[mosquitto-dev] qos 1 callbacks and memory management

[Anto Nello <hbrain@xxxxxxxxx>]

Hello guys,

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

Regards

MP