Visual Leak Detector 报告 qt 库泄漏

Posted 2023-02-17

【中文标题】Visual Leak Detector 报告 qt 库泄漏

【英文标题】：Visual Leak Detector reports qt library leaks

【发布时间】：2018-03-06 16:06:21

【问题描述】：

我创建了一个 Qt 4.7.4 程序，然后包含 vld 库来检测内存泄漏。结果是我得到了太多泄漏，大多数是 Qt 库泄漏，这很奇怪。有没有人遇到过这个问题？

memory_leak_report.txt是这样的：

Visual Leak Detector Version 2.5.1 installed.
    Outputting the report to C:\Users\kelgharb\Documents\Visual Studio 2010\Projects\Entreprise\EntrepriseCreator\memory_leak_report.txt WARNING: Visual Leak Detector detected memory leaks!
---------- Block 25 at 0x00E07E58: 20 bytes ----------   Leak Hash: 0x5688712A, Count: 1, Total 20 bytes   Call Stack (TID 1348):
    MSVCR100D.dll!operator new()
    c:\users\kelgharb\documents\visual studio 2010\projects\entreprise\entreprisecreator\generatedfiles\ui_createentreprise.h (50): EntrepriseCreator.exe!Ui_CreateEntrepriseClass::setupUi() + 0x7 bytes
    c:\users\kelgharb\documents\visual studio 2010\projects\entreprise\entreprisecreator\createentreprise.cpp (10): EntrepriseCreator.exe!CreateEntreprise::CreateEntreprise()
    c:\users\kelgharb\documents\visual studio 2010\projects\entreprise\entreprisecreator\entreprisecreator.cpp (45): EntrepriseCreator.exe!EntrepriseCreator::onTrigger_createEntreprise()
+ 0x31 bytes
    c:\users\kelgharb\documents\visual studio 2010\projects\entreprise\entreprisecreator\generatedfiles\debug\moc_entreprisecreator.cpp (82): EntrepriseCreator.exe!EntrepriseCreator::qt_metacall() + 0x8 bytes
    c:\qt\4.7.4\src\corelib\kernel\qmetaobject.cpp (238): QtCored4.dll!QMetaObject::metacall()
    c:\qt\4.7.4\src\corelib\kernel\qobject.cpp (3278): QtCored4.dll!QMetaObject::activate() + 0x27 bytes
    c:\qt\4.7.4\src\gui\tmp\moc\debug_shared\moc_qaction.cpp (263): QtGuid4.dll!QAction::triggered() + 0x15 bytes
    c:\qt\4.7.4\src\gui\kernel\qaction.cpp (1259): QtGuid4.dll!QAction::activate()
    c:\qt\4.7.4\src\gui\widgets\qmenu.cpp (1007): QtGuid4.dll!QMenuPrivate::activateCausedStack()
    c:\qt\4.7.4\src\gui\widgets\qmenu.cpp (1100): QtGuid4.dll!QMenuPrivate::activateAction()
    c:\qt\4.7.4\src\gui\widgets\qmenu.cpp (2297): QtGuid4.dll!QMenu::mouseReleaseEvent()
    c:\qt\4.7.4\src\gui\kernel\qwidget.cpp (8296): QtGuid4.dll!QWidget::event()
    c:\qt\4.7.4\src\gui\widgets\qmenu.cpp (2406): QtGuid4.dll!QMenu::event()
    c:\qt\4.7.4\src\gui\kernel\qapplication.cpp (4481): QtGuid4.dll!QApplicationPrivate::notify_helper() + 0x11 bytes
    c:\qt\4.7.4\src\gui\kernel\qapplication.cpp (4042): QtGuid4.dll!QApplication::notify() + 0x2F bytes
    c:\qt\4.7.4\src\corelib\kernel\qcoreapplication.cpp (787): QtCored4.dll!QCoreApplication::notifyInternal() + 0x15 bytes
    c:\qt\4.7.4\src\corelib\kernel\qcoreapplication.h (218): QtCored4.dll!QCoreApplication::sendSpontaneousEvent() + 0x38 bytes
    c:\qt\4.7.4\src\gui\kernel\qapplication.cpp (3139): QtGuid4.dll!QApplicationPrivate::sendMouseEvent() + 0xE bytes
    c:\qt\4.7.4\src\gui\kernel\qapplication_win.cpp (3234): QtGuid4.dll!QETWidget::translateMouseEvent() + 0x2A bytes
    c:\qt\4.7.4\src\gui\kernel\qapplication_win.cpp (1659): QtGuid4.dll!QtWndProc() + 0xC bytes
    USER32.dll!gapfnScSendMessage() + 0x332 bytes
    USER32.dll!GetThreadDesktop() + 0xD7 bytes
    USER32.dll!CharPrevW() + 0x138 bytes
    USER32.dll!DispatchMessageW() + 0xF bytes
    c:\qt\4.7.4\src\corelib\kernel\qeventdispatcher_win.cpp (810): QtCored4.dll!QEventDispatcherWin32::processEvents()
    c:\qt\4.7.4\src\gui\kernel\qapplication_win.cpp (1170): QtGuid4.dll!QGuiEventDispatcherWin32::processEvents() + 0x15 bytes
    c:\qt\4.7.4\src\corelib\kernel\qeventloop.cpp (150): QtCored4.dll!QEventLoop::processEvents()
    c:\qt\4.7.4\src\corelib\kernel\qeventloop.cpp (201): QtCored4.dll!QEventLoop::exec() + 0x2D bytes
    c:\qt\4.7.4\src\corelib\kernel\qcoreapplication.cpp (1064): QtCored4.dll!QCoreApplication::exec() + 0x15 bytes
    c:\qt\4.7.4\src\gui\kernel\qapplication.cpp (3756): QtGuid4.dll!QApplication::exec()
    c:\users\kelgharb\documents\visual studio 2010\projects\entreprise\entreprisecreator\main.cpp (12): EntrepriseCreator.exe!main() + 0x6 bytes
    c:\qt\4.7.4\src\winmain\qtmain_win.cpp (131): EntrepriseCreator.exe!WinMain() + 0x12 bytes
    f:\dd\vctools\crt_bld\self_x86\crt\src\crtexe.c (547): EntrepriseCreator.exe!__tmainCRTStartup() + 0x2C bytes
    f:\dd\vctools\crt_bld\self_x86\crt\src\crtexe.c (371): EntrepriseCreator.exe!WinMainCRTStartup()
    kernel32.dll!BaseThreadInitThunk() + 0x12 bytes
    ntdll.dll!RtlInitializeExceptionChain() + 0x63 bytes
    ntdll.dll!RtlInitializeExceptionChain() + 0x36 bytes   Data:
    D4 50 01 01    18 0A 92 02    AC 50 01 01    00 00 CD CD     .P...... .P......
    D0 0A 92 02                                                  ........ ........
---------- Block 22 at 0x02892950: 52 bytes ----------   Leak Hash: 0x04BB07FE, Count: 1, Total 52 bytes   Call Stack (TID 1348):
    MSVCR100D.dll!operator new()
    c:\users\kelgharb\documents\visual studio 2010\projects\entreprise\entreprisecreator\entreprisecreator.cpp (45): EntrepriseCreator.exe!EntrepriseCreator::onTrigger_createEntreprise()
+ 0x7 bytes
    c:\users\kelgharb\documents\visual studio 2010\projects\entreprise\entreprisecreator\generatedfiles\debug\moc_entreprisecreator.cpp (82): EntrepriseCreator.exe!EntrepriseCreator::qt_metacall() + 0x8 bytes
    c:\qt\4.7.4\src\corelib\kernel\qmetaobject.cpp (238): QtCored4.dll!QMetaObject::metacall()
    c:\qt\4.7.4\src\corelib\kernel\qobject.cpp (3278): QtCored4.dll!QMetaObject::activate() + 0x27 bytes
    c:\qt\4.7.4\src\gui\tmp\moc\debug_shared\moc_qaction.cpp (263): QtGuid4.dll!QAction::triggered() + 0x15 bytes
    c:\qt\4.7.4\src\gui\kernel\qaction.cpp (1259): QtGuid4.dll!QAction::activate()
    c:\qt\4.7.4\src\gui\widgets\qmenu.cpp (1007): QtGuid4.dll!QMenuPrivate::activateCausedStack()
    c:\qt\4.7.4\src\gui\widgets\qmenu.cpp (1100): QtGuid4.dll!QMenuPrivate::activateAction()
    c:\qt\4.7.4\src\gui\widgets\qmenu.cpp (2297): QtGuid4.dll!QMenu::mouseReleaseEvent()
    c:\qt\4.7.4\src\gui\kernel\qwidget.cpp (8296): QtGuid4.dll!QWidget::event()
    c:\qt\4.7.4\src\gui\widgets\qmenu.cpp (2406): QtGuid4.dll!QMenu::event()
    c:\qt\4.7.4\src\gui\kernel\qapplication.cpp (4481): QtGuid4.dll!QApplicationPrivate::notify_helper() + 0x11 bytes
    c:\qt\4.7.4\src\gui\kernel\qapplication.cpp (4042): QtGuid4.dll!QApplication::notify() + 0x2F bytes
    c:\qt\4.7.4\src\corelib\kernel\qcoreapplication.cpp (787): QtCored4.dll!QCoreApplication::notifyInternal() + 0x15 bytes
    c:\qt\4.7.4\src\corelib\kernel\qcoreapplication.h (218): QtCored4.dll!QCoreApplication::sendSpontaneousEvent() + 0x38 bytes
    c:\qt\4.7.4\src\gui\kernel\qapplication.cpp (3139): QtGuid4.dll!QApplicationPrivate::sendMouseEvent() + 0xE bytes
    c:\qt\4.7.4\src\gui\kernel\qapplication_win.cpp (3234): QtGuid4.dll!QETWidget::translateMouseEvent() + 0x2A bytes
    c:\qt\4.7.4\src\gui\kernel\qapplication_win.cpp (1659): QtGuid4.dll!QtWndProc() + 0xC bytes
    USER32.dll!gapfnScSendMessage() + 0x332 bytes

【问题讨论】：

Qt 中存在各种内存泄漏。如果没有浏览代码并修复它们，那么您对它们无能为力。考虑为 Qt 添加过滤器或异常，这样它就不会在您自己的代码中隐藏内存泄漏。

Khaled 为什么还在 Qt4.7 上，只是测试？它太旧了，现在您可以使用 Qt 5.10.1，并在 Qt Creator 4.5.1 中参考 Detecting Memory Leaks

@MohammadKanan 没错，我只是在测试一个程序。

【参考方案1】：

与 Qt 相关的内存泄漏是由于 QDialogs 造成的，我每次创建新的 QDialog 对象时都缺少一行 setAttribute(Qt::WA_DeleteOnClose)：

void EntrepriseCreator::onTrigger_createEntreprise()

    CreateEntreprise* entreprise = new CreateEntreprise();
    entreprise->setAttribute(Qt::WA_DeleteOnClose);
    QObject::connect(entreprise, SIGNAL(disable_actionEntreprise(bool)), this, SLOT(disable_actionEntreprise(bool)));
    entreprise->exec();