is defined in the program's current locale
   (category LC_NUMERIC).

   This function returns the converted value. For wcstod, overflows
   are accounted for in the following manner:

   o  If the correct value causes an overflow, HUGE_VAL (with a plus
      or minus sign according to the sign of the value) is returned
      and errno is set to ERANGE.

   o  If the correct value causes an underflow, 0 is returned and
      errno is set to ERANGE.

   If the string starts with an unrecognized wide character, *endptr
   is set to nptr and a 0 value is returned.
 

3  Return_Values

   x                  The converted string.
   0                  Indicates the conversion could not be
                      performed. The function sets errno to one
                      of:

                      o  EINVAL - No conversion could be performed.

                      o  ERANGE - The value would cause an
                         underflow.

                      o  ENOMEM - Not enough memory available for
                         internal conversion buffer.

   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
 

2  wcstok
   Locates text tokens in a given wide-character string.

   Format

     #include  <wchar.h>

     wchar_t *wcstok  (wchar_t *ws1, const wchar_t *ws2); (XPG4)

     wchar_t *wcstok  (wchar_t *ws1, const wchar_t *ws2, wchar_t
                      **ptr); (ISO C)
 

3  Function_Variants
   The wcstok function has variants named _wcstok32 and _wcstok64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

ws1

   A pointer to a wide-character string containing zero or more text
   tokens.
 

ws2

   A pointer to a separator string consisting of one or more wide
   characters. The separator string can differ from call to call.
 

ptr

   ISO C Standard only. Used only when ws1 is NULL, ptr is a caller-
   provided wchar_t pointer into which wcstok stores information
   necessary for it to continue scanning the same wide-character
   string.
 

3  Description
   A sequence of calls to wcstok breaks the wide-character string
   pointed to by ws1 into a sequence of tokens, each of which is
   delimited by a wide character from the wide-character string
   pointed to by ws2.

   The wcstok function keeps track of its position in the wide-
   character string between calls and, as successive calls are made,
   the function works through the wide-character string, identifying
   the text token following the one identified by the previous call.

   Tokens in ws1 are delimited by null characters that wcstok
   inserts into ws1. Therefore, ws1 cannot be a const object.

   The following sections describe differences between the XPG4
   Standard and ISO C Standard interface to wcstok.

   XPG4 Standard Behavior

   The first call to the wcstok function searches the wide-character
   string for the first character that is not found in the separator
   string pointed to by ws2. The first call returns a pointer to the
   first wide character in the first token and writes a null wide
   character into ws1 immediately following the returned token.

   Subsequent calls to wcstok search for a wide character that is
   in the separator string pointed to by ws2. Each subsequent call
   (with the value of the first argument remaining NULL) returns a
   pointer to the next token in the string originally pointed to by
   ws1. When no tokens remain in the string, wcstok returns a NULL
   pointer.

   ISO C Standard Behavior

   For the first call in the sequence, ws1 points to a wide-
   character string. In subsequent calls for the same string, ws1
   is NULL. When ws1 is NULL, the value pointed to by ptr matches
   that stored by the previous call for the same wide-character
   string. Otherwise, the value pointed to by ptr is ignored.

   The first call in the sequence searches the wide-character
   string pointed to by ws1 for the first wide character that is not
   contained in the current separator wide-character string pointed
   to by ws2. If no such wide character is found, then there are no
   tokens in the wide-character string pointed to by ws1, and wcstok
   returns a NULL pointer.

   The wcstok function then searches from there for a wide character
   that is contained in the current separator wide-character string.
   If no such wide character is found, the current token extends
   to the end of the wide-character string pointed to by ws1, and
   subsequent searches in the same wide-character string for a token
   return a NULL pointer. If such a wide character is found, it
   is overwritten by a null wide character, which terminates the
   current token.

   In all cases, wcstok stores sufficient information in the pointer
   pointed to by ptr so that subsequent calls with a NULL pointer
   for ws1 and the unmodified pointer value for ptr start searching
   just past the element overwritten by a null wide character (if
   any).
 

3  Return_Values

   x                  A pointer to the first character of a token.
   NULL               Indicates that no token was found.
 

3  Examples

   1./* XPG4 version of wcstok call */

     #include <wchar.h>
     #include <string.h>
     #include <stdio.h>

     main()
     {
         wchar_t str[] = L"...ab..cd,,ef.hi";

         printf("|%S|\n", wcstok(str, L"."));
         printf("|%S|\n", wcstok(NULL, L","));
         printf("|%S|\n", wcstok(NULL, L",."));
         printf("|%S|\n", wcstok(NULL, L",."));
     }

   2./* ISO C version of wcstok call */

     #include <wchar.h>
     #include <string.h>
     #include <stdio.h>

     main()
     {
         wchar_t str[] = L"...ab..cd,,ef.hi";
         wchar_t *savptr = NULL;

         printf("|%S|\n", wcstok(str, L".", &savptr));
         printf("|%S|\n", wcstok(NULL, L",", &savptr));
         printf("|%S|\n", wcstok(NULL, L",.", &savptr));
         printf("|%S|\n", wcstok(NULL, L",.", &savptr));
     }

   Running this example produces the following results:

   $ $ RUN WCSTOK_EXAMPLE
   |ab|
   |.cd|
   |ef|
   |hi|
   $
 

2  wcstol
   Converts a wide-character string in a specified base to a long
   integer value.

   Format

     #include  <wchar.h>

     long int wcstol  (const wchar_t *nptr, wchar_t **endptr, int base);
 

3  Function_Variants
   The wcstol function has variants named _wcstol32 and _wcstol64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

nptr

   A pointer to the wide-character string to be converted to a long
   integer.
 

endptr

   The address of an object where the function can store a pointer
   to the first unrecognized character encountered in the conversion
   process (the character that follows the last character processed
   in the string being converted). If endptr is a NULL pointer, the
   address of the first unrecognized character is not retained.
 

base

   The value, 2 through 36, to use as the base for the conversion.

   If base is 16, leading zeros after the optional sign are ignored,
   and 0x or 0X is ignored.

   If base is 0, the sequence of characters is interpreted by the
   same rules used to interpret an integer constant. After the
   optional sign:

   o  A leading 0 indicates octal conversion.

   o  A leading 0x or 0X indicates hexadecimal conversion.

   o  Any other combination of leading characters indicates decimal
      conversion.
 

3  Description
   The wcstol function recognizes strings in various formats,
   depending on the value of the base. This function ignores any
   leading white-space characters (as defined by the iswspace
   function) in the given string. It recognizes an optional plus
   or minus sign, then a sequence of digits or letters that can
   represent an integer constant according to the value of the base.
   The first unrecognized character ends the conversion.
 

3  Return_Values

   x                  The converted value.
   0                  Indicates that the string starts with an
                      unrecognized wide character or that the value
                      for base is invalid. If the string starts with
                      an unrecognized wide character, *endptr is set
                      to nptr. The function sets errno to EINVAL.
   LONG_MAX or LONG_  Indicates that the converted value would cause
   MIN                a positive or negative overflow, respectively.
                      The function sets errno to ERANGE.
 

2  wcstombs
   Converts a sequence of wide-character codes to a sequence of
   multibyte characters.

   Format

     #include  <stdlib.h>

     size_t wcstombs  (char *s, const wchar_t *pwcs, size_t n);
 

3  Arguments
 

s

   A pointer to the array containing the resulting multibyte
   characters.
 

pwcs

   A pointer to the array containing the sequence of wide-character
   codes.
 

n

   The maximum number of bytes to be stored in the array pointed to
   by s.
 

3  Description
   The wcstombs function converts a sequence of codes corresponding
   to multibyte characters from the array pointed to by pwcs to a
   sequence of multibyte characters that are stored into the array
   pointed to by s, up to a maximum of n bytes. The value returned
   is equal to the number of characters converted or a -1 if an
   error occurred.

   This function is affected by the LC_CTYPE category of the
   program's current locale.

   If s is NULL, this function call is a counting operation and n is
   ignored.

   See also wctomb.
 

3  Return_Values

   x                  The number of bytes stored in s, not including
                      the null terminating byte. If s is NULL,
                      wcstombs returns the number of bytes required
                      for the multibyte character array.
   (size_t) -1        Indicates an error occurred. The function sets
                      errno to EILSEQ - invalid character sequence,
                      or a wide-character code does not correspond
                      to a valid character.
 

2  wcstoul
   Converts the initial portion of the wide-character string pointed
   to by nptr to an unsigned long integer.

   Format

     #include  <wchar.h>

     unsigned long int wcstoul  (const wchar_t *nptr, wchar_t     
                                **endptr, int base);
 

3  Function_Variants
   The wcstoul function has variants named _wcstoul32 and _wcstoul64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

nptr

   A pointer to the wide-character string to be converted to an
   unsigned long.
 

endptr

   The address of an object where the function can store the address
   of the first unrecognized character encountered in the conversion
   process (the character that follows the last character in the
   string being converted). If endptr is a NULL pointer, the address
   of the first unrecognized character is not retained.
 

base

   The value, 2 through 36, to use as the base for the conversion.

   If base is 16, leading zeros after the optional sign are ignored,
   and 0x or 0X is ignored.

   If base is 0, the sequence of characters is interpreted by
   the same rules used to interpret an integer constant: after
   the optional sign, a leading 0 indicates octal conversion, a
   leading 0x or 0X indicates hexadecimal conversion, and any other
   combination of leading characters indicates decimal conversion.
 

3  Description
   The wcstoul function recognizes strings in various formats,
   depending on the value of the base. It ignores any leading
   white-space characters (as defined by the iswspace function)
   in the string. It recognizes an optional plus or minus sign,
   then a sequence of digits or letters that may represent an
   integer constant according to the value of the base. The first
   unrecognized wide character ends the conversion.
 

3  Return_Values

   x                  The converted value.
   0                  Indicates that the string starts with an
                      unrecognized wide character or that the value
                      for base is invalid. If the string starts with
                      an unrecognized wide character, *endptr is set
                      to nptr. The function sets errno to EINVAL.
   ULONG_MAX          Indicates that the converted value would
                      cause an overflow. The function sets errno
                      to ERANGE.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <wchar.h>
       #include <errno.h>
       #include <limits.h>

       /* This test calls wcstoul() to convert a string to an     */
       /* unsigned long integer. wcstoul outputs the resulting    */
       /* integer and any characters that could not be converted. */

       #define MAX_STRING 128

       main()
       {

           int base = 10,
               errno;
           char *input_string = "1234.56";
           wchar_t string_array[MAX_STRING],
                  *ptr;
           size_t size;
           unsigned long int val;
           printf("base = [%d]\n", base);
           printf("String to convert = %s\n", input_string);
         if ((size = mbstowcs(string_array, input_string, MAX_STRING)) ==

               (size_t)-1) {

               perror("mbstowcs");
               exit(EXIT_FAILURE);
           }
           printf("wchar_t string is = [%S]\n", string_array);

           errno = 0;
           val = wcstoul(string_array, &ptr, base);
           if (errno == 0) {
       printf("returned unsigned long int from wcstoul = [%u]\n", val);
             printf("wide char terminating scan(ptr) = [%S]\n\n", ptr);
           }
           if (errno == ERANGE) {
               perror("error value is :");
               printf("ULONG_MAX = [%u]\n", ULONG_MAX);
               printf("wcstoul failed, val = [%d]\n\n", val);
           }

       }

   Running the example program produces the following result:

   base = [10]
   String to convert = 1234.56
   wchar_t string is = [1234.56]
   returned unsigned long int from wcstoul = [1234]
   wide char terminating scan(ptr) = [.56]
 

2  wcswcs
   Locates the first occurrence in the string pointed to by wstr1
   of the sequence of wide characters in the string pointed to by
   wstr2.

   Format

     #include  <wchar.h>

     wchar_t *wcswcs  (const wchar_t *wstr1, const wchar_t *wstr2);
 

3  Function_Variants
   The wcswcs function has variants named _wcswcs32 and _wcswcs64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

wstr1, wstr2

   Pointers to null-terminated wide-character strings.
 

3  Return_Values

   Pointer            A pointer to the located wide-character
                      string.
   NULL               Indicates that the wide-character string was
                      not found.
 

3  Example

       #include <stdlib.h>
       #include <stdio.h>
       #include <wchar.h>

       /* This test uses wcswcs() to find the occurrence of each */
       /* subwide-character string, string1 and string2, within  */
       /* the main wide-character string, lookin.                */

       #define BUF_SIZE 50

       main()
       {
         static char lookin[] = "that this is a test was at the end";

         char string1[] = "this",
              string2[] = "the end";

         wchar_t buffer[BUF_SIZE],
                 input_buffer[BUF_SIZE];

         /* Convert lookin to wide-character format.         */
         /* Buffer and print it out.                         */

         if (mbstowcs(buffer, lookin, BUF_SIZE) == (size_t)-1) {

             perror("mbstowcs");
             exit(EXIT_FAILURE);
         }

         printf("Buffer to look in: %S\n", buffer);

         /* Convert string1 to wide-character format and use */
         /* wcswcs() to locate it within buffer              */

         if (mbstowcs(input_buffer, string1, BUF_SIZE) == (size_t)-1) {

             perror("mbstowcs");
             exit(EXIT_FAILURE);
         }

         printf("this: %S\n", wcswcs(buffer, input_buffer));

         /* Convert string2 to wide-character format and use */
         /* wcswcs() to locate it within buffer              */

         if (mbstowcs(input_buffer, string2, BUF_SIZE) == (size_t)-1) {

             perror("mbstowcs");
             exit(EXIT_FAILURE);
         }
         printf("the end: %S\n", wcswcs(buffer, input_buffer));

         exit(1);
       }

   Running this example produces the following results:

   Buffer to look in: that this is a test was at the end
   this: this is a test was at the end
   the end: the end
 

2  wcswidth
   Determines the number of printing positions on a display device
   that are required for a wide-character string.

   Format

     #include  <wchar.h>

     int wcswidth  (const wchar_t *pwcs, size_t n);
 

3  Arguments
 

pwcs

   A pointer to a wide-character string.
 

n

   The maximum number of characters in the string.
 

3  Description
   The wcswidth function returns the number of printing positions
   required to display the first n characters of the string pointed
   to by pwcs. If there are less than n wide characters in the
   string, the function returns the number of positions required
   for the whole string.
 

3  Return_Values

   x                  The number of printing positions required.
   0                  If pwcs is a null character.
   -1                 Indicates that one (or more) of the wide
                      characters in the string pointed to by pwcs
                      is not a printable character.
 

2  wcsxfrm
   Changes a wide-character string such that the changed string can
   be passed to the wcscmp function and produce the same result as
   passing the unchanged string to the wcscoll function.

   Format

     #include  <wchar.h>

     size_t wcsxfrm  (wchar_t *ws1, const wchar_t *ws2, size_t  
                     maxchar);
 

3  Arguments
 

ws1, ws2

   Pointers to wide-character strings.
 

maxchar

   The maximum number of wide characters, including the null wide-
   character terminator, allowed to be stored in s1.
 

3  Description
   The wcsxfrm function transforms the string pointed to by ws2
   and stores the resulting string in the array pointed to by ws1.
   No more than maxchar wide characters, including the null wide
   terminator, are placed into the array pointed to by ws1.

   If the value of maxchar is less than the required size to store
   the transformed string (including the terminating null), the
   contents of the array pointed to by ws1 is indeterminate. In such
   a case, the function returns the size of the transformed string.

   If maxchar is 0, then, ws1 is allowed to be a NULL pointer, and
   the function returns the required size of the ws1 array before
   making the transformation.

   The wide-character string comparison functions, wcscoll and
   wcscmp, can produce different results given the same two wide-
   character strings to compare. This is because wcscmp does a
   straightforward comparison of the code point values of the
   characters in the strings, whereas wcscoll uses the locale
   information to do the comparison. Depending on the locale, the
   wcscoll comparison can be a multipass operation, which is slower
   than wcscmp.

   The wcsxfrm function transforms wide-character strings in such
   a way that if you pass two transformed strings to the wcscmp
   function, the result is the same as passing the two original
   strings to the wcscoll function. The wcsxfrm function is useful
   in applications that need to do a large number of comparisons on
   the same wide-character strings using wcscoll. In this case, it
   may be more efficient (depending on the locale) to transform the
   strings once using wcsxfrm and then use the wcscmp function to do
   comparisons.
 

3  Return_Values

   x                  Length of the resulting string pointed to
                      by ws1, not including the terminating null
                      character.
   (size_t) -1        Indicates that an error occurred. The function
                      sets errno to EINVAL - The string pointed to
                      by ws2 contains characters outside the domain
                      of the collating sequence.
 

3  Example

#include <wchar.h>
#include <stdio.h>
#include <stdlib.h>
#include <locale.h>

 /* This program verifies that two transformed strings,    */
 /* when passed through wcsxfrm and then compared, provide */
 /* the same result as if passed through wcscoll without   */
 /* any transformation.                                    */

#define  BUFF_SIZE  20

main()
{
    wchar_t w_string1[BUFF_SIZE];
    wchar_t w_string2[BUFF_SIZE];
    wchar_t w_string3[BUFF_SIZE];
    wchar_t w_string4[BUFF_SIZE];
    int errno;
    int coll_result;
    int wcscmp_result;
    size_t wcsxfrm_result1;
    size_t wcsxfrm_result2;

    /* setlocale to French locale */

    if (setlocale(LC_ALL, "fr_FR.ISO8859-1") == NULL) {
        perror("setlocale");
        exit(EXIT_FAILURE);
    }

    /* Convert each of the strings into wide-character format. */

    if (mbstowcs(w_string1, "<a`>bcd", BUFF_SIZE) == (size_t)-1) {

        perror("mbstowcs");
        exit(EXIT_FAILURE);
    }

    if (mbstowcs(w_string2, "abcz", BUFF_SIZE) == (size_t)-1) {

        perror("mbstowcs");
        exit(EXIT_FAILURE);
    }

    /* Collate string 1 and string 2 and store the result. */

    errno = 0;
    coll_result = wcscoll(w_string1, w_string2);
    if (errno) {
        perror("wcscoll");
        exit(EXIT_FAILURE);
    }
    else {

       /*  Transform the strings (using wcsxfrm) into  */
       /*  w_string3 and w_string4.                    */

       wcsxfrm_result1 = wcsxfrm(w_string3, w_string1, BUFF_SIZE);

       if (wcsxfrm_result1 == ((size_t) - 1))
           perror("wcsxfrm");
       else if (wcsxfrm_result1 > BUFF_SIZE) {
           perror("\n** String is too long **\n");
           exit(EXIT_FAILURE);
       }
       else {
          wcsxfrm_result2 = wcsxfrm(w_string4, w_string2, BUFF_SIZE);
          if (wcsxfrm_result2 == ((size_t) - 1)) {
              perror("wcsxfrm");
              exit(EXIT_FAILURE);
           }
          else if (wcsxfrm_result2 > BUFF_SIZE) {
              perror("\n** String is too long **\n");
              exit(EXIT_FAILURE);
           }

        /* Compare the two transformed strings and verify that  */
        /* the result is the same as the result from wcscoll on */
        /* the original strings.                                */

          else {
              wcscmp_result = wcscmp(w_string3, w_string4);
              if (wcscmp_result == 0 && (coll_result == 0)) {
                  printf("\nReturn value from wcscoll() and return value"
                                       " from wcscmp() are both zero.");
                  printf("\nThe program was successful\n\n");
              }
              else if ((wcscmp_result < 0) && (coll_result < 0)) {
                  printf("\nReturn value from wcscoll() and return value"
                                  " from wcscmp() are less than zero.");
                  printf("\nThe program was successful\n\n");
              }
              else if ((wcscmp_result > 0) && (coll_result > 0)) {
                  printf("\nReturn value from wcscoll() and return value"
                                " from wcscmp() are greater than zero.");
                  printf("\nThe program was successful\n\n");
              }
              else {
                  printf("** Error **\n");
                  printf("\nReturn values are not of the same type");
              }
           }
       }
    }
}

   Running the example program produces the following result:

   Return value from wcscoll() and return value
          from wcscmp() are less than zero.
   The program was successful
 

2  wctob
   Determines if a wide character corresponds to a single-
   byte multibyte character and returns its multibyte character
   representation.

   Format

     #include  <stdio.h>

     #include  <wchar.h>

     int wctob  (wint_t c);
 

3  Argument
 

c

   The wide character to be converted to a single-byte multibyte
   character.
 

3  Description
   The wctob function determines whether the specified wide
   character corresponds to a single-byte multibyte character when
   in the initial shift state and, if so, returns its multibyte
   character representation.
 

3  Return_Values

   x                  The single-byte representation of the wide
                      character specified.
   EOF                Indicates an error. The wide character
                      specified does not correspond to a single-byte
                      multibyte character.
 

2  wctomb
   Converts a wide character to its multibyte character
   representation.

   Format

     #include  <stdlib.h>

     int wctomb  (char *s, wchar_t wchar);
 

3  Arguments
 

s

   A pointer to the resulting multibyte character.
 

wchar

   The code for the wide character.
 

3  Description
   The wctomb function converts the wide character specified by
   wchar to its multibyte character representation. If s is NULL,
   then 0 is returned. Otherwise, the number of bytes comprising the
   multibyte character is returned. At most, MB_CUR_MAX bytes are
   stored in the array object pointed to by s.

   This function is affected by the LC_CTYPE category of the
   program's current locale.
 

3  Return_Values

   x                  The number of bytes comprising the multibyte
                      character corresponding to wchar.
   0                  If s is NULL.
   -1                 If wchar is not a valid character.
 

2  wctrans
   Returns the description of a mapping, corresponding to specified
   property, that can later be used in a call to towctrans.

   Format

     #include  <wctype.h>

     wctrans_t wctrans  (const char *property);
 

3  Argument
 

property

   The name of the mapping. The following property names are defined
   for all locales:

   o  "toupper"

   o  "tolower"

   Additional property names may also be defined in the LC_CTYPE
   category of the current locale.
 

3  Description
   The wctrans function constructs a value with type wctrans_t that
   describes a mapping between wide characters identified by the
   property argument.

   See also towctrans.
 

3  Return_Values

   nonzero            According to the LC_CTYPE category of the
                      current program locale, the string specified
                      as a property argument is the name of an
                      existing character mapping. The value returned
                      can be used in a call to the towctrans
                      function.
   0                  Indicates an error. The property argument
                      does not identify a character mapping in the
                      current program's locale.
 

2  wctype
   Used for defining a character class. The value returned by this
   function is used in calls to the iswctype function.

   Format

     #include  <wctype.h> (ISO C)

     #include  <wchar.h> (XPG4)

     wctype_t wctype  (const char *char_class);
 

3  Argument
 

char_class

   A pointer to a valid character class name.
 

3  Description
   The wctype function converts a valid character class defined for
   the current locale to an object of type wctype_t. The following
   character class names are defined for all locales:

   alnum        cntrl        lower        space
   alpha        digit        print        upper
   blank        graph        punct        xdigit

   Additional character class names may also be defined in the LC_
   CTYPE category of the current locale.

   See also iswctype.
 

3  Return_Values

   x                  An object of type wctype_t that can be used in
                      calls to the iswctype function.
   0                  If the character class name is not valid for
                      the current locale.
 

3  Example

#include <locale.h>
#include <wchar.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>

 /* This test will set up a number of character class using wctype() */
 /* and then verify whether calls to iswctype() using these classes  */
 /* produce the same results as calls to the is**** routines.        */

main()
{

    wchar_t w_char;
    wctype_t ret_val;

    char *character = "A";

    /* Convert character to wide character format - w_char */

    if (mbtowc(&w_char, character, 1) == -1) {
        perror("mbtowc");
        exit(EXIT_FAILURE);
    }

    /* Check if results from iswalnum() matches check on */
    /* alnum character class                             */

    if ((iswalnum((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("alnum"))))
        printf("[%C] is a member of the character class alnum\n", w_char);
 else
    printf("[%C] is not a member of the character class alnum\n", w_char);

    /* Check if results from iswalpha() matches check on */
    /* alpha character class                             */

    if ((iswalpha((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("alpha"))))
   printf("[%C] is a member of the character class alpha\n", w_char);
    else
   printf("[%C] is not a member of the character class alpha\n", w_char);

    /* Check if results from iswcntrl() matches check on */
    /* cntrl character class                             */

    if ((iswcntrl((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("cntrl"))))
    printf("[%C] is a member of the character class cntrl\n", w_char);
    else
   printf("[%C] is not a member of the character class cntrl\n", w_char);

    /* Check if results from iswdigit() matches check on */
    /* digit character class                             */

    if ((iswdigit((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("digit"))))
    printf("[%C] is a member of the character class digit\n", w_char);
    else
   printf("[%C] is not a member of the character class digit\n", w_char);

    /* Check if results from iswgraph() matches check on */
    /* graph character class                             */

    if ((iswgraph((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("graph"))))
        printf("[%C] is a member of the character class graph\n", w_char);
    else
   printf("[%C] is not a member of the character class graph\n", w_char);

    /* Check if results from iswlower() matches check on */
    /* lower character class                             */

    if ((iswlower((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("lower"))))
        printf("[%C] is a member of the character class lower\n", w_char);
    else
   printf("[%C] is not a member of the character class lower\n", w_char);

    /* Check if results from iswprint() matches check on */
    /* print character class                             */

    if ((iswprint((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("print"))))
        printf("[%C] is a member of the character class print\n", w_char);
    else
   printf("[%C] is not a member of the character class print\n", w_char);

    /* Check if results from iswpunct() matches check on */
    /* punct character class                             */

    if ((iswpunct((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("punct"))))
        printf("[%C] is a member of the character class punct\n", w_char);
    else
   printf("[%C] is not a member of the character class punct\n", w_char);

    /* Check if results from iswspace() matches check on */
    /* space character class                             */

    if ((iswspace((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("space"))))
        printf("[%C] is a member of the character class space\n", w_char);
    else
    printf("[%C] is not a member of the character class space\n", w_char);

    /* Check if results from iswupper() matches check on */
    /* upper character class                             */

    if ((iswupper((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("upper"))))
        printf("[%C] is a member of the character class upper\n", w_char);
    else
    printf("[%C] is not a member of the character class upper\n", w_char);

    /* Check if results from iswxdigit() matches check on */
    /* xdigit character class                             */

    if ((iswxdigit((wint_t) w_char)) &&
        (iswctype((wint_t) w_char, wctype("xdigit"))))
        printf("[%C] is a member of the character class xdigit\n", w_char);
    else
   printf("[%C] is not a member of the character class xdigit\n", w_char);

}

   Running this example produces the following result:

   [A] is a member of the character class alnum
   [A] is a member of the character class alpha
   [A] is not a member of the character class cntrl
   [A] is not a member of the character class digit
   [A] is a member of the character class graph
   [A] is not a member of the character class lower
   [A] is a member of the character class print
   [A] is not a member of the character class punct
   [A] is not a member of the character class space
   [A] is a member of the character class upper
   [A] is a member of the character class xdigit
 

2  wcwidth
   Determines the number of printing positions on a display device
   required for the specified wide character.

   Format

     #include  <wchar.h>

     int wcwidth  (wchar_t wc);
 

3  Argument
 

wc

   A wide character.
 

3  Description
   The wcwidth function determines the number of column positions
   needed for the specified wide character wc. The value of wc must
   be a valid wide character in the current locale.
 

3  Return_Values

   x                  The number of printing positions required for
                      wc.
   0                  If wc is a null character.
   -1                 Indicates that wc does not represent a valid
                      printing wide character.
 

2  wmemchr
   Locates the first occurrence of a specified wide character in an
   array of wide characters.

   Format

     #include  <wchar.h>

     wchar_t wmemchr  (const wchar_t *s, wchar_t c, size_t n);
 

3  Function_Variants
   The wmemchr function has variants named _wmemchr32 and _wmemchr64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

s

   A pointer to an array of wide characters to be searched.
 

c

   The wide character value to search for.
 

n

   The maximum number of wide characters in the array to be
   searched.
 

3  Description
   The wmemchr function locates the first occurrence of the
   specified wide character in the initial n wide characters of
   the array pointed to by s.
 

3  Return_Values

   x                  A pointer to the first occurrence of the wide
                      character in the array.
   NULL               The specified wide character does not occur in
                      the array.
 

2  wmemcmp
   Compares two arrays of wide characters.

   Format

     #include  <wchar.h>

     int wmemcmp  (const wchar_t *s1, const wchar_t *s2, size_t n);
 

3  Arguments
 

s1, s2

   Pointers to wide-character arrays.
 

n

   The maximum number of wide characters to be compared.
 

3  Description
   The wmemcmp function compares the first n wide characters of
   the array pointed to by s1 with the first n wide characters of
   the array pointed to by s2. The wide characters are compared not
   according to locale-dependent collation rules, but as integral
   objects of type wchar_t.
 

3  Return_Values

   0                  Arrays are equal.
   Positive value     The first array is greater than the second.
   Negative value     The first array is less than the second.
 

2  wmemcpy
   Copies a specified number of wide characters from one wide-
   character array to another.

   Format

     #include  <wchar.h>

     wchar_t wmemcpy  (wchar_t *dest, const wchar_t *source, size_t n);
 

3  Function_Variants
   The wmemcpy function has variants named _wmemcpy32 and _wmemcpy64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

dest

   A pointer to the destination array.
 

source

   A pointer to the source array.
 

n

   The number of wide characters to be copied.
 

3  Description
   The wmemcpy function copies n wide characters from the array
   pointed to by source to the array pointed to by dest.
 

3  Return_Value

   x                  The value of dest.
 

2  wmemmove
   Copies a specified number of wide characters from one wide-
   character array to another.

   Format

     #include  <wchar.h>

     wchar_t wmemmove  (wchar_t *dest, const wchar_t *source, size_t n);
 

3  Function_Variants
   The wmemmove function has variants named _wmemmove32 and 
   _wmemmove64 for use with 32-bit and 64-bit pointer sizes,
   respectively.
 

3  Arguments
 

dest

   A pointer to the destination array.
 

source

   A pointer to the source array.
 

n

   The number of wide characters to be moved.
 

3  Description
   The wmemmove function copies n wide characters from the location
   pointed to by source to the location pointed to by dest.

   The wmemmove and wmemcpy routines perform the same function,
   except that wmemmove ensures that the original contents of the
   source array are copied to the destination array even if the two
   arrays overlap. Where such overlap is possible, programs that
   require portability should use wmemmove, not wmemcopy.
 

3  Return_Value

   x                  The value of dest.
 

2  wmemset
   Sets a specified value to a specified number of wide characters
   in an array of wide characters.

   Format

     #include  <wchar.h>

     wchar_t wmemset  (wchar_t *s, wchar_t c, size_t n);
 

3  Function_Variants
   The wmemset function has variants named _wmemset32 and _wmemset64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

s

   A pointer to the array of wide characters.
 

c

   The value to be placed in the first n wide characters of the
   array.
 

n

   The number of wide characters to be set to the specified value c.
 

3  Description
   The wmemset function copies the value of c into each of the first
   n wide characters of the array pointed to by s.
 

3  Return_Value

   x                  The value of s.
 

2  wprintf
   Performs formatted output from the standard output (stdout). See
   Chapter 2 for information on format specifiers.

   Format

     #include  <wchar.h>

     int wprintf  (const wchar_t *format, . . . );
 

3  Arguments
 

format

   A pointer to a wide-character string containing the format
   specifications.
 

 . . .

   Optional expressions whose resultant types correspond to
   conversion specifications given in the format specification.

   If no conversion specifications are given, the output sources can
   be omitted. Otherwise, the function calls must have exactly as
   many output sources as there are conversion specifications, and
   the conversion specifications must match the types of the output
   sources.

   Conversion specifications are matched to output sources in left-
   to-right order. Excess output pointers, if any, are ignored.
 

3  Description
   The wprintf function is equivalent to the fwprintf function with
   the stdout argument interposed before the wprintf arguments.
 

3  Return_Values

   n                  The number of wide characters written.
   Negative value     Indicates an error. The function sets errno to
                      one of the following:

                      o  EILSEQ - Invalid character detected.

                      o  EINVAL - Insufficient arguments.

                      o  ENOMEM - Not enough memory available for
                         conversion.

                      o  ERANGE - Floating-point calculations
                         overflow.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This might indicate that conversion to a
                         numeric value failed because of overflow.

                      The function can also set errno to the
                      following as a result of errors returned from
                      the I/O subsystem:

                      o  EBADF - The file descriptor is not valid.

                      o  EIO - I/O error.

                      o  ENOSPC - No free space on the device
                         containing the file.

                      o  ENXIO - Device does not exist.

                      o  EPIPE - Broken pipe.

                      o  ESPIPE - Illegal seek in a file opened for
                         append.

                      o  EVMSERR - Nontranslatable OpenVMS error.
                         vaxc$errno contains the OpenVMS error code.
                         This indicates that an I/O error occurred
                         for which there is no equivalent C error
                         code.
 

2  wrapok
   In the UNIX system environment, allows the wrapping of a word
   from the right border of the window to the beginning of the
   next line. This routine is provided only for UNIX software
   compatibility and serves no function in the OpenVMS environment.

   Format

     #include  <curses.h>

     wrapok  (WINDOW *win, bool boolf);
 

3  Arguments
 

win

   A pointer to the window.
 

boolf

   A Boolean TRUE or FALSE value. If boolf is FALSE, scrolling
   is not allowed. This is the default setting. The bool type is
   defined in the <curses.h> header file as follows:

   #define bool int
 

2  write
   Writes a specified number of bytes from a buffer to a file.

   Format

     #include  <unistd.h>

     ssize_t write  (int file_desc, void *buffer, size_t nbytes);

                    (ISO POSIX-1)

     int write  (int file_desc, void *buffer, int nbytes);

                (Compatibility)
 

3  Arguments
 

file_desc

   A file descriptor that refers to a file currently opened for
   writing or updating.
 

buffer

   The address of contiguous storage from which the output data is
   taken.
 

nbytes

   The maximum number of bytes involved in the write operation.
 

3  Description
   If the write is to an RMS record file and the buffer contains
   embedded new-line characters, more than one record may be written
   to the file. Even if there are no embedded new-line characters,
   if nbytes is greater than the maximum record size for the file,
   more than one record will be written to the file. The write
   function always generates at least one record.

   If the write is to a mailbox and the third argument, nbytes,
   specifies a length of 0, an end-of-file message is written to
   the mailbox. This occurs for mailboxes created by the application
   using SYS$CREMBX, but not for mailboxes created to implement
   POSIX pipes. For more information see the "Subprocess Functions"
   chapter of the HP C RTL Reference Manual.
 

3  Return_Values

   x                  The number of bytes written.
   -1                 Indicates errors, including undefined file
                      descriptors, illegal buffer addresses, and
                      physical I/O errors.
 

2  writev
   Writes to a file.

   Format

     #include  <uio.h>

     ssize_t writev  (int file_desc, const struct iovec *iov, int  
                     iovcnt);

     ssize_t __writev64  (int file_desc, const struct              
                         __iovec64  *iov, int iovcnt);             
                         (Integrity servers, Alpha)
 

3  Function_Variants
   The writev function has variants named _writev32 and __writev64
   for use with 32-bit and 64-bit pointer sizes, respectively.
 

3  Arguments
 

file_desc

   A file descriptor that refers to a file currently opened for
   writing or updating.
 

iov

   Array of iovec structures from which the output data is gathered.
 

iovcnt

   The number of buffers specified by the members of the iov array.
 

3  Description
   The writev function is equivalent to write but gathers the output
   data from the iovcnt buffers specified by the members of the iov
   array: iov[0], iov[1], ..., iov[iovcnt-1]. The iovcnt argument
   is valid if greater than 0 and less than or equal to {IOV_MAX},
   defined in <limits.h>.

   Each iovec entry specifies the base address and length of an area
   in memory from which data should be written. The writev function
   writes a complete area before proceeding to the next.

   If filedes refers to a regular file and all of the iov_len
   members in the array pointed to by iov are 0, writev returns 0
   and has no other effect.

   For other file types, the behavior is unspecified.

   If the sum of the iov_len values is greater than SSIZE_MAX, the
   operation fails and no data is transferred.

   Upon successful completion, writev returns the number of bytes
   actually written. Otherwise, it returns a value of -1, the file
   pointer remains unchanged, and errno is set to indicate an error.
 

3  Return_Values

   x                  The number of bytes written.
   -1                 Indicates an error. The file times do not
                      change, and the function sets errno to one of
                      the following values:

                      o  EBADF - The file_desc argument is not a
                         valid file descriptor open for writing.

                      o  EINTR - The write operation was terminated
                         due to the receipt of a signal, and no data
                         was transferred.

                      o  EINVAL - The sum of the iov_len values in
                         the iov array would overflow an ssize_t, or
                         the iovcnt argument was less than or equal
                         to 0, or greater than {IOV_MAX}.

                      o  EIO - A physical I/O error has occurred.

                      o  ENOSPC - There was no free space remaining
                         on the device containing the file.

                      o  EPIPE - An attempt is made to write to a
                         pipe or FIFO that is not open for reading
                         by any process, or that only has one end
                         open. A SIGPIPE signal will also be sent to
                         the thread.
 

2  wscanf
   Reads input from the standard input (stdin) under control of the
   wide-character format string.

   Format

     #include  <wchar.h>

     int wscanf  (const wchar_t *format, . . . );
 

3  Arguments
 

format

   A pointer to a wide-character string containing the format
   specifications.
 

 . . .

   Optional expressions whose results correspond to conversion
   specifications given in the format specification.

   If no conversion specifications are given, you can omit the input
   pointers. Otherwise, the function calls must have exactly as
   many input pointers as there are conversion specifications, and
   the conversion specifications must match the types of the input
   pointers.

   Conversion specifications are matched to input sources in left-
   to-right order. Excess input pointers, if any, are ignored.
 

3  Description
   The wscanf function is equivalent to the fwscanf function with
   the stdin arguments interposed before the wscanf arguments.
 

3  Return_Values

   n                  The number of input items assigned. The number
                      can be less than provided for, even zero, in
                      the event of an early matching failure.
   EOF                Indicates an error. An input failure occurred
                      before any conversion.
 

2  y0,y1,yn
   Compute Bessel functions of the second kind.

   This function is OpenVMS Alpha and Integrity servers only.

   Format

     #include  <math.h>

     double y0  (double x);

     float y0f  (float x);

     long double y0l  (long double x);

     double y1  (double x);

     float y1f  (float x);

     long double y1l  (long double x);

     double yn  (int n, double x);

     float ynf  (int n, float x);

     long double ynl  (int n, long double x);
 

3  Arguments
 

x

   A positive, real value.
 

n

   An integer.
 

3  Description
   The y0 functions return the value of the Bessel function of the
   second kind of order 0.

   The y1 functions return the value of the Bessel function of the
   second kind of order 1.

   The yn functions return the value of the Bessel function of the
   second kind of order n.
 

3  Return_Values

   x                  The relevant Bessel value of x of the second
                      kind.
   -HUGE_VAL          The x argument is 0.0; errno is set to ERANGE.
   NaN                The x argument is negative or NaN; errno is
                      set to EDOM.
   0                  Underflow occurred; errno is set to ERANGE.
   HUGE_VAL           Overflow occurred; errno is set to ERANGE.
 

2  Version-Dependency_Tables
   New functions are added to the HP C Run-Time Library with each
   version of HP C. These functions are implemented and shipped with
   the OpenVMS operating system, while the documentation and header
   files containing their prototypes are shipped with versions of
   the HP C compiler.

   You might have a newer version of HP C that has header files
   and documentation for C RTL functions that are not supported on
   your older OpenVMS system. For example, if your target operating
   system platform is OpenVMS Version 7.2, you cannot use HP C RTL
   functions introduced on OpenVMS Version 7.3, even though they are
   documented in this manual.

   The following tables list what HP C RTL functions are supported
   on recent OpenVMS versions. This is helpful for determining the
   functions to avoid using on your target OpenVMS platforms.
 

3  All_OpenVMS_Versions
   The following functions are available on all OpenVMS VAX, Alpha,
   and Integrity servers versions:

      abort         abs           access      acos
      alarm         asctime       asin        assert
      atan2         atan          atexit      atof
      atoi          atoll (Alpha) atol        atoq (Alpha)
      box           brk           bsearch     cabs
      calloc        ceil          cfree       chdir
      chmod         chown         clearerr    clock
      close         cosh          cos         creat
      ctermid       ctime         cuserid     decc$crtl_init
      decc$fix_time     decc$from_vms      decc$match_wild
      decc$record_read  decc$record_write  decc$set_reentrancy
      decc$to_vms       decc$translate_vms
      delete        delwin        difftime    div
      dup2          dup           ecvt        endwin
      execle        execlp        execl       execve
      execvp        execv         exit        _exit
      exp           fabs          fclose      fcvt
      fdopen        feof          ferror      fflush
      fgetc         fgetname      fgetpos     fgets
      fileno        floor         fmod        fopen
      fprintf       fputc         fputs       fread
      free          freopen       frexp       fscanf
      fseek         fsetpos       fstat       fsync
      ftell         ftime         fwait       fwrite
      gcvt          getchar       getcwd      getc
      getegid       getenv        geteuid     getgid
      getname       getpid        getppid     gets
      getuid        getw          gmtime      gsignal
      hypot         initscr       isalnum     isalpha
      isapipe       isascii       isatty      iscntrl
      isdigit       isgraph       islower     isprint
      ispunct       isspace       isupper     isxdigit
      kill          labs          ldexp       ldiv
      llabs (Alpha) lldiv(Alpha)  localeconv  localtime
      log10         log           longjmp     longname
      lseek         lwait         malloc      mblen
      mbstowcs      mbtowc        memchr      memcmp
      memcpy        memmove       memset      mkdir
      mktemp        mktime        modf        mvwin
      mv[w]addstr   newwin        nice        open
      overlay       overwrite     pause       perror
      pipe          pow           printf      putchar
      putc          puts          putw        qabs (Alpha)
      qdiv (Alpha)  qsort         raise       rand
      read          realloc       remove      rename
      rewind        sbrk          scanf       scroll
      setbuf        setgid        setjmp      setlocale
      setuid        setvbuf       sigblock    signal
      sigpause      sigstack(VAX) sigvec      sinh
      sin           sleep         sprintf     sqrt
      srand         sscanf        ssignal     stat
      strcat        strchr        strcmp      strcoll
      strcpy        strcspn       strerror    strftime
      strlen        strncat       strncmp     strncpy
      strpbrk       strrchr       strspn      strstr
      strtod        strtok        strtoll     strtol (Alpha)
      strtoq (Alpha) strtoull (Alpha)  strtoul  strtouq (Alpha)
      strxfrm       subwin        system      tanh
      tan           times         time        tmpfile
      tmpnam        toascii       tolower     _tolower
      touchwin      toupper       _toupper    ttyname
      umask         ungetc        vaxc$calloc_opt vaxc$cfree_opt
      vaxc$crtl_init    vaxc$establish vaxc$free_opt vaxc$malloc_opt
      vaxc$realloc_opt  va_arg    va_count    va_end
      va_start      va_start_1    vfork       vfprintf
      vprintf       vsprintf      wait        wcstombs
      wctomb        write         [w]addch    [w]addstr
      [w]clear      [w]clrattr    [w]clrtobot [w]clrtoeol
      [w]delch      [w]deleteln   [w]erase    [w]getch
      [w]getstr     [w]inch       [w]insch    [w]insertln
      [w]insstr     [w]move       [w]printw   [w]refresh
      [w]scanw      [w]setattr    [w]standend [w]standout
 

3  V6.2_and_Higher
   The following additional functions are available on OpenVMS VAX
   and OpenVMS Alpha Version 6.2 and higher:

      catclose     catgets      catopen      fgetwc
      fgetws       fputwc       fputws       getopt
      getwc        getwchar     iconv        iconv_close
      iconv_open   iswalnum     iswalpha     iswcntrl
      iswctype     iswdigit     iswgraph     iswlower
      iswprint     iswpunct     iswspace     iswupper
      iswxdigit    nl_langinfo  putwc        putwchar
      strnlen      strptime     towlower     towupper
      ungetwc      wcscat       wcschr       wcscmp
      wcscoll      wcscpy       wcscspn      wcsftime
      wcslen       wcsncat      wcsncmp      wcsncpy
      wcspbrk      wcsrchr      wcsspn       wcstol
      wcstoul      wcswcs       wcswidth     wcsxfrm
      wcstod       wctype       wcwidth      wcstok
 

3  V7.0_and_Higher
   The following additional functions are available on OpenVMS VAX
   and OpenVMS Alpha Version 7.0 and higher:

      basename     bcmp         bcopy        btowc
      bzero        closedir     confstr      dirname
      drand48      erand48      ffs          fpathconf
      ftruncate    ftw          fwide        fwprintf
      fwscanf      getclock     getdtablesizegetitimer
      getlogin     getpagesize  getpwnam     getpwuid
      gettimeofday index        initstate    jrand48
      lcong48      lrand48      mbrlen       mbrtowc
      mbsinit      mbsrtowcs    memccpy      mkstemp
      mmap         mprotect     mrand48      msync
      munmap       nrand48      opendir      pathconf
      pclose       popen        putenv       random
      readdir      rewinddir    rindex       rmdir
      seed48       seekdir      setenv       setitimer
      setstate     sigaction    sigaddset    sigdelset
      sigemptyset  sigfillset   sigismember  siglongjmp
      sigpending   sigprocmask  sigsetjmp    sigsuspend
      srand48      srandom      strcasecmp   strdup
      strfmon      strncasecmp  strsep       swab
      swprintf     swscanf      sysconf      telldir
      tempnam      towctrans    truncate     tzset
      ualarm       uname        unlink       unsetenv
      usleep       vfwprintf    vswprintf    vwprintf
      wait3        wait4        waitpid      wcrtomb
      wcsrtombs    wcsstr       wctob        wctrans
      wmemchr      wmemcmp      wmemcpy      wmemmove
      wmemset      wprintf      wscanf
 

3  V7.0_Alpha_and_Higher
   The following additional functions are available on OpenVMS Alpha
   Version 7.0 and higher:

      _basename32  _basename64  _bsearch32   _bsearch64
      _calloc32    _calloc64    _catgets32   _catgets64
      _ctermid32   _ctermid64   _cuserid32   _cuserid64
      _dirname32   _dirname64   _fgetname32  _fgetname64
      _fgets32     _fgets64     _fgetws32    _fgetws64
      _gcvt32      _gcvt64      _getcwd32    _getcwd64
      _getname32   _getname64   _gets32      _gets64
      _index32     _index64     _longname32  _longname64
      _malloc32    _malloc64    _mbsrtowcs32 _mbsrtowcs64

      _memccpy32   _memccpy64   _memchr32    _memchr64
      _memcpy32    _memcpy64    _memmove32   _memmove64
      _memset32    _memset64    _mktemp32    _mktemp64
      _mmap32      _mmap64      _qsort32     _qsort64
      _realloc32   _realloc64   _rindex32    _rindex64
      _strcat32    _strcat64    _strchr32    _strchr64
      _strcpy32    _strcpy64    _strdup32    _strdup64
      _strncat32   _strncat64   _strncpy32   _strncpy64
      _strpbrk32   _strpbrk64   _strptime32  _strptime64
      _strrchr32   _strrchr64   _strsep32    _strsep64
      _strstr32    _strstr64    _strtod32    _strtod64
      _strtok32    _strtok64    _strtol32    _strtol64
      _strtoll32   _strtoll64   _strtoq32    _strtoq64
      _strtoul32   _strtoul64   _strtoull32  _strtoull64
      _strtouq32   _strtouq64   _tmpnam32    _tmpnam64
      _wcscat32    _wcscat64    _wcschr32    _wcschr64
      _wcscpy32    _wcscpy64    _wcsncat32   _wcsncat64
      _wcsncpy32   _wcsncpy64   _wcspbrk32   _wcspbrk64
      _wcsrchr32   _wcsrchr64   _wcsrtombs32 _wcsrtombs64
      _wcsstr32    _wcsstr64    _wcstok32    _wcstok64
      _wcstol32    _wcstol64    _wcstoul32   _wcstoul64
      _wcswcs32    _wcswcs64    _wmemchr32   _wmemchr64
      _wmemcpy32   _wmemcpy64   _wmemmove32  _wmemmove64
      _wmemset32   _wmemset64
 

3  V7.2_and_Higher
   The following additional functions are available on OpenVMS VAX
   and OpenVMS Alpha Version 7.2 and higher:

      asctime_r      ctime_r     decc$set_child_standard_streams
      decc$write_eof_to_mbx      decc$validated lclose
      dlerror        dlopen      dlsym
      fcntl          gmtime_r    localtime_r
      wchar
 

3  V7.3_and_Higher
   The following additional functions are available on OpenVMS VAX
   and OpenVMS Alpha Version 7.3 and higher:

      fchown
      link
      utime
      utimes
      writev
 

3  V7.3-1_and_Higher
   The following additional functions are available on OpenVMS Alpha
   Version 7.3-1 and higher:

      access     fseeko
      chmod      ftello
      chown      ftw
      fstat      readdir_r
                 stat

      vfscanf    vfwscanf
      vscanf     vwscanf
      vsscanf    vswscanf

      decc$feature_get_index
      decc$feature_get_name
      decc$feature_get_value
      decc$feature_set_value
 

3  V7.3-2_and_Higher
   The following additional functions are available on OpenVMS Alpha
   Version 7.3-2 and higher:

   a64l           clock_getres   clock_gettime    clock_settime
   endgrent       getgrent       getgrgid         getgrgid_r
   getgrnam       getgrnam_r     getpgid          getpgrp
   _getpwnam64    getpwnam_r     _getpwnam_r64    _getpwent64
   getpwuid       _getpwuid64    getpwuid_r       _getpwuid_r64
   getsid         l64a           nanosleep        poll
   pread          pwrite         rand_r           readv
   _readv64       seteuid        setgrent         setpgid
   setpgrp        setregid       setreuid         setsid
   sighold        sigignore      sigrelse         sigtimedwait
   sigwait        sigwaitinfo    snprintf         ttyname_r
   vsnprintf      __writev64     decc$set_child_default_dir
 

3  V8.2_and_Higher
   The following additional functions are available on OpenVMS Alpha
   and Integrity servers Version 8.2 and higher:

   clearerr_unlocked    feof_unlocked
   ferror_unlocked      fgetc_unlocked
   fputc_unlocked       flockfile
   ftrylockfile         funlockfile
   getc_unlocked        getchar_unlocked
   putc_unlocked        putchar_unlocked
   statvfs              fstatvfs
   _glob32              _glob64
   _globfree32          _globfree64
   socketpair
 

3  V8.3_and_Higher
   The following additional functions are available on OpenVMS Alpha
   and Integrity servers Version 8.3 and higher:

   crypt       fchmod
   encrypt     lstat
   setkey      readlink
   lchown      symlink
   realpath    unlink
 

3  V8.4_and_Higher
   The following additional functions are available on OpenVMS Alpha
   and Integrity servers Version 8.4 and higher:

   ftok              sem_init
   semctl            sem_open
   semget            sem_post
   semop             sem_timedwait
   sem_close         sem_trywait
   sem_destroy       sem_unlink
   sem_getvalue      sem_wait
 

2  Prototypes_Duplicated_to_Nonstandard_Headers
   The various standards dictate which header file must define
   each of the standard functions. This is the included header file
   documented with each function prototype in the Reference Section
   of this manual.

   However, many of the functions defined by the standards already
   existed on several operating systems and were defined in
   different header files. This is especially true on OpenVMS
   systems with the header files <processes.h>, <unixio.h>, and
   <unixlib.h>.

   So, to provide upward compatibility for these functions, their
   prototypes are duplicated in both the expected header file as
   well as the header file defined by the standards.

   Duplicated Prototypes lists these functions.

   Table B-1 Duplicated Prototypes

                Duplicated
   Function     in            Standard says

   access       <unixio.h>    <unistd.h>
   alarm        <signal.h>    <unistd.h>
   bcmp         <string.h>    <strings.h>
   bcopy        <string.h>    <strings.h>
   bzero        <string.h>    <strings.h>
   chdir        <unixio.h>    <unistd.h>
   chmod        <unixio.h>    <stat.h>
   chown        <unixio.h>    <unistd.h>
   close        <unixio.h>    <unistd.h>
   creat        <unixio.h>    <fcntl.h>
   ctermid      <stdio.h>     <unistd.h>
   cuserid      <stdio.h>     <unistd.h>
   dirname      <string.h>    <libgen.h>
   dup          <unixio.h>    <unistd.h>
   dup2         <unixio.h>    <unistd.h>
   ecvt         <unixlib.h>   <stdlib.h>
   execl        <processes.h> <unistd.h>
   execle       <processes.h> <unistd.h>
   execlp       <processes.h> <unistd.h>
   execv        <processes.h> <unistd.h>
   execve       <processes.h> <unistd.h>
   execvp       <processes.h> <unistd.h>
   _exit        <stdlib.h>    <unistd.h>
   fcvt         <unixlib.h>   <stdlib.h>
   ffs          <string.h>    <strings.h>
   fsync        <stdio.h>     <unistd.h>
   ftime        <time.h>      <timeb.h>
   gcvt         <unixlib.h>   <stdlib.h>
   getcwd       <unixlib.h>   <unistd.h>
   getegid      <unixlib.h>   <unistd.h>
   getenv       <unixlib.h>   <stdlib.h>
   geteuid      <unixlib.h>   <unistd.h>
   getgid       <unixlib.h>   <unistd.h>
   getopt       <stdio.h>     <unistd.h>
   getpid       <unixlib.h>   <unistd.h>
   getppid      <unixlib.h>   <unistd.h>
   getuid       <unixlib.h>   <unistd.h>
   index        <string.h>    <strings.h>
   isatty       <unixio.h>    <unistd.h>
   lseek        <unixio.h>    <unistd.h>
   mkdir        <unixlib.h>   <stat.h>
   mktemp       <unixio.h>    <stdlib.h>
   nice         <stdlib.h>    <unistd.h>
   open         <unixio.h>    <fcntl.h>
   pause        <signal.h>    <unistd.h>
   pipe         <processes.h> <unistd.h>
   read         <unixio.h>    <unistd.h>
   rindex       <string.h>    <strings.h>
   sbrk         <stdlib.h>    <unistd.h>
   setgid       <unixlib.h>   <unistd.h>
   setuid       <unixlib.h>   <unistd.h>
   sleep        <signal.h>    <unistd.h>
   strcasecmp   <string.h>    <strings.h>
   strncasecmp  <string.h>    <strings.h>
   system       <processes.h> <stdlib.h>
   times        <time.h>      <times.h>
   umask        <stdlib.h>    <stat.h>
   vfork        <processes.h> <unistd.h>
   wait         <processes.h> <wait.h>
   write        <unixio.h>    <unistd.h>