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Debugging SIGKILL when opening app after multitasking quit

Hi everyone,

I'm having some trouble trying to debug a complication with an application I'm working on.

Now, we've not added any multitasking functionality - infact most of it is as Xcode creates it. However, if I launch the app in the simulator, quit the app completely (via the double home button tap) then launch it again it all falls over with a SIGKILL complaint.

The thing that's really causing me a problem is that all of the crash reports and profiling methods all seem to stop 'following' the app once I fully quit it and thus I get no feedback about what's causing the application to crash.

Am I missing something?

Thanks.
Greg.

Macbook Pro, Mac OS X (10.6.6)

Posted on Mar 19, 2011 9:18 AM

Best reply

xnav

Level 5

7,089 points

Posted on Mar 19, 2011 1:43 PM

Are you sure about when you get SIGKILL? When you double-tap Home and remove an app from the task list the mechanism used by iOS to stop it is a SIGKILL of the process.

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22 replies

xnav

Level 5

7,089 points

Mar 21, 2011 2:36 PM in response to GregularExpressions

Sorry, I have no other ideas unless you are running some 3rd party kernel extensions or system level software on all 3 machines.

xnav

Level 5

7,089 points

Mar 21, 2011 4:01 PM in response to GregularExpressions

There are others with your issue. Do as KT always advises and search for SIGKILL on https://devforums.apple.com/community/ios

Mar 22, 2011 2:55 AM in response to xnav

Thanks Xnav, I did as you suggested and found numerous threads mentioning similar issues but unfortunately with no apparent fixes 😟

As one of the moderators suggested in the developer forums I have submitted a bug report to Apple.

Thanks again for your help.

Mac Jim ID

Level 6

9,327 points

Mar 22, 2011 2:08 PM in response to GregularExpressions

I get the same thing with my tab bar App.
- Launch with Xcode 4 and run in simulator.
- Quit App with Home button.
- Double Tap Home to bring up running Apps.
- Hold finger on App and tap X to quit running.
- Relaunch by tapping App in Simulator and SigKill crash in Xcode on the Main() run loop.

No Errors logged by App, but there is the "Error deserializing wallpaper image" error seen by running "Console" that is caused by the "SpringBoard" process.

Have seen no solution,
Jim

Mac Jim ID

Level 6

9,327 points

Mar 22, 2011 2:32 PM in response to Mac Jim ID

After further research it appears to be normal behavior. The SigKill comes up since the App was ran by Xcode and the process was stopped by "SpringBoard". The debugger catches the kill in Xcode after it is ran again from "Springboard". If you continue from the debugger the App will run as usual.
Also, you can launch the App in Xcode until the App comes up, then Stop the App in Xcode. You can then run the App in simulator and quit it as described above without the error on relaunch. You won't get the debugging information that stopped the App previously.

The issue was explained by Rincewind on the Apple Developer Forums.

Hope this helps your situation.

Mar 22, 2011 4:00 PM in response to Mac Jim ID

Hi Jim,

Thanks for your contributions, I'll mark it as solved.

Greg.

simon3ds

Level 1

0 points

Apr 29, 2011 1:05 AM in response to GregularExpressions

I have the exact same issue since the last update of Xcode4 + 4.3 (simulator + device) and I'm sorry but it's not an acceptable answer nor a solved problem.

I mean there is absolutly no reason to be satisfied with "it's a normal behavior" when we all know that it was NOT happening on the previous versions of Xcode.

I'm going to reinstall Xcode 3 for now.

Debugging SIGKILL when opening app after multitasking quit