Xcode 4.2 jumps to main.m every time after stopping simulator

This is more of a general annoyance. Every time after stopping the simulator, Xcode jumps to main.m for some reason. On the left nav, it jumps to the Debug Navigator.

Is there a way to fix this?

It's annoying because I might be testing a certain line of code, and now each time, I need to make a couple of clicks just to go back to that code.

This problem is not new, seems to get worse though. At the time of writing this, I was on the GM seed, but this problem persists in XCode 4.2 final. This was not a problem in previous versions of XCode.

When we start debug from xcode, the debugger sets itself up to monitor signals from OS. When we press stop button in XCode (or hit cmd + R - which first stops existing instance running and then try to start new one, somewhat equalant to we press manually stop first and then run) SIGKILL is sent to the debugger.

Whenever the cause of interruption is from outside the app (in other words all cases where SIGKILL is sent, like stop button press) , debugger jumps to main, since main is the root of the app and the place where your app meets the OS. Debugger has no way to identify why this SIGKILL is issued (pressing stop button in xcode/ press cmd + R/ delete app from multitasking bar etc), but it treats SIGKILL as outside interrupt, and nothing related with your code. So it jumps to main.

If the cause of interruption is from inside the app (like app crash/SIGABRT) debugger handles it and jumps to the place of crash, which we normally see.

I do not consider this as an xcode bug, rather a normal way of handling SIGKILL. But if you want to stay at your code and do not want to jump to main you can do two things

1. You can do as Gabe suggested. As BBonified said, it is like a band-aide, but I think it should work (personally I never tried that)

2. Report a bug/request for a feature here. Let me tell you you are not the first one to do so. Already a bug has been reported. See this and this. But I don't have much hope of a positive action from Apple

And I agree with you, it is sometimes annoying. Especially if you have experienced differently in previous XCode versions. But we can only take what they give here.

I guess it's fair to call it a bug, Xcode 3 specifically suppressed this useless artefact.

I've had success (four times and counting) with this one-liner in ~/.gdbinit:

handle SIGKILL nostop noprint nopass

Taken from this gdb manual:

http://www.delorie.com/gnu/docs/gdb/gdb_39.html

Not sure if it applies to lldb as well.

I tried what David suggested but that didn't work for me, so I tried something similar:

1. Open Preferences, select Behaviors tab.
2. Select "Run exits unexpectedly" from left column.
3. Select "Show debugger with current views".

I'm using Xcode version 4.2 build 4D199.

EDIT: That worked for about 15 minutes. Then it reverted to bringing up main.m in the editor again.

I had the same problem and it WAS really annoying, especially when you were in the middle of debugging, stopping/launching the app several times in a row after small modifications.

Everything is solvable through settings in Xcode user preferences:

• Just go to "run completes"
• There find the "Show" line and click the checkbox
• On the same line modify target to go to "Current" in the dropdown menu.

There you go. Xcode will not move your editing view from now on. Enjoy.

PS: Xcode version 4.2 Build 4C199

Go to Preferences -> Behaviors. Choose "Run Completes" in the left hand side. Check the box next to "Show Tab" and enter a tab name. I use "Edit". This way whenever you stop, you will always be back at a tab called Edit.

None of the other solutions listed were suitable for me, so I made a macro (using an external hotkey utility).

(wait 0.1 second after each step)

command-period

command-1

down arrow

up arrow

command-j

enter

Use this key instead of the normal stop, and you end up with your cursor positioned where you left it. Very nice.

Xcode -> Preferences

Under Behaviors

Click on Run Starts

Checkbox for [Show] debugger with [Current Views]

...worked for me.

None of the preference adjustments seem to work for me.

I have been able to track the offending sequence of events. The SIGKILL error message will occur when you run your app and use multiple threads. For instance, when using UIWebView in my app it will abort to main.m. I verified that when UIWebView is not called, XCode can be stopped without the SIGKILL error message returning the user to main.m

It looks like there are at least two threads that get started when initializing a UIWebView. However, any threads created by you during the running of your app will cause the SIGKILL to improperly notify XCODE to return to the main.

You can see this in the GDB that there is a switch just before SIGKILL:

>[Switching to process 24957 thread 0x2103] > >[Switching to process 24957 thread 0x7403] > >[Switching to process 24957 thread 0x207] > >Program ended with exit code: 0

It is definitely still a bug with XCODE that will hopefully be fixed.

For now, if you avoid executing code that launches a separate thread, it will not change the view back to main.m For code that does launch additional threads, I would recommend quitting the simulator to return to edit mode in XCODE.

This might not be much. I was able to avoid this problem 99% of the time by waiting for 2 seconds or so after stopping the app, before relaunching it.

UPDATE: After upgrading to the latest Xcode, I am prompted to use LLDB instead of GDB. The problem seems to be gone now.

None of these solutions worked for me and I find the behavior too intrusive to put up with.

I get round it by using the 'Assistant Editor' instead of the editor as my main editing window. You access the Assistant Editor using the tiny little bow tie button at the top right of the single window.

You can set then it to 'Manual'. Click on the button that is the far left crumb of the breadcrumb trail at the top of the Assistant Editor frame and select Manual from the pop-up menu that appears. The Manual setting allows you to select the file you're editing by clicking on the second to last crumb of the breadcrumb trail and selecting the file from the pop-up that appears.

I then just minimize the size of the main editor - or use it as a secondary editing window, useful given that you can't split the editors into multiple frames any more. Far from ideal - but that's XCode 4 for you.

I was trying to find the offending line when my code was breaking, so what I did was:

1. Go to where you define your breakpoints (breakpoint navigator, according to the documentation)
2. Click in the "+" sign in the left bottom corner of the navigation area
3. Click on Add Exception breakpoint
4. You click Done
5. Run your app

Xcode shows you the offending line.