Excellent description of PMQ & System V queues in "Unix Network
   Programming Vol 2" by W. Richard Stevens.
   Quote:
   1. A read on a PMQ always returns the oldest message of the highest
   priority, whereas SystemV can return a
   message of any desired priority.
   2. PMQ's allow the generation of a signal or the initiation of a thread
   when a message is placed on an empty queue,
   whereas nothing similar is provided by SystemV massage queues.
   Inactive hide details for ibc---11/07/2012 22:17:18---Hi, according to
   the doc: "POSIX message queues allow local processes to
   ibc---11/07/2012 22:17:18---Hi, according to the doc: "POSIX message
   queues allow local processes to exchange data in the

   [cid:2__=4EBBF0AADFAC31398f9e8a93d@bnpparibas.com]

   [ruby.posix.mq] Posix Message Queue vs System V Message Queue
(Internet)
ibc

          A :
              ruby.posix.mq

                                                                                  11/07/2012 22:17

   Envoye par: ruby.posix.mq@librelist.org
   Veuillez repondre `a ruby.posix.mq
   _______________________________________________________________________

   Hi, according to the doc:
   "POSIX message queues allow local processes to exchange data in the
   form of messages. This API is distinct from that provided by System V
   message queues, but provides similar functionality."
   My Ruby project [*] uses posix_mq Gem heavily. The "problem" is that
   Posix mq is not supported in OSX (not a real problem for me but... you
   know). So I wonder, which is the advantage of Posix MQ over System V
   MQ?
   And... does Ruby (1.9) include support for System V mq? I've found a
   project:
    [1]http://sysvipc.rubyforge.org/
   but it seems that it does not provide a like-IO object in the way
   posix_mq provides, so I cannot properly integrate it with EventMachine
   (I did it for EM: [2]https://github.com/ibc/em-posixmq).
   Thanks a lot for any explanation.
   [*] [3]https://github.com/versatica/OverSIP
   --
   Inaki Baz Castillo
   <ibc@aliax.net>
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References

   1. http://sysvipc.rubyforge.org/
   2. https://github.com/ibc/em-posixmq
   3. https://github.com/versatica/OverSIP