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Can I use information from my program’s crash log:

Thread 0 Crashed: 0 libobjc.A.dylib 0x908311ec objc_msgSend + 0xc 1 …nyridgesoftware.validinator 0x0000a888 -[AuvalOutputController dealloc] + 0x4c 2 0x9019440c __CFArrayReleaseValues + 0x214

to identify a line of source code? I know that something in AuvalOutputController’s dealloc method crashed while attempting to send a message, but that’s as much as I know how to decipher. I’m using Xcode 1.5.

If you can reproduce the crash, simply run your executable in the debugger, then the debugger will stop at the erroneous line and show a stack dump, where you can see the context of each stack frame.

Though I can say with 90% certainty that the crash you are seeing is because you send a message to a deallocated object.

Either look over the code for dealloc or read NSZombieEnabled for some advice to catch this type of error.


Are you using a Development build or otherwise generating debugging symbols? If so, you should get a filename & line number at the end of the crash log line.

I think I’m generating debugging symbols. In the Build Style options “Generate Debug Symbols” is checked and “Level of Debug Symbols” is set to All Symbols. Are you saying that I should see the filename and line number at the end of each line of the above sample? If so, I wonder what other options I need to set.

How about the optimization level? Mine is set to None (-O0)

Now I’m getting line numbers. I didn’t think I changed anything, but apparently I did. Maybe I inadvertently had the wrong build type set. Oh well…

A couple days after I posted the original question, Apple was kind enough to include a reference to a tech note about Crash Reporter in the ADC mailing. It doesn’t talk about using this information in the context of Xcode, but there is some useful info there nonetheless.

Here’s something I figured out: the atos command-line utility described in the tech note requires Zerolink to be disabled.


Ummm…in my experience, the error you posted above usually means that the program crashed before it even got to your code (i.e., objc_msgSend was probably trying to send a message to one of your methods). When you get an error in your code you do get the line numbers. –JediKnil

The original stack trace does have his code in there - the second line. Looks like his crash is coming from a stripped executable, hence no line numbers. His code is trying to do an objc_msgSend on something bad. Were It My Code, I’d look at my -dealloc and see what I’m doing there. Then use atos to map the address back into the program (assuming you have the original program with debug symbols)

Yeah, you’re right, sorry about that. If I had to guess offhand, I would agree with you about the build settings. Perhaps the build mode was set to Deployment instead of Development…or something to that effect. I guess I’m not being too helpful. –JediKnil

The best cocoadev page for stuff like this is DebuggingTechniques. atos is described in a tech note linked from there, and there are many other techniques.