Hello!
I'm writing an application that uses MQTT to post some sensor data to a server. My networking code is basically a duplicate of this sample, except I set up the LTE connection before starting the network loop, have a larger volume of data to transfer, and read sensor values from serial in a different thread.
Occasionally the MQTT event handler function receives MQTT_EVT_DISCONNECT with reason code 113 (ECONNABORTED) right before making a network call (mqtt_ping(), mqtt_connect(), &c.). In that case, the network call seems to hang indefinitely. I can't tell how the example application copes with this—do I have to re-run try_to_connect() immediately before every network operation? I'd be happy if the library calls just timed out, instead of blocking indefinitely. Is there a config option for that?
As far as I can see, the documentation doesn't specify any invariants I need to uphold beside "mqtt_client struct's memory shall be resident throughout the program's lifetime." Is there some condition I'm missing? I never access any part of the MQTT data structures or library from any thread besides my networking thread, and I've verified there are no deadlocks, &c. I'm certain it is the library functions that are hanging.
Thanks in advance!
—EMB