问题
I got a memory leak (55 bytes) on my program like this. I am using C++, MFC, Visual Studio 2010.
Detected memory leaks! {13497} normal block at 0x0E44C248, 55 bytes long. Data: 44 3A 5C 46 44 41 53....
the problem is, the memory allocation number "13497" is not always same. it's always different number if I run the program again. I wanted to find where I didn't release the memory before the exit, with _crtBreakAlloc, but it seems not possible to break on a memory allocation number. I used _CrtSetDbgFlag, and _CrtDumpMemoryLeaks as well, but it also didn't work well.
Is there any way to detect the memory leak in this case?
Thank you.
回答1:
You can use a static analizer like cppcheck or, as Joe said, remap operator new.
I developed some memory leaks utilities that you can use:
https://github.com/check69/Utils/blob/master/leaks.cpp
https://github.com/check69/Utils/blob/master/leaks.h
There is some visual studio instruction to get the leaks in the console output, to debug easier.
PS: I would put this as a comment in joe post, but I need 50 points to put comments.
回答2:
Well there are a few ways to attack this.
- Look at the dump of the data for any sort of strings you might recognize. That might help you locate it.
- Put a conditional breakpoint on memory allocations that only breaks if the size requested (or being allocated) is 55 bytes.
- You might get better results by putting something like this really early in a header that all of your code includes (like stdafx.h)
This code remaps operator new
#ifdef _DEBUG
# define _CRTDBG_MAP_ALLOC
# include <crtdbg.h>
# include <new>
# include <memory>
# define DEBUG_NEW new(_NORMAL_BLOCK, __FILE__, __LINE__)
# define new DEBUG_NEW
#endif
- Also, does the leaked memory amount go up the more you run/use your application? If not, it might not really be a leak at all. Sometimes you can get leaks reported for statically allocated objects. In the very least, take a close look at the static allocations you make
回答3:
Hello thanks for your answers..
I found the leak location very easily by using "Visual Leak detector" from https://vld.codeplex.com/ I strongly recommend this one to those who have the same problem. :) you can just download it and put it in your project.
来源：https://stackoverflow.com/questions/45666714/how-to-detect-memory-leak-when-memory-allocation-number-isnt-always-same