When closing application Exception Triggered.

[SPlatten]

Is there anything I can do to help me trace what is causing an Exception Triggered dialog to be displayed when the application is shut down?

I've put a breakpoint in the class destructor Trainer and single stepped through it, everything looks ok and the exception seems to occur after exiting the exec() function, this is the main body:

int main(int arc, char *argv[])
{
    Trainer trainer(argc, argv);
    MainWindow w;
    w.show();
    return trainer.exec();
}

[mrjj]

Hi
Nothing is shown in the debugger call stack ?

[SPlatten]

@mrjj , yes the call stack, but there all go directly to assembler. The actual stop point is in:

RPCRT4!NDRCContextBinding:
    0x759ede63 <+0x0013>  cpp. sword ptr [eax+4], 0FEDCBA98h

[JonB]

@SPlatten
If we know nothing about Trainer, how would we answer?

Try replacing Trainer trainer with Trainer *trainer = new Trainer. Hopefully that avoids destructor being called. Does it still crash?

[mrjj]

Hi
Ok that is not super informative.

I think its maybe in the clean up phase something explodes.

You can try this
https://stackoverflow.com/questions/16735413/how-can-i-make-qtcreator-break-on-exceptions

It tells the debugger to stop where excpetion is thrown. maybe it can give a hint on whap happens.

Also I would try

// MainWindow w;
// w.show();

to see if its in trainer OR in the Mainwindow something happens.

Do you load or link any other DLLS etc ?

[SPlatten]

@JonB , I've just tried exactly that, its not calling the destructor now, but is still coming up with exactly the same exception dialog when the application is closed.

[SPlatten]

@mrjj said in When closing application Exception Triggered.:

https://stackoverflow.com/questions/16735413/how-can-i-make-qtcreator-break-on-exceptions

Tried that, no different.

[mrjj]

@SPlatten
Hi
And we are sure its not in MainWindow ?

[SPlatten]

@mrjj , I've just commented out everything in the MainWindow destructor, recompiled and run and its still doing the same.

[mrjj]

@SPlatten
Hi
ok. and you not having any members of QObject base in the class ?
I mean as non pointer in MainWindow.
Its sometimes possible to get double deletes that way.

[SPlatten]

@mrjj , at the moment the application is in very early stages for the MainWindow class contains just:

DataSets* mpDataSetsDlg;
Ui::MainWindow* mpui;

In the constructor:

MainWindow::MainWindow(QWidget* pParent) : QMainWindow(pParent),
                                           mpDataSetsDlg(nullptr),
                                           mpui(new Ui:MainWindow)
{
    mpui->setupUi(this);
    connect(mpui->btnDataSets, &QPushButton->clicked,
            this, &MainWindow::dataSetsBtnClicked);
}    

In the destructor:

void MainWindow::~MainWindow()
{
    if ( mpDataSetsDlg != nullptr )
    {
        delete mpDataSetsDlg;
        mpDataSetsDlg = nullptr;
    }
    delete mpui;
    mpui = nullptr;
}

[JonB]

@SPlatten
Remove all your #includes, other than what is required to get a minimal Qt program open a main window. It should be 10 lines long. No Trainer object No Trainer include files. Does it work?

If your program only crashes with Trainer and its include files, I still don't understand what we can say since we don't even know what it is.

[SPlatten]

@JonB , I modified main.cpp to:

#include <QApplication> //Add this
#include "main window.h"
//#include "trainer.h"

int main(int argc, char* argv[])
{
    //Trainer trainer(argc, argv);
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
    //return trainer.exec();
}

Rebuilt and it does exactly the same, crash location is in exactly the same place.

[J.Hilk]

@SPlatten well, in the stack trace, what's the first entry, thats from your code ?

you know that you can step back, when you're in assembler code right?

[JonB]

@SPlatten
Remove #include "main window.h" and replace MainWindow w; by QMainWindow w; (with presumably #include <QMainWindow>).

If that does not work, since it is the minimal Qt application what has changed for you since you last successfully built/ran any Qt GUI program?

[SPlatten]

@JonB , to be honest, it could be the build of the laptop, its an older version of Qt:

Qt Creator 4.4.1
Based on Qt 5.9.2 (MSVC 2015, 32 bit)

I have no control over the laptop or the version of Qt being used, this is supplied by the company I am contracted to.

[SPlatten]

@J-Hilk , I've expanded the stack trace and there is no call the traces back to my source, the first call is in Function: RtlGetAppContainerNamedObjectPath, File: ntdll

[J.Hilk]

@SPlatten thats unfortunate

since this is a basic and small project so far, can you share, the minimal example ?

that means probably only your custom MainWindow, so we can check ourselves, and check it against different Qt versions as well

[JonB]

@J-Hilk
That is why I suggested @SPlatten should use QMainWindow, not his own MainWindow, to test. If that still does not work (I'm not sure if he has answered that), then something is fundamentally with his Qt/environment. I would do that before examining anything about a custom MainWindow or header file.

[SPlatten]

@J-Hilk , in doing this, I decided to go one better. I did the following in Qt Creator:

1. Clicked on File top line menu
2. Selected New File or Project...
3. Selected Application and Qt Widgets Application
4. Clicked on the Choose... button
5. Entered test into Name: text box and clicked the Next button
6. Checked only Desktop Qt 5.9.2 MSVC2015 32bit in Kit Selection
7. Clicked Next button
8. Clicked Next button
9. Clicked Finish button
10. Right clicked project and selected Rebuild
11. Run application in debug mode and clicked the close widget in the MainWindow

Same thing happens, application stops and Exception Triggered dialog is displayed.