Perl5 リファレンス

       msgrcv ID,VAR,SIZE,TYPE,FLAGS
               Calls the System V IPC function msgrcv to receive
               a message from message queue ID into variable VAR
               with a maximum message size of SIZE.  Note that
               when a message is received, the message type as a
               native long integer will be the first thing in
               VAR, followed by the actual message.  This packing
               may be opened with `unpack("l! a*")'.  Taints the
               variable.  Returns true if successful, or false if
               there is an error.  See also `IPC::SysV' and
               `IPC::SysV::Msg' documentation.