C++检查内存泄露

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C++检查内存泄露

2013-01-12 09:27:24 我来说两句作者： iuhsihsow

我要投稿

说明，我使用的ide是vs2008

1. 工程设置为debug

内存泄露的检测一般在debug模式下进行

2.在需要检查内存泄露的cpp头部加上

[cpp]

#ifdef _DEBUG

#define _CRTDBG_MAP_ALLOC

#include <stdlib.h>

#include <crtdbg.h>

#define new new(_NORMAL_BLOCK, __FILE__, __LINE__)

#endif

3.代码中插入这么一句话

EnableMemLeakCheck();

[cpp]

inline void EnableMemLeakCheck()

{

_CrtSetDbgFlag(_CrtSetDbgFlag(_CRTDBG_REPORT_FLAG) | _CRTDBG_LEAK_CHECK_DF);

}

4.然后就可以在输出中看泄露情况了

举个例子，例子中我用newEx表示的上述宏定义中的new

[cpp]

int _tmain(int argc, _TCHAR* argv[])

{

EnableMemLeakCheck();

int num = 10;

byte **p = newEx byte *[num];

for (int i = 0; i < num; i ++)

{

Sleep(1);

*p = newEx byte[i];

}

long *pl = newEx long[100];

while(1)

{

Sleep(100);

}

return 0;

}

输出中显示的内容（debug下运行程序，然后点叉叉关闭程序）

memory leaks!

Dumping objects ->

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(101) : {124} normal block at 0x00295CB8, 400 bytes long.

Data: < > CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : {122} normal block at 0x00294C30, 9 bytes long.

Data: < > CD CD CD CD CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : {121} normal block at 0x00294BE8, 8 bytes long.

Data: < > CD CD CD CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : {120} normal block at 0x00299F88, 7 bytes long.

Data: < > CD CD CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : {119} normal block at 0x00299F40, 6 bytes long.

Data: < > CD CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : {118} normal block at 0x00299EF8, 5 bytes long.

Data: < > CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : {117} normal block at 0x00299EB8, 4 bytes long.

Data: < > CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : {116} normal block at 0x00299E78, 3 bytes long.

Data: < > CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : {115} normal block at 0x00299E38, 2 bytes long.

Data: < > CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : {114} normal block at 0x00299DF8, 1 bytes long.

Data: < > CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : {113} normal block at 0x00299DB8, 0 bytes long.

Data: <> 励p

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(88) : {112} normal block at 0x00299D50, 40 bytes long.

Data: <0L) > 30 4C 29 00 CD CD CD CD CD CD CD CD CD CD CD CD

Object dump complete.

有文件名和行号，先申请的后释放。

扩展：

实际上是使用了另外的new，在dbgnew.cpp中，列一个例子说明：

[cpp]

void *__CRTDECL operator new[](

size_t cb,

int nBlockUse,

const char * szFileName,

int nLine

)

_THROW1(_STD bad_alloc)

{

void *res = operator new(cb, nBlockUse, szFileName, nLine );

RTCCALLBACK(_RTC_Allocate_hook, (res, cb, 0));

return res;

}

注意，const char *szFileName可以使用__file__也可以使用自定义的类，经过重载为char*（感谢老马提供代码）

例如：

[cpp]

char new_index_recorder_file_name[1024 * 1024][256];

class new_index_recorder{

public:

new_index_recorder(char* file, int line) : file(file), line(line){

}

operator char*(){

static unsigned int index;

sprintf(new_index_recorder_file_name[index], "%s(%d) : %d ", file, line, index++);

return new_index_recorder_file_name[index];

}

private:

char* file;

int line;

};

当然，也可以用函数来返回char*指针

[cpp]

int g_count = 0;

class OperNew

{

public:

OperNew()

{

g_count ++;

pC = new char[20];

memset(pC, 0, 10);

sprintf(pC, "No.%d", g_count);

}

char* GetChar()

{

return pC;

}

private:

char * pC ;

};

这样就能返回自定义的内容了。本次的返回加上了一个构造时候的序号，当然也可以添加时间等。结果如下：

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(95) : 11 (95) : {123} normal block at 0x002B4C78, 400 bytes long.

Data: < > CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : 10 (92) : {122} normal block at 0x002B4C30, 9 bytes long.

Data: < > CD CD CD CD CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : 9 (92) : {121} normal block at 0x002B4BE8, 8 bytes long.

Data: < > CD CD CD CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : 8 (92) : {120} normal block at 0x002B9F88, 7 bytes long.

Data: < > CD CD CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : 7 (92) : {119} normal block at 0x002B9F40, 6 bytes long.

Data: < > CD CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : 6 (92) : {118} normal block at 0x002B9EF8, 5 bytes long.

Data: < > CD CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : 5 (92) : {117} normal block at 0x002B9EB8, 4 bytes long.

Data: < > CD CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : 4 (92) : {116} normal block at 0x002B9E78, 3 bytes long.

Data: < > CD CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : 3 (92) : {115} normal block at 0x002B9E38, 2 bytes long.

Data: < > CD CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : 2 (92) : {114} normal block at 0x002B9DF8, 1 bytes long.

Data: < > CD

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(92) : 1 (92) : {113} normal block at 0x002B9DB8, 0 bytes long.

Data: <> h鴌

e:\project\test\test_mem_leak\test_mem_leak\test_mem_leak.cpp(88) : 0 (88) : {112} normal block at 0x002B9D50, 40 bytes long.

Data: <0L+ > 30 4C 2B 00 CD CD CD CD CD CD CD CD CD CD CD CD

Object dump complete.

程序“[8796] test_MEM_LEAK.exe: 本机”已退出，返回值为 -1073741510 (0xc000013a)。

小提示：

将输出文件拷贝到UE中，然后查找泄露行号出现的次数，可以计算出泄露的数目。

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