[zeromq-dev] Other poll events than in/out

Martin Sustrik sustrik at 250bpm.com
Mon Feb 15 10:15:18 CET 2010


> * For zmq sockets only io/out events make sense.  But what about for
> other socket types.  Can zmq_poll be used to monitor other sockets for
> the other events that select/poll know about?

Yes. Native sockets support error event in addition to in & out. This 
should be added. There's already a ticket for this (ZMQII-71) so it's on 
my todo list. However, adding ZMQ_POLLERR to the header files, passing 
it to the underlying poll/select function (zmq.cpp) and retrieving the 
result should be pretty easy in case you want to have to fix it ASAP.

> * When working with zmq sockets, does zmq_poll know about when
> complete messages are ready to be sent or received, or when the
> underlying socket is ready for read/write?

It's concerned with complete messages.

> * In the IO thread, does zmq call the real poll/select and manage the
> tcp/tpc/etc sockets in a non-blocking manner?

The poll is called in application thread. It polls on raw sockets 
supplied to zmq_poll and for a single socket delivering notifications 
from I/O threads.


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