I'm trying to create an extension of the libmosquitto in order to manage a custom application ack.
All other applications are going to communicate with the MQTT broker through my extension.
I have some questions:
1) I have seen that on_publish, on_subscribe and on_connect handlers are called both with qos=0 and qos=1.
I thought that these callbacks were only called in corrispondence of PUBACK, SUBACK and CONACK.
What am I missing?
2) How the memory is managed inside libmosquitto ?
Fastly looking at the code it seems there are internal queues.
3) What happens if the MQTT broker publishes messages on 2 or more different topics at the same time ?
Is this already managed by the lib ? It should be connected to point 2.
4) Are there blocking publish and subscribe functions inside the library ?
Thanks in advance