vld-2.2.3: http://vld.codeplex.com/releases/view/82311
方法一：
参考链接1: http://blog.csdn.net/dizuo/article/details/6030676
参考链接1和参考链接2说的是一个东西，不使用任何工具，自己写程序判断溢出位置。
方法二：
参考链接3和参考链接4是用VLD(Visual Leak Detector)来检测内存溢出，当然更加专业。
问题描述：
| 今天在QT_VP中简单地添加了内存泄露检测语句： _CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF ); 结果出来一大堆的内存泄露，着实吓了一跳，跟踪了一天，逐段派出，最后还是感觉没问题（还是比较自信代码质量的O(∩_∩)O哈哈~）。。。最后上网一查，在vs中，先是进行内存泄露报告，然后才卸载Qt的dll，释放申请的资源。所以才会出现这种情况。 |
系统环境：
windows7 + VS2008;
方法一：
操作方法与参考链接1做法一致，如下：
标志内存检测报告：setdebugnew.h（注意，只有在cpp中添加setdebugnew.h，而且有new操作的那些函数或者类被调用，才会进行内存泄露跟踪）
|
#ifndef SET_DEBUG_NEW_H
#define SET_DEBUG_NEW_H
#ifdef _DEBUG
#define DEBUG_CLIENTBLOCK new( _CLIENT_BLOCK, __FILE__, __LINE__)
#else
#define DEBUG_CLIENTBLOCK
#endif
#define _CRTDBG_MAP_ALLOC
#include <crtdbg.h>
#ifdef _DEBUG
#define new DEBUG_CLIENTBLOCK
#endif
#endif // end SET_DEBUG_NEW_H
|
在需要检测的cpp文件中包含setdebugnew.h头文件
test_memoryleak.cpp
|
#include "test_memoryleak.h"
#include <QtGui>
#include "setdebugnew.h"
test_memoryLeak::test_memoryLeak(QWidget *parent, Qt::WFlags flags)
: QWidget(parent, flags)
{
btn1 = new QPushButton("test1", this);
btn2 = new QPushButton("close", this);
QWidget *memLeak_test = new QWidget;
connect(btn2, SIGNAL(clicked()), this, SLOT(close()));
QHBoxLayout *layout = new QHBoxLayout;
layout->addWidget(btn1);
layout->addWidget(btn2);
setLayout(layout);
}
test_memoryLeak::~test_memoryLeak()
{
}
|
main.cpp(在主函数入口处设置_CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );)
|
#include "test_memoryleak.h"
#include <QtGui/QApplication>
#include "setdebugnew.h"
int main(int argc, char *argv[])
{
#ifdef _DEBUG
_CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );
#endif
int *i = new int;
QApplication a(argc, argv);
test_memoryLeak w;
w.show();
return a.exec();
}
|
启动调试，在程序运行结束后，查看“输出”项中的内容
|
{1220} normal block at 0x016605F8, 552 bytes long.
Data: < f > 83 00 00 00 83 00 00 00 08 06 66 01 CD CD CD CD
{1215} normal block at 0x01660398, 292 bytes long.
Data: < eH f x=g> 94 85 A2 65 48 03 66 01 00 00 00 00 C4 78 3D 67
. est_memoryleak.cpp(12) : {1214} client block at 0x01660348, subtype 0, 20 bytes long.
.
.
.
{289} normal block at 0x01388960, 56 bytes long.
Data: < 8 > 03 00 00 00 88 8A 38 01 00 CD CD CD 00 00 00 00
.main.cpp(12) : {285} client block at 0x013872B0, subtype 0, 4 bytes long.
Data: < > CD CD CD CD
Object dump complete.
|
黑体加粗部分的才是程序真正溢出的地方。
方法二：
使用VLD检测内存溢出，VLD下载地址： http://vld.codeplex.com/releases/view/82311（2.2.3版只支持VS2008/2010
）
安装过程会弹出如下对话框，
新版解决了path问题，所以我们无需做过多的设置。
安装完成后，还需要对VS的编译路径进行设置，
在“工具”->“选项”->”项目和解决方案“->"VC++目录" 添加VLD的”包含文件“路径和”库文件“路径，如下如所示：
注意：参考链接4提到了，在win7中需要拷贝dbghelp.dll和vdl_x86.dll到system32目录，而我在配置的时候并不需要这么做。
在main.cpp中包含vld.h头文件即可，如下：
|
#include "test_memoryleak.h"
#include <QtGui/QApplication>
#ifdef _DEBUG
#include "vld.h"
#endif
#include "setdebugnew.h"
int main(int argc, char *argv[])
{
#ifdef _DEBUG
_CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );
#endif
int *i = new int;
QApplication a(argc, argv);
test_memoryLeak w;
w.show();
return a.exec();
}
|
启动调试，在程序运行结束后，查看“输出”项中的内容
|
WARNING: Visual Leak Detector detected memory leaks!
---------- Block 1 at 0x007F72B0: 4 bytes ----------
Call Stack:
c:usersajaxhedesktopprogramqtpractice est_memoryleak est_memoryleakmain.cpp (17): test_memoryLeak.exe!main + 0x10 bytes
C:Qt4.7.4srcwinmainqtmain_win.cpp (131): test_memoryLeak.exe!WinMain + 0x12 bytes
f:ddvctoolscrt_bldself_x86crtsrccrtexe.c (578): test_memoryLeak.exe!__tmainCRTStartup + 0x35 bytes
f:ddvctoolscrt_bldself_x86crtsrccrtexe.c (403): test_memoryLeak.exe!WinMainCRTStartup
0x76B9ED6C (File and line number not available): kernel32.dll!BaseThreadInitThunk + 0x12 bytes
0x77D1377B (File and line number not available): ntdll.dll!RtlInitializeExceptionChain + 0xEF bytes
0x77D1374E (File and line number not available): ntdll.dll!RtlInitializeExceptionChain + 0xC2 bytes
Data:
CD CD CD CD ........ ........
---------- Block 4 at 0x00CA0348: 20 bytes ----------
Call Stack:
c:usersajaxhedesktopprogramqtpractice est_memoryleak est_memoryleak est_memoryleak.cpp (12): test_memoryLeak.exe!test_memoryLeak::test_memoryLeak
+ 0x10 bytes
c:usersajaxhedesktopprogramqtpractice est_memoryleak est_memoryleakmain.cpp (20): test_memoryLeak.exe!main + 0x17 bytes
C:Qt4.7.4srcwinmainqtmain_win.cpp (131): test_memoryLeak.exe!WinMain + 0x12 bytes
f:ddvctoolscrt_bldself_x86crtsrccrtexe.c (578): test_memoryLeak.exe!__tmainCRTStartup + 0x35 bytes
f:ddvctoolscrt_bldself_x86crtsrccrtexe.c (403): test_memoryLeak.exe!WinMainCRTStartup
0x76B9ED6C (File and line number not available): kernel32.dll!BaseThreadInitThunk + 0x12 bytes
0x77D1377B (File and line number not available): ntdll.dll!RtlInitializeExceptionChain + 0xEF bytes
0x77D1374E (File and line number not available): ntdll.dll!RtlInitializeExceptionChain + 0xC2 bytes
Data:
04 7C FB 00 98 03 CA 00 E0 7B FB 00 00 00 CD CD .|...... .{......
50 04 CA 00 P....... ........
Visual Leak Detector detected 2 memory leaks (96 bytes).
Largest number used: 260 bytes.
Total allocations: 260 bytes.
Visual Leak Detector is now exiting.
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溢出位置与预期一致！