Can I have a window that uses Qt::WA_DeleteOnClose and has a taskbar button at the same time?

Violet Giraffe

The question might sound weird, but bear with me.

In order for Qt::WA_DeleteOnClose to work the window (be it QWidget or QMainWindow; happens to be a QMainWindow in my case) must have a non-null parent.
In order for a window to have a taskbar button, at least on Windows, it must have a nullptr parent.

Quite a dilemma. Looks like I must implement deletion on close manually, but I would prefer a standard solution.

Chris Kawa

@Violet-Giraffe said:

In order for Qt::WA_DeleteOnClose to work the window must have a non-null parent.

Where did you get that idea from? That's not true at all.

Violet Giraffe

From my experiments. I'm certain of it, triple-checked.

Chris Kawa

I'm afraid you're gonna have to try it the fourth time then ;)
I suggest the following example for that:

#include <QApplication>
#include <QWidget>
#include <QDebug>

struct Widget : public QWidget {
    ~Widget() { qDebug() << "deleted!"; }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    auto w = new Widget();
    w->setAttribute(Qt::WA_DeleteOnClose);
    w->show();

    return a.exec();
}

Widget obviously has no parent and the output is "deleted!", as expected.

So you're doing something wrong. What problem are you trying to solve?

Violet Giraffe

Yep, this works. But my window still doesn't. Weird.

Chris Kawa

If you provide us with that window's code we might be able to pinpoint the problem.