Qt程序是不是会内存泄漏

pridesky

最近在Qt项目中发现,程序运行内存越来越大,然后使用_CrtDumpMemoryLeaks进行内存检查,发现很多泄漏提示,但是检查代码没发现问题.

于是使用VS2010 创建了一个Qt console程序,代码如下,

#include <QtCore/QCoreApplication>
#include <assert.h>
/************************************************************************/
#ifdef _DEBUG
#define _CRTDBG_MAP_ALLOC
#include <crtdbg.h>
#define DEBUG_CLIENTBLOCK new( _CLIENT_BLOCK, FILE, LINE)
#define new DEBUG_CLIENTBLOCK
static void Exit()
{
int i = _CrtDumpMemoryLeaks();
assert( i == 0);
}
#define CheckMemoryLeaks() {atexit(Exit);}

#else
#define DEBUG_CLIENTBLOCK
#define CheckMemoryLeaks() ；
#endif

/************************************************************************/
int main(int argc, char *argv[])
{
CheckMemoryLeaks();
QCoreApplication a(argc, argv);

return a.exec();
}

===============================================================================
输出信息如下:

Detected memory leaks!
Dumping objects ->
{176} normal block at 0x013A57F0, 12 bytes long.
Data: < L ]L ]> 00 00 00 00 4C CF 1C 5D 4C CF 1C 5D
{175} normal block at 0x013A57A8, 12 bytes long.
Data: < L ]L ]> 00 00 00 00 4C CF 1C 5D 4C CF 1C 5D
{174} normal block at 0x013A56F8, 112 bytes long.
Data: < ] V: L ]> 8C CB 1B 5D B0 56 3A 01 00 00 00 00 4C CF 1C 5D
{173} normal block at 0x013A56B0, 8 bytes long.
Data: < ] V: > 98 CB 1B 5D F8 56 3A 01
{172} normal block at 0x013A5670, 4 bytes long.
Data: <L ]> 4C CF 1C 5D
{171} normal block at 0x013A5620, 20 bytes long.
Data: <@ ]@ ]@ ]@ ]> 40 20 1C 5D 40 20 1C 5D 40 20 1C 5D 40 20 1C 5D
{170} normal block at 0x013A55E0, 4 bytes long.
Data: <@ ]> 40 20 1C 5D
{156} normal block at 0x013A5530, 16 bytes long.
Data: < > 01 CD CD CD 00 00 00 00 00 00 00 00 00 00 00 00
{155} normal block at 0x013A54F0, 4 bytes long.
Data: <0U: > 30 55 3A 01
{154} normal block at 0x013A5288, 552 bytes long.
Data: < R: > 83 00 00 00 83 00 00 00 98 52 3A 01 CD CD CD CD
{151} normal block at 0x013A50D8, 108 bytes long.
Data: < ] P: L ]> E8 B9 1B 5D 90 50 3A 01 00 00 00 00 4C CF 1C 5D
{150} normal block at 0x013A5090, 8 bytes long.
Data: < ] P: > A8 B9 1B 5D D8 50 3A 01
{149} normal block at 0x013A5018, 60 bytes long.
Data: < P: > 02 00 00 00 90 50 3A 01 FC 1B 00 00 00 CD CD CD
{145} normal block at 0x013A4E58, 32 bytes long.
Data: < > 01 00 00 00 04 00 00 00 00 00 00 00 01 00 00 00
{144} normal block at 0x013A4E08, 20 bytes long.
Data: < 4)] \5] \5]( 1]> BC 34 29 5D F0 5C 35 5D 90 5C 35 5D 28 82 31 5D
{143} normal block at 0x013A4DC8, 4 bytes long.
Data: <XN: > 58 4E 3A 01
{142} normal block at 0x013A4D78, 16 bytes long.
Data: < > 01 CD CD CD 00 00 00 00 00 00 00 00 00 00 00 00
{141} normal block at 0x013A4D38, 4 bytes long.
Data: <xM: > 78 4D 3A 01
Object dump complete.

是方法错误还是Qt本身的问题?坐等高手````

LJoker

你的工具是用于检测MFC的，QT有自己的垃圾回收机制，就是对象父子关系。

henryxuv

QT的回收机制在哪里？？我不知道你在哪里看到的回收机制，反正我是没有看到过。
QT只是一个庞大的C++类库，它本身没有对C++有任何的改变，我是说new,delete,他自然也不会有回收机制，你依然要在你程序里去控制开辟出来的内存。

jiangcaiyang

一楼的意思是Qt在进入QObject的析构函数的时候，他会释放掉QObject内部所持有所有孩子的实例。这一点要格外注意。
你的项目大，所以在设计的时候必须考虑：在事件循环的时候有没有用到new操作符。要么可以重载全局的new操作符，输出实例的个数。