[zeromq-dev] PUB socket, EPGM and zmq_poll()

Jim Hague jim.hague at acm.org
Wed Nov 25 19:07:41 CET 2015

Hi all,

I'm using a PUB socket with EPGM to multicast low volume data to clients 
listening with a SUB. The sender listens for incoming data on a PULL socket, 
which it integrates into an existing event loop by adding underlying fds from 
zmq_getsockopt(ZMQ_FD) into the event loop, and when one fires checking 
activity with zmq_poll().

I have found that the sender is not reacting to PGM NAKs. A bit of googling 
suggests that the sender needs to call pgm_recv() to trigger sending the NAK 

So I'm guessing that I need to include the fd for the PUB socket in the event 
loop. Does that sound right? I guess I may also need to check for incoming 
data on the PUB socket? If so, do I need to do a zmq_recv() on the PUB socket 
to trigger the NAK processing, or will the zmq_poll() do the necessary?

Jim Hague - jim.hague at acm.org          Never trust a computer you can't lift.

More information about the zeromq-dev mailing list