[zeromq-dev] ZMQ_XPUB_VERBOSE does not report unsubscriptions

[Stefan Radomski]

Hi there,

setting the ZMQ_XPUB_VERBOSE option on an XPUB socket will only report multiple subscriptions - for unsubscription, only the last unsubscription is reported. This makes the option unusable to count actual subscribers as some might already have unsubscribed and you'd never know. Is there a reason unsubscriptions are not handled in the same manner as subscriptions? And of what use is ZMQ_XPUB_VERBOSE if I can't know the number of subscribers? 

This is not an oversight as a comment in xpub.cpp:73 reads: "[…] (Unsubscribe is not verbose.)".

Best regards
Stefan