What SIGNAL is emitted in Qt when pressing the "X" on the top right corner to terminate the Window?

Question

Which SIGNAL is emitted, when pressing the "X" in the top right corner of a Qt Window application?

I have a second QDialog widget beside my MainWindow in my Qt application. And I would like to intercept the press on the "X" in my second QDialog, how?

Answer 1

The QCloseEvent class contains parameters that describe a close event. Close events are sent to widgets that the user wants to close, usually by choosing "Close" from the window menu, or by clicking the X title bar button. They are also sent when you call QWidget::close() to close a widget programmatically.

To ignore it you can call ignore() method:

void YourDialog::closeEvent(QCloseEvent* iEvent)
{
  // ignore close event
  iEvent->ignore();
}

Answer 2

There is no signal for that, you need to reimplement QWidget::closeEvent() or install an event filter filtering for QCloseEvents.