QT application crashes on startup (c++ windows)

Question

I have the source code f a qt application which was written by somebody else who is not with my company anymore.

I managed to compile the code using qt 4.8.4. I found that original version used qt 4.7.3.

When I run application it crashes just after start-up inside one of the qt DLL.

I am developing on windows7 x64, but target is x86. I am using VS 2012 and compiled qt using VS 2012.

Do I need to set anything environment variable for QT to work properly?

Do I need to install any other software (such as opengl or any other library that qt relays on them)?

Edit 1

The stack after crashing is:

QtOpenGLd4.dll!QGLContextPrivate::extensionFuncs(const QGLContext * ctx) Line 467   C++
    QtOpenGLd4.dll!qt_resolve_glsl_extensions(QGLContext * ctx) Line 257    C++
    QtOpenGLd4.dll!QGLShaderPrivate::create() Line 227  C++
    QtOpenGLd4.dll!QGLShader::QGLShader(QFlags<enum QGLShader::ShaderTypeBit> type, const QGLContext * context, QObject * parent) Line 342  C++
    QtOpenGLd4.dll!QGLEngineSharedShaders::QGLEngineSharedShaders(const QGLContext * context) Line 191  C++
    QtOpenGLd4.dll!QGLContextGroupResource<QGLEngineSharedShaders>::value(const QGLContext * context) Line 777  C++
    QtOpenGLd4.dll!QGLShaderStorage::shadersForThread(const QGLContext * context) Line 63   C++
    QtOpenGLd4.dll!QGLEngineSharedShaders::shadersForContext(const QGLContext * context) Line 74    C++
    QtOpenGLd4.dll!QGLEngineShaderManager::QGLEngineShaderManager(QGLContext * context) Line 467    C++
    QtOpenGLd4.dll!QGL2PaintEngineEx::begin(QPaintDevice * pdev) Line 2150  C++
    QtGuid4.dll!QPainter::begin(QPaintDevice * pd) Line 1881    C++
    QtGuid4.dll!QPainter::QPainter(QPaintDevice * pd) Line 1508 C++
    myapp.exe!SViewer::paintEvent(QPaintEvent * __formal) Line 187  C++
    QtGuid4.dll!QWidget::event(QEvent * event) Line 8533    C++
    QtOpenGLd4.dll!QGLWidget::event(QEvent * e) Line 4408   C++
    QtGuid4.dll!QApplicationPrivate::notify_helper(QObject * receiver, QEvent * e) Line 4562    C++
    QtGuid4.dll!QApplication::notify(QObject * receiver, QEvent * e) Line 4527  C++
    QtCored4.dll!QCoreApplication::notifyInternal(QObject * receiver, QEvent * event) Line 946  C++
    QtCored4.dll!QCoreApplication::sendSpontaneousEvent(QObject * receiver, QEvent * event) Line 234    C++
    QtGuid4.dll!QWidgetPrivate::drawWidget(QPaintDevice * pdev, const QRegion & rgn, const QPoint & offset, int flags, QPainter * sharedPainter, QWidgetBackingStore * backingStore) Line 5598  C++
    QtGuid4.dll!QWidgetPrivate::repaint_sys(const QRegion & rgn) Line 1659  C++
    QtGuid4.dll!QWidgetPrivate::syncBackingStore() Line 1894    C++
    QtGuid4.dll!QWidget::event(QEvent * event) Line 8680    C++
    QtOpenGLd4.dll!QGLWidget::event(QEvent * e) Line 4408   C++
    QtGuid4.dll!QApplicationPrivate::notify_helper(QObject * receiver, QEvent * e) Line 4562    C++
    QtGuid4.dll!QApplication::notify(QObject * receiver, QEvent * e) Line 4527  C++
    QtCored4.dll!QCoreApplication::notifyInternal(QObject * receiver, QEvent * event) Line 946  C++
    QtCored4.dll!QCoreApplication::sendEvent(QObject * receiver, QEvent * event) Line 231   C++
    QtCored4.dll!QCoreApplicationPrivate::sendPostedEvents(QObject * receiver, int event_type, QThreadData * data) Line 1570    C++
    QtCored4.dll!qt_internal_proc(HWND__ * hwnd, unsigned int message, unsigned int wp, long lp) Line 496   C++
    user32.dll!75ce62fa()   Unknown
    [Frames below may be incorrect and/or missing, no symbols loaded for user32.dll]    
    user32.dll!75ce6d3a()   Unknown
    user32.dll!75ce6ce9()   Unknown
    user32.dll!75ce77c4()   Unknown
    user32.dll!75ce788a()   Unknown
    QtCored4.dll!QEventDispatcherWin32::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 810    C++
    QtGuid4.dll!QGuiEventDispatcherWin32::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 1204 C++
    QtCored4.dll!QEventLoop::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 150   C++
    QtCored4.dll!QEventLoop::exec(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 204    C++
    QtGuid4.dll!QDialog::exec() Line 555    C++
    myapp.exe!MainWindow::actionWelcomeDialog() Line 1078   C++
    myapp.exe!MainWindow::qt_static_metacall(QObject * _o, QMetaObject::Call _c, int _id, void * * _a) Line 92  C++
    QtCored4.dll!QMetaCallEvent::placeMetaCall(QObject * object) Line 524   C++
    QtCored4.dll!QObject::event(QEvent * e) Line 1194   C++
    QtGuid4.dll!QWidget::event(QEvent * event) Line 8845    C++
    QtGuid4.dll!QMainWindow::event(QEvent * event) Line 1479    C++
    QtGuid4.dll!QApplicationPrivate::notify_helper(QObject * receiver, QEvent * e) Line 4562    C++
    QtGuid4.dll!QApplication::notify(QObject * receiver, QEvent * e) Line 4527  C++
    QtCored4.dll!QCoreApplication::notifyInternal(QObject * receiver, QEvent * event) Line 946  C++
    QtCored4.dll!QCoreApplication::sendEvent(QObject * receiver, QEvent * event) Line 231   C++
    QtCored4.dll!QCoreApplicationPrivate::sendPostedEvents(QObject * receiver, int event_type, QThreadData * data) Line 1570    C++
    QtCored4.dll!qt_internal_proc(HWND__ * hwnd, unsigned int message, unsigned int wp, long lp) Line 496   C++
    user32.dll!75ce62fa()   Unknown
    user32.dll!75ce6d3a()   Unknown
    user32.dll!75ce6ce9()   Unknown
    user32.dll!75ce77c4()   Unknown
    user32.dll!75ce788a()   Unknown
    QtCored4.dll!QEventDispatcherWin32::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 810    C++
    QtGuid4.dll!QGuiEventDispatcherWin32::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 1204 C++
    QtCored4.dll!QEventLoop::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 150   C++
    QtCored4.dll!QEventLoop::exec(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 204    C++
    QtCored4.dll!QCoreApplication::exec() Line 1218 C++
    QtGuid4.dll!QApplication::exec() Line 3824  C++
    myapp.exe!main(int argc, char * * argv) Line 26 C++
    myapp.exe!WinMain(HINSTANCE__ * instance, HINSTANCE__ * prevInstance, char * __formal, int cmdShow) Line 131    C++
    myapp.exe!__tmainCRTStartup() Line 528  C
    myapp.exe!WinMainCRTStartup() Line 377  C
    kernel32.dll!758333aa() Unknown
    ntdll.dll!77d59ef2()    Unknown
    ntdll.dll!77d59ec5()    Unknown

Answer 1

I had the same problem with my own QT-Application using Qt 4.8.3 with OpenGL.

I found out that the crash is due to the using OpenGL paint engine. The engine type should automatically be set to OnegGL2 if the OpenGL driver reports that it supports OpenGL 2.0. This seems to be failing in my case.

To fix the problem I set the OpenGL preferred paint engine by adding the following code before constructing my QT-Application:

QGL::setPreferredPaintEngine(QPaintEngine::OpenGL);

Answer 2

Okay... here is your laundry list:

Make sure that you are building with the MSVS compiler, and compiling for win32.

If your application is surrounded by dll's built for mingw, or win64, you may have just entered "DLL he**". Make sure that you don't have any dll's sitting right next to your application's exe, or in the working directory (probably your folder that your source is in).

http://msdn.microsoft.com/en-us/library/windows/desktop/ms682586(v=vs.85).aspx#search_order_for_desktop_applications

Now go and check your system and user environment variables. Make sure that there isn't a listing for some Qt folder that you aren't building for.

Also go and make sure that Qt Creator or Visual Studio is pointing that the version of Qt you are building for.

Do a build clean on your project, and rebuild the whole thing. Be sure to read the "Compile Output" and "Build Output" folders.

Try building and running your program in debug. Then also try building and running your program in release. Make note of the application output, and the compile output.

If you are still crashing on startup, go and start putting in debug statements throughout your code to see where it is dying, or break points when you are running you debug version in debug mode. For example: qDebug() << Q_FUNC_INFO; at the top of your main function.

Also when it crashes, make note of the return code. Searching the return code in Google can also tell you a lot about what is going on.

Also check the paths that your program relies on.

Go and check your .pro file for any dependencies that you weren't aware of.

And beyond that you will probably need to give more info to get more help from me. :)

Hope that helps.