Error -23 in mqtt_connect

[Bastien42]

Good afternoon,

My device communicates using MQTT a few times a day. After many connections I noticed that communications stopped. Every connection attempt would fail with:

Error in mqtt_connect: -23.

Error code 23 corresponds to "file table overflow", therefore, I assumed that it was linked to a mishandling of sockets when connection failed.

I have now made sure that mqtt_abort() is called in any case where connection may fail and when disconnecting, and I am currently testing those changes.

Are there other causes to error -23 in mqtt_connect() ?

Best regards

Bastien

[Håkon Alseth]

Hi,

 

As seen from the code, mqtt_abort() wraps around mqtt_disconnect() with a if-sentence: 

Håkon Alseth said:

This function will only disconnect if the mqtt state is not idle:

https://github.com/nrfconnect/sdk-zephyr/blob/main/subsys/net/lib/mqtt/mqtt.c#L689-L702

 

I would recommend that you call mqtt_disconnect() directly to ensure socket cleanup.

  

Kind regards,

Håkon