Firefox crush when try to show dialog from Qt GUI library (Linux ubuntu)

[barak]

Hello,

I have Qt GUI library which shows dialogs such as login. We use it with Firefox which calls the Qt library that should show a dialog. But at this point Firefox is closed with segmantation error.

I can use my Qt GUI library from non-Qt application by providing the QApplication inside the library and it works. I have the GTK 2.0 installed.

Thanks for any help you provide.

Barak

[tbscope]

That's way too few information to give a good answer.

So, install and/or rebuild the respective packages (firefox, qt, etc...) with debug information.
Then run it all through gdb and get a backtrace. Using the backtrace you can already see where the problem might be. If not, use the information to step through the program and look at the registers and variables.

A segmentation fault happens when you try to access memory you're not supposed to access (like in an uninitialized pointer)

[barak]

Thanks. How do I add debug information to my Qt library? Could it be related to the gtk-qt?

[barak]

OK it is crashing when I create the QApplication object:

QApplication * a = new QApplication(NULL,NULL);

QApplication * a = new QApplication(NULL,NULL);

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[wysota]

Passing it two nulls is probably what's causing the crash. You can't pass arbitrary values to objects and expect them to work.

[barak]

The full code is:

QApplication * a = 0;
if (!qApp){
 
	int argc = 1;
 
	char *argv[] = { "asePinDialog", NULL };
 
	a = new QApplication(argc,argv);
 
	//QApplication b(argc,argv);
 
	}
 
 
	m_iLastSlotId = aseData.slotID;
 
	ChangePin *pinDlg = new ChangePin(aseData);
 
	m_pOpenDialog = pinDlg;    
 
	pinDlg->exec();
    //pinDlg->show();
 
 
	bool bRet = (pinDlg->result() == QDialog::Accepted);
 
	delete pinDlg;
 
	m_pOpenDialog = NULL;
 
	m_iLastSlotId = 0;
 
	if(a){
 
		a->exit();
 
		delete a;
 
		a = 0;
 
	}
 
return bRet;

QApplication * a = 0;
if (!qApp){
        
	int argc = 1;
        
	char *argv[] = { "asePinDialog", NULL };
        
	a = new QApplication(argc,argv);
        
	//QApplication b(argc,argv);
    
	}

    
	m_iLastSlotId = aseData.slotID;
    
	ChangePin *pinDlg = new ChangePin(aseData);
    
	m_pOpenDialog = pinDlg;    
    
	pinDlg->exec();
    //pinDlg->show();

    
	bool bRet = (pinDlg->result() == QDialog::Accepted);
    
	delete pinDlg;
    
	m_pOpenDialog = NULL;
    
	m_iLastSlotId = 0;
    
	if(a){
        
		a->exit();
        
		delete a;
        
		a = 0;
    
	}
    
return bRet;

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