logical-name
    OpenVMS usage:logical_name
    type:         character string
    access:       read only
    mechanism:    by descriptor
    Logical name to be defined or redefined. The logical-name
    argument contains the address of a descriptor pointing to this
    logical name string. The maximum length of a logical name is 255
    characters. Note that logical names are case sensitive.
 value-string
    OpenVMS usage:char_string
    type:         character string
    access:       read only
    mechanism:    by descriptor
    Value to be given to the logical name. The value-string argument
    contains the address of a descriptor pointing to this value
    string. The maximum length of a logical name value is 255
    characters.
    If omitted, an item list must be present to specify the values of
    the logical name.
 table
    OpenVMS usage:char_string
    type:         character string
    access:       read only
    mechanism:    by descriptor
    Name of the table in which to create the logical name. The table
    argument contains the address of a descriptor pointing to the
    logical name table. If no table is specified, LNM$PROCESS is used
    as the default.
 attributes
    OpenVMS usage:mask_longword
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    Logical name or translation attributes. The attributes argument
    is the address of a longword bit mask that contains the logical
    name or translation attributes.
    LNM$M_CONFINE and LNM$M_NO_ALIAS are currently available logical
    name attributes. See the description of the $CRELNM system
    service in the HP OpenVMS System Services Reference Manual: A-
    GETUAI for definitions of LNM$M_CONFINE and LNM$M_NO_ALIAS. If
    omitted, no special logical name attribute is established.
    If no item-list is specified, the translation attributes
    LNM$M_CONCEALED and LNM$M_TERMINAL may be specified. See
    the description of the ASSIGN command in the HP OpenVMS DCL
    Dictionary for definitions of these attributes. If an item-list
    is specified, it will contain the translation attributes for each
    equivalence string in the attribute.
 item-list
    OpenVMS usage:item_list_3
    type:         unspecified
    access:       read only
    mechanism:    by reference, array reference
    Item list describing the equivalence names for this logical
    name. The item-list argument contains the address of an array
    that contains this item list. If item-list is not specified,
    the logical name will have only one value, as specified in the
    value-string argument. Item codes for use with this item list are
    included in libraries supplied by HP in module $LNMDEF.
    Either value-string or item-list must be specified. If neither
    is specified, the LIB$_INVARG error is produced. If both value-
    string and item-list are specified, the value-string argument is
    ignored.
    If item-list is specified, only logical name attributes are
    permitted. Translation attributes appear in the item list.
    The item-list argument is needed only when you want to create
    multiple equivalence strings for a single logical name.