How to detect memory leak under windows

This article mainly introduces how to detect C/C++ memory leaks under windows related knowledge, detailed and easy to understand, simple and fast operation, with a certain reference value, I believe that everyone reading this C/C++ memory leak under windows how to detect articles will be harvested, let's take a look at it.

Detecting memory leaks

Take advantage of instrumentation provided by Visual Studio debuggers and CRT libraries (malloc and new apply)

When the program exits from only one location:

1. The following header files are required:

#define _CRTDBG_MAP_ALLOC#include#include

By including crtdbg.h, map malloc and free to_malloc_dbg and_free_dbg, respectively, for memory allocation and deallocation tracking.

The #define _CRTDBG_MAP_ALLOC statement is used to provide additional information, not absolutely necessary.

2. Before the program exits, use the following statement:

_CrtDumpMemoryLeaks();

This statement displays memory leak information in the output window.

test code

#define _CRTDBG_MAP_ALLOC#include#include#include#define NUM 10int main(){ char *test; test = (char*)malloc(NUM * sizeof(char)); _CrtDumpMemoryLeaks(); return 0;}

output result

When using_CRTDBG_MAP_ALLOC:

When_CRTDBG_MAP_ALLOC is not used:

If you add:

char *test;test = (char*)malloc(NUM * sizeof(char));

Replace with:

char* name = new char[10];

The same result will be obtained (memory location varies due to automatic allocation):

When the program exits from multiple locations:

1. Also contains the header file above

2. Include the following code at the beginning of every function that exits the program, including the main function:

_CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);

The program automatically calls_CrtDumpMemoryLeaks(); on exit.

test code

#define _CRTDBG_MAP_ALLOC#include#include#include#define NUM 10void test1();void test2();int main(){ _CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF); char *test; test = (char*)malloc(NUM * sizeof(char)); int a; puts("input a number"); scanf_s("%d", &a, sizeof(int)); if (a > 10) test1(); else if(a