What is the Non UI role in crash reports

Question

When analysing crash reports, I'm seeing a Non UI role that I have never seen before. I am trying to understand what state of the app it corresponds to.

Hardware Model:      iPhone7,2
Code Type:           ARM-64 (Native)
Role:                Non UI
Parent Process:      launchd [1]
OS Version:          iPhone OS 11.4 (15F79)
Report Version:      104

The Role header is mentioned in the documentation here, which points to the kernel source. In the latest available version of the source (as well as previous versions), I see a TASK_NONUI_APPLICATION enum constant, but it is undocumented.

There is already a TASK_FOREGROUND_APPLICATION and a TASK_BACKGROUND_APPLICATION constant, so I don't understand what Non UI (or TASK_NONUI_APPLICATION) can be.

Varick

Answer 1

It's possible that it was launched by a a background mode? Does your app support one of the following background modes? iOS can fully launch an app into the background if it receives an event like a location notification (emphasis mine):

The system can terminate apps at any time to free up memory or other system resources. The system relaunches a terminated app only if the app has Always authorization and if it was running the significant change, visits, or region monitoring location service at the time of its termination.

Castellan