Detecting memory leaks using _CrtDumpMemoryLeaks

[hjazz]

Hi,

This is my first time using the CRT library for detecting memory leaks, and I'm using Visual C++ 2003. As mentioned in this website (http://msdn.microsoft.com/en-us/library/x98tx3cf.aspx), I included the statements in my program

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

followed by another header file that contains all other header files like stdio.h, windows.h and structure/function declarations. I also have

_CrtDumpMemoryLeaks();

right before my function returns.

When I tried to build my program, I get the errors

error C2059: syntax error: 'constant'
error C2059: syntax error: 'string'
error C2733: second C linkage of overloaded function '_aligned_malloc_dbg' not allowed

for the function prototypes in malloc.h, e.g.

_CRTIMP void * __cdecl calloc(size_t, size_t);
_CRTIMP void * __cdecl free(void *);

etc.

How do I run the memory check debugger correctly?

Thank you.

Regards,
Rayne

[ovidiucucu]

Just include <crtdbg.h> after all others.
Example

#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <string.h>
// other includes here...
#include <crtdbg.h> // keep this the last include!

int main()
{
   char* p = (char*)calloc(10, 10);
   strcpy(p, "Baba Safta");
   _CrtDumpMemoryLeaks();

   return 0;
}

Result

Detected memory leaks!
Dumping objects ->
C:\Projects\Test\Test.cpp(15) : {44} normal block at 0x00332A38, 100 bytes long.
 Data: <Baba Safta      > 42 61 62 61 20 53 61 66 74 61 00 00 00 00 00 00 
Object dump complete.

[hjazz]

Thanks. I tried that, but now I have a different error:

error LNK2001: unresolved external symbol "int __cdecl _CrtDumpMemoryLeaks(void)
error LNK2001: unresolved external symbol "__cdecl calloc_dbg(...)
error LNK2001: unresolved external symbol "__cdecl malloc_dbg(...)
error LNK2001: unresolved external symbol "__cdecl realloc_dbg(...)
error LNK2001: unresolved external symbol "__cdecl realloc_dbg(...)
error LNK2001: unresolved external symbol "__cdecl operator_new(...)
...

I don't just have one source code file. My main function is in main.c, and I'm trying to call CrtDumpMemoryLeaks() in FunctionA(), which is in FunctionA.c. This FunctionA.c has

#include FunctionA.h

And this header file is #include'd in FunctionB.c. But FunctionB() does not call CrtDumpMemoryLeaks().

So what I have in FunctionA.h is

#ifndef FUNCTIONA_H
#define FUNCTIONA_H

#define _CRTDBG_MAP_ALLOC

typedef unsigned __int8 uint8_t;
typedef unsigned char u_char;
typedef unsigned short u_short;

#include <WinSock2.h>
#include <windows.h>
#include <stdlib.h>
#include <stdio.h>
#incldue <pcap-int.h>
#include <string.h>
#include <strsafe.h>
#include <signal.h>
#include <time.h>

#include "FunctionC.h"
#include "FunctionD.h"

#include <crtdbg.h>

// Other #define
// Other extern variables
// Structure declarations
// Function declarations

#endif

I'm also trying to build this as a dll.