Segfaults when DeleteOnClose window attribute is set

[sunil.thaha]

Hi guys,

I am using Qt 4.2 on Cent OS ( 64 Bit )

I wrote a simple program for demonstration purpose.
Here is How the program works.

There are two Classes - MainDialog, NewDialog

In the main I create two dialogs, that is it .
Here is my main

#include <QApplication>
#include <QDialog>
#include "MainDialog.h"
#include "NewDialog.h"
 
int main( int argc, char *argv[] ){
    QApplication app( argc, argv );
 
    NewDialog newDialog;
    newDialog.show();
 
    MainDialog mainDialog;
    mainDialog.show();
 
    return app.exec();
}

#include <QApplication>
#include <QDialog>
#include "MainDialog.h"
#include "NewDialog.h"

int main( int argc, char *argv[] ){
    QApplication app( argc, argv );
    
    NewDialog newDialog;
    newDialog.show();
    
    MainDialog mainDialog;
    mainDialog.show();
    
    return app.exec();
}

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When I set the WindowAttribute of the MainDialog to WA_DeletOnClose.
I get a segfault when both the windows are closed.

Here is the code of the MainDialog.cpp

#include <QtDebug>
#include "NewDialog.h"
 
#include "MainDialog.h"
 
MainDialog::MainDialog( QWidget *parent )
        :QDialog( parent ) {
    setupUi( this );
    setAttribute( Qt::WA_DeleteOnClose );     // Adding this give segfaults 
 
    newDlg =0;
    qDebug()<< __FILE__ << " [" << __LINE__ << "]" << __FUNCTION__ << "() : ";
    connect( showDialogButton, SIGNAL(clicked()), this, SLOT(showDialog()) );
}
 
MainDialog::~MainDialog(){
}
 
void MainDialog::showDialog(){
    qDebug()<< __FILE__ << " [" << __LINE__ << "]" << __FUNCTION__ << "() : ";
    if( ! newDlg   ){
        newDlg = new NewDialog( this );
    }
    newDlg->show();
}

#include <QtDebug>
#include "NewDialog.h"

#include "MainDialog.h"

MainDialog::MainDialog( QWidget *parent )
        :QDialog( parent ) {
    setupUi( this );
    setAttribute( Qt::WA_DeleteOnClose );     // Adding this give segfaults 

    newDlg =0;
    qDebug()<< __FILE__ << " [" << __LINE__ << "]" << __FUNCTION__ << "() : ";
    connect( showDialogButton, SIGNAL(clicked()), this, SLOT(showDialog()) );
}

MainDialog::~MainDialog(){
}

void MainDialog::showDialog(){
    qDebug()<< __FILE__ << " [" << __LINE__ << "]" << __FUNCTION__ << "() : ";
    if( ! newDlg   ){
        newDlg = new NewDialog( this );
    }
    newDlg->show();
}

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PFA source of the program.
Am I missing something ?

[jpn]

You are allocating the widgets on the stack in main(), so the objects get destructed two times; 1) upon close 2) after going out of scope.

In other words, you must not set the Qt::WA_DeleteOnClose attribute for a widget allocated on stack.