If you have ever asked how can I debug releasing/alloc issues in objective-c, you will have came across these environment settings that can help track the problem down:

  • NSZombieEnabled - Keeps abjects around after release, so you can get pointers etc.
  • MallocStackLogging - keeps object history for reference later
  • NSDebugEnabled

You set all of these to YES in the 'environment' section of the 'arguments' tab in the 'executables' (found in group tree) info.

So, Im getting this console output

MyApp [4413:40b] -[CALayer retainCount]: message sent to deallocated instance 0x4dbb170

then open terminal, while the debugger has forwarded the break and type:

malloc_history 4413 0x4dbb170

Then, I get a big text dump, and as far as I understand the important bit is this:

1

ALLOC 0x4dbb160-0x4dbb171 [size=18]:
thread_a0375540 |start | main |
UIApplicationMain | GSEventRun |
GSEventRunModal | CFRunLoopRunInMode |
CFRunLoopRunSpecific | __CFRunLoopRun
| __CFRunLoopDoTimer |
__CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__
| __NSFireDelayedPerform |
-[todoListViewController drillDocumentMenu:] |
-[documentListViewController drillIntoDocumentWithToDoRecord:] |
-[documentViewController OpenTodoDocument:OfType:WithPath:] |
-[documentViewController OpenDocumentOfType:WithPath:] |
-[documentViewController managePDFDocumentWithPath:] |
-[PDFDocument loadPDFDocumentWithPath:andTitle:] |
-[PDFDocument getMetaData] | CGPDFDictionaryApplyFunction |
ListDictionaryObjects(char const*,
CGPDFObject*, void*) | NSLog | NSLogv
| _CFLogvEx | __CFLogCString |
asl_send | _asl_send_level_message |
asl_set_query | strdup | malloc |
malloc_zone_malloc

2

FREE  0x4dbb160-0x4d
objective-c ios malloc-history
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