Writes informational and error messages to processes.

    On Alpha and Integrity server systems, this service accepts 64-
    bit addresses.

                                   NOTE

       The return value from *actrtn is checked to determine
       whether or not the message is output.

    Format

      SYS$PUTMSG  msgvec ,[actrtn] ,[facnam] ,[actprm]

    C Prototype

      int sys$putmsg  (void *msgvec, int (*actrtn)(__unknown_params),

                      void *facnam, unsigned __int64 actprm);