Detect a memory leak with code on Windows by define _CRTDBG_MAP_ALLOC macros

With the memory leak detection tool in VS, to enable memory leak detection, include the following statement in your program:

#define _CRTDBG_MAP_ALLOC
#include <crtdbg.h>

Their order of precedence cannot be changed. By including Crtdbg.h, the malloc and free functions are mapped to their "Debug" version _malloc_dbg and _free_dbg, which track memory allocation and release. This mapping occurs only in the debug version (where _DEBUG is defined). #define语句将CRT堆函数的基版本映射到对应的 "Debug" version.

The test code is as follows:

#include <iostream>

#ifdef _DEBUG
	#define Debug_clientblock   New (_client_block, __file__, __line__ )
#else
	#define Debug_clientblock
#endif

#ifdef _DEBUG
	#define _CRTDBG_MAP_ALLOC
	#include <crtdbg.h>

	#define NEW Debug_clientblock
#endif

void Test_c ()
{
	int* p = (int*) malloc ( sizeof (int));

	Free (p);
}

void Test_cpp ()
{
	int* p = new INT[10];

	delete [] p;
}

int main ()
{
	_CrtSetDbgFlag (_crtdbg_alloc_mem_df | _crtdbg_leak_check_df);//_crtdumpmemoryleaks ()
	; _CrtSetReportMode (_crt_error, _crtdbg_mode_debug);

	Test_c ();
	Test_cpp ();

	Std::cout << "OK" << Std::endl;
}

The result diagram is as follows:

GitHub: https://github.com/fengbingchun/Messy_Test