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How to understand the accident log on Xcode 4

I am trying to debug the cause of my application to crash. From my research, I realized that there are leaks somewhere, and I'm in the middle of finding out. I knew this because when I tried to debug this method here , it would eventually crash, as it seems like a memory leak is building up after a while.

To find out the reason, I now opened NSZombieEnabled for YES on Xcode 4. But I did not see anything. So now I turn to the crash log. And here he is:

Thread 7 Crashed: 0 libsystem_kernel.dylib 0x31b71a1c __pthread_kill + 8 1 libsystem_c.dylib 0x35ceb3b4 pthread_kill + 52 2 libsystem_c.dylib 0x35ce3bf8 abort + 72 3 libsystem_c.dylib 0x35d1f024 free + 104 4 ImageIO 0x32ca35f0 ImageProviderReleaseInfoCallback + 56 5 CoreGraphics 0x31a05284 image_provider_finalize + 8 6 CoreFoundation 0x35aad288 _CFRelease + 160 7 CoreFoundation 0x35aad1ae CFRelease + 82 8 CoreGraphics 0x319fe150 CGImageProviderRelease + 4 9 CoreGraphics 0x31a00bac CGImageBlockSetRelease + 44 10 CoreGraphics 0x31a00b70 img_blocks_destroy + 8 11 CoreGraphics 0x319fdaae CGSImageDataUnlock + 26 12 libRIP.A.dylib 0x309eebae ripc_ReleaseImage + 374 13 libRIP.A.dylib 0x309ecc9c ripc_DrawImage + 536 14 CoreGraphics 0x319f9284 CGContextDelegateDrawImage + 44 15 CoreGraphics 0x319f9142 CGContextDrawImage + 250 16 myapp 0x000c6a28 0x45000 + 530984 17 myapp 0x000c6d6a 0x45000 + 531818 18 myapp 0x000c681c 0x45000 + 530460 19 myapp 0x000c3526 0x45000 + 517414 20 myapp 0x000c3796 0x45000 + 518038 21 Foundation 0x33486382 -[NSThread main] + 38 22 Foundation 0x334f85c6 __NSThread__main__ + 966 23 libsystem_c.dylib 0x35ceb30a _pthread_start + 242 24 libsystem_c.dylib 0x35cecbb4 thread_start + 0

My question is: are there any tips on how to read and understand this debug log? Maybe a link or a book that tells how to debug everything together. Thanks.

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In this case

 2 libsystem_c.dylib 0x35ce3bf8 abort + 72 3 libsystem_c.dylib 0x35d1f024 free + 104

a free function detects that the free address is not in the heap area or is invalid, and then calls the interrupt function.

“ Technical Note TN2239 - The iOS debug mask is a very useful document. Please take a look at the“ Memory Allocator ”and use Malloc * environments such as NSZombieEnabled. Setting the break function to interrupt is also useful for getting a parameter for a free and tracking stack.

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This crash log is not a symbol, so it does not give you line numbers and object names in your application. There is a process to adding this information to the crash log to give you much more information to help debug the crash.

See http://developer.apple.com/tools/xcode/symbolizingcrashdumps.html In particular, the section on symbolizing crash dumps.

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