The Show Virtual Memory Statistics routine returns the statistics
    accumulated from calls to LIB$GET_VM/LIB$FREE_VM and LIB$GET_VM_
    PAGE/LIB$FREE_VM_PAGE.

    Format

      LIB$SHOW_VM  [code] [,user-action-procedure]

                   [,user-specified-argument]

1  –  Returns

    OpenVMS usage:cond_value
    type:         longword (unsigned)
    access:       write only
    mechanism:    by value

2  –  Arguments

 code

    OpenVMS usage:longword_signed
    type:         longword integer (signed)
    access:       read only
    mechanism:    by reference

    Code specifying any one of the statistics to be written to
    SYS$OUTPUT or passed to an action routine for processing.
    The code argument is the address of a signed longword integer
    containing the statistic code. This is an optional argument. If
    the statistic code is omitted or is zero, statistics for values
    1, 2, and 3 are returned on one line.

    The following values are allowed for the code argument:

    Value Statistic

    0     Statistics for values 1, 2, and 3 are returned.
    1     Number of successful calls to LIB$GET_VM.
    2     Number of successful calls to LIB$FREE_VM.
    3     Number of bytes allocated by LIB$GET_VM but not yet
          deallocated by LIB$FREE_VM.
    4     Statistics for values 5, 6, and 7 are returned.
    5     Number of calls to LIB$GET_VM_PAGE.
    6     Number of calls to LIB$FREE_VM_PAGE.
    7     Number of VAX pages or Alpha pagelets allocated by LIB$GET_
          VM_PAGE but not yet deallocated by LIB$FREE_VM_PAGE.

 user-action-procedure

    OpenVMS usage:procedure
    type:         procedure value
    access:       function call (before return)
    mechanism:    by value

    User-supplied action routine called by LIB$SHOW_VM. By default,
    LIB$SHOW_VM returns statistics to SYS$OUTPUT. An action routine
    is useful when you want to return statistics to a file or, in
    general, to any place other than SYS$OUTPUT. The routine returns
    either a success or failure condition value, which will be
    returned as the value of LIB$SHOW_VM.

 user-specified-argument

    OpenVMS usage:user_arg
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value

    A 32-bit value to be passed directly to the action routine
    without interpretation. That is, the contents of the argument
    list entry user-specified-argument are copied to the argument
    list entry for user-action-procedure.