Debugging HeapReAlloc failure using GetExceptionCode

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+1 Q:

Debugging HeapReAlloc failure using GetExceptionCode

Hey folks,

Been messing about with this all day and haven't got anywhere so I'm hoping someone can help me - I have a HeapReAlloc method failing with the error ACCESS_VIOLATION, but I'm unsure how to implement a further check using GetExceptionCode as it uses try/catch or exception or something - can someone give me a quick example of how I can use it to narrow down this failure, please?

Thanks very much, Becky

Are HeapReAlloc's hHeap and lpMem valid? What value are you passing for dwFlags? Did you obtain hHeap via HeapCreate or GetProcessHeap? What parameters have you provided to HeapCreate/GetProcessHeap?

vladr 2010-04-15 14:19:28

hHeap is valid, passing HEAP_GENERATE_EXCEPTIONS | HEAP_ZERO_MEMORY for dwFlags, and lpMem is valid when I use HeapValidate just before the HeapReAlloc function call.

Becky Franklin 2010-04-15 14:26:54

I use HeapCreate with the parameters HEAP_GENERATE_EXCEPTIONS,100000,0

Becky Franklin 2010-04-15 14:30:22

@Becky, in addition to `HeapValidate(hHeap, 0, lpMem)` can you *also* call `HeapValidate(hHeap, 0, NULL)` to validate the entire heap?

vladr 2010-04-15 15:59:30

+1 A:

You are trouble-shooting the wrong problem. HeapRealloc() is bombing because the heap is corrupted. That happened a while ago, some statement in your program overflowing a heap block, writing data to memory that was freed, something like that. MSVC has a debug memory allocator to help you troubleshoot these kind of problems, look in the MSDN library for <crtdbg.h>.

Hans Passant 2010-04-15 15:48:42

ansaurus

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Debugging HeapReAlloc failure using GetExceptionCode

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