[SOLVED] Simplest QApplication inheritance: segmentation fault on Linux only
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Hello,
I came across a strange behaviour. I inherit from QApplication in order to be able to intercept an application-wide esc-key.
Here I create the QApplication:@myQApplicationClass* myApp=new myQApplicationClass(qApp_argc,qApp_argv);@
and this is my 'myQApplicationClass':
@myQApplicationClass::myQApplicationClass(int argc ,char** argv) : QApplication(argc,argv)
{
}myQApplicationClass::~myQApplicationClass()
{
}bool myQApplicationClass::notify(QObject* object,QEvent* event)
{
if(event->type()==QEvent::KeyPress)
{
QKeyEvent* keyEvent=static_cast<QKeyEvent*>(event);
int key=keyEvent->key();
if (key==Qt::Key_Escape)
// do something
}
return(QApplication::notify(object,event));
};
@The first time I call a 'show' (e.g. on the splash screen or any other) the application crashes, but only on Linux (32 and 64bits). Windows works fine. When removing the 'notify' function, I get the same result. Only if I use myApp like follows, will it not crash on Linux:
@QApplication* myApp=new QApplication(qApp_argc,qApp_argv); // i.e. regular way to call it@
(with above line, the problems on Linux are resolved, but I don't have a global key press handler anymore).
Am I doing something wrong? Missing something? Or did I discover a bug?Thanks
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constructor signature is wrong, it should be:
@
myQApplicationClass(int & argc ,char** argv)
@
(pass argc as a reference instead of a copy)And btw. you can simply avoid subclassing QApplication at all and install an eventFilter on it and filter for the Esc-KeyEvent.
@
qApp->installEventFilter(object);
@
The event filter is called right after QApplication::notify() but still before any event gets delivered to a widget. -
A big big thank you Raven-worx! It's the '&' that I forgot that was the culprit!
