[zeromq-dev] Chat example not working

Martin Sustrik sustrik at 250bpm.com
Mon Jan 11 07:51:07 CET 2010

Hi Marcel,

> Unfortunately my first experience with zmq 2.0 wasn't very smooth: the 
> chat example didn't work out of the box. It seems like you recently 
> changed the semantics of the ZMQ_SUBSCRIBE option (looking at the 
> documentation on the website and implementation), but didn't adapt its 
> uses in examples/chat/display.cpp and 
> devices/zmq_forwarder/zmq_forwarder.cpp. After changing the filter from 
> "*" to "",  the chat example got functional again.

Thanks for spotting the problem. It's fixed in GIT rev. 72b2f07. We'll 
release beta2 shortly to incorporate all the fixes made since beta1.

> BTW. did you have a particular reason to let zmq_forwarder, zmq_queue 
> and zmq_streamer be separate executables? Looking at their similarity, 
> doesn't it make more sense to have a single executable that switches on 
> the root element of the configuration xml file to select forwarding, 
> queueing or streaming behavior?

Well, from the developer's point of view there's no point in keeping the 
applications separate. The code is almost the same.

However, from the user's perspective it makes sense to have different 
executables to perform different tasks IMO. As a user, feel free to 
argue about the point though.


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