Embed Qt application into external window

Question

I have Qt application that I want to render onto a window provided by external application in Linux / X environment.

I know it is possible to start some applications and tell them to project themselves on one of my widgets: I get internally QWidget::winId() and start erxternal application with this as a parameter. I want to do reverse: start my Qt application with xid provided from elsewhere. I can't find how to do this direction.

Answer 1

Finally found out (explanation in comments):

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

    // create QWindow
    int hwnd = 35651603; // provided from other app, should be dynamic
    QWindow *nativeWindow = QWindow::fromWinId(hwnd);

    // Prepare something to show
    MainWindow w;
    
    // move displayed widget to desired location
    w.windowHandle()->setParent(nativeWindow);
    w.move(0, 0);

    // actually display. Must be done last
    w.show();

    return a.exec();
}