Main loop in Asset Tracker application

[andrew926]

Hello,

I was reading through the code of the asset tracker application and noticed that there is no while(1)/for(;;)-loop. I see this for the first time in a board application. All the other samples have a while(1)-loop. What happens after the last function call 'connect_to_cloud()'? 

[Carl Richard]

Hi, Andrew!

There is no particular need for main in NCS. In fact, some Zephyr samples doesn't have a main at all! There will still be various threads running, e.g. in the drivers and workqueues. While I don't remember all the details on how the asset_tracker does things, when the cloud responds to the connection request, a event handler will be called, which starts the next step, which triggers new events, etc.

If you want to untangle it I suggest that you look for places where threads are started (sometimes before main) and items are put in workqueues. 

Best regards,
Carl Richard

[Carl Richard]

Got some information from the developers aswell! 

In the default case where the asset tracker uses nRF Cloud, the thread handling the cloud connection is found here: https://github.com/nrfconnect/sdk-nrf/blob/6c63feff14df3da9d7171f9122d8cc66cd882bc9/subsys/net/lib/nrf_cloud/src/nrf_cloud.c#L494

The cloud event handler in asset tracker's main.c is called from this thread context

https://github.com/nrfconnect/sdk-nrf/blob/6c63feff14df3da9d7171f9122d8cc66cd882bc9/applications/asset_tracker/src/main.c#L1391

Best regards,
Carl Richard

[andrew926]

Thank you!