msgid

    OpenVMS usage:cond_value
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Identification of the message to be retrieved. The msgid argument
    is a longword value containing the message identification. Each
    message has a unique identification, contained in bits 3 through
    27 of system longword condition values.

 msglen

    OpenVMS usage:word_unsigned
    type:         word (unsigned)
    access:       write only
    mechanism:    by 32- or 64-bit reference
    Length of the message string returned by $GETMSG. The msglen
    argument is the 32- or 64-bit address of a word into which
    $GETMSG writes this length.

 bufadr

    OpenVMS usage:char_string
    type:         character-coded text string
    access:       write only
    mechanism:    by 32- or 64-bit descriptor-fixed-length string
                  descriptor
    Buffer to receive the message string. The bufadr argument is the
    32- or 64-bit address of a character string descriptor pointing
    to the buffer into which $GETMSG writes the message string. The
    maximum size of any message string is 256 bytes.

 flags

    OpenVMS usage:mask_longword
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Message components to be returned. The flags argument is a
    longword bit vector wherein a bit, when set, specifies that the
    message component is to be returned.

    The following table describes the significant bits:

    Bit  Value   Description

    0    1       Include text of message
         0       Do not include text of message
    1    1       Include message identifier
         0       Do not include message identifier
    2    1       Include severity indicator
         0       Do not include severity indicator
    3    1       Include facility name
         0       Do not include facility name

    If you omit this argument in a VAX MACRO or BLISS-32 service
    call, it defaults to a value of 15; that is, all flags are set
    and all components of the message are returned. If you omit this
    argument in a Fortran service call, it defaults to a value of 0;
    the value 0 causes $GETMSG to use the process default flags.

 outadr

    OpenVMS usage:vector_byte_unsigned
    type:         byte (unsigned)
    access:       write only
    mechanism:    by 32- or 64-bit reference
    Optional information to be returned by $GETMSG. The outadr
    argument is the 32- or 64-bit address of a 4-byte array into
    which $GETMSG writes the following information:

    Byte   Contents

    0      Reserved
    1      Count of FAO arguments associated with message
    2      User-specified value in message, if any
    3      Reserved