NAME

       pvm_getminfo, pvm_setminfo - Get or set header information of a message.

SYNOPSIS

       C    int info = pvm_getminfo( int bufid, struct pvmminfo *mi )
            int info = pvm_setminfo( int bufid, struct pvmminfo *mi )

       Fortran   call pvmfgetminfo( bufid, len, ctx, tag, wid, enc, crc,
                                  src, dst, info )
            call pvmfsetminfo( bufid, ctx, tag, wid, src, dst, info )

PARAMETERS

       bufid   Message buffer identifier.

       mi      Struct containing header information.

       info    Result code.

       For a description of the Fortran parameters, see below.

DESCRIPTION

       These  functions  read and set information passed in message headers, which may be of interest to certain
       applications.  Typically, they will be used when it is necessary to get the message context or wait id to
       use the same values in a reply message.

       The fields affected are:

       len    The length in bytes of the body of the message.  This will be equal to the actual size of the data
              packed, if PvmDataRaw is used, otherwise it may include pad bytes.

       ctx    The context sent with the message.

       tag    The tag sent with the message.

       wid    Wait Identifier, used to match a reply message to the corresponding request.

       enc    Message Encoding, either the data signature of the sender, or 0x10000000 for XDR.

       crc    The CRC checksum of the message body.

       src    The tid of the sender.

       dst    The tid of the destination.

       All fields may be read, but only ctx, tag, wid, src and dst may be set.

       pvm_getmwid and pvm_setmwid return PvmOk if successful, or else a negative error code.

EXAMPLES

            /* return a message to a caller with the same tag and wait id */
            struct pvmminfo mi1, mi2;

            pvm_recv(-1, -1);
            /* ... process, compose reply message */
            pvm_getminfo(pvm_getrbuf(), &mi1);
            pvm_getminfo(pvm_getsbuf(), &mi2);
            mi2.wid = mi1.wid;
            pvm_send(mi1.src, mi1.tag);

ERRORS

       The following error conditions can be returned by pvm_getmwid or pvm_setmwid:

       PvmBadParam
              Invalid value for bufid or mi argument.

       PvmNoSuchBuf
              Message buffer bufid doesn't exist.

SEE ALSO

       pvm_bufinfo(3PVM)

                                                 13 March, 1996                                   SETMINFO(3PVM)