Question

I am working on a C project in MSVS 2010 (meaning I am using malloc, calloc, and free, not the C++ new and delete operators). I need to find a memory leak(s?), so I’ve followed the steps on http://msdn.microsoft.com/en-us/library/x98tx3cf.aspx to get the program to dump the memory state at the end of the run.

I include the libraries like so:

#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>

I also specify that every exit should display the debug info like so:

_CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );

But my debug output looks like this:

Detected memory leaks!
Dumping objects ->
{80181} normal block at 0x016B1D38, 12 bytes long.
 Data: <  7   7 8 7 > 0C D5 37 00 14 A9 37 00 38 99 37 00 
{80168} normal block at 0x016ACC20, 16 bytes long.
 Data: <  7 H 7 X 7 \ 7 > A8 FB 37 00 48 E9 37 00 58 C2 37 00 5C AC 37 00 
...

According to the article, I should be getting file name and line number output indicating where the leaked memory is allocated. Why is this not happening, and how can I fix it?

Answer 1

Adrian McCarthy commented that I should ensure that the definition _CRT_MAP_ALLOC existed in every compilation unit. While I could not figure out how to define that as a compiler option, I did create a sparse header file that I ensured every compiled file included. This made the debugging functionality work as expected.