Perl5 リファレンス

       msgsnd ID,MSG,FLAGS
               Calls the System V IPC function msgsnd to send the
               message MSG to the message queue ID.  MSG must
               begin with the native long integer message type,
               and be followed by the length of the actual
               message, and finally the message itself.  This
               kind of packing can be achieved with `pack("l!
               a*", $type, $message)'.  Returns true if
               successful, or false if there is an error.  See
               also `IPC::SysV' and `IPC::SysV::Msg'