[zeromq-dev] zpoller and lvcache backend socket misses new subscribers to duplicate topic

Rich Schramm rich at mbari.org
Thu Mar 8 22:13:44 CET 2018

I am trying to implement lvcache from example with the czmq vsn 4.1.0. api  I want to send last value from cache to any new subscriber to a topic.  My problem is that only the first subscriber to a topic is seems to trigger an event for the backend XPUB socket in the poller_wait loop …  ie 1st client subcriber to topic “FOO” and first client subscribing to topic  “BAR” both are recognized.  A third client also starting a subscription to “FOO” doesnt appear to be detected at the poller_wait. 
Likewise, the poller also doesnt trigger again until all clients that have subscribed to ‘FOO” are killed.
Is this expected behavior and/or how can I make sure that every client subscribing is recognized and receives the topic’s initial cached value?

-Rich Schramm

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