//! [0]
#ifdef Q_WS_X11
void qt_x11_wait_for_window_manager(QWidget *widget);
#endif

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    ...
    window.show();
#ifdef Q_WS_X11
    qt_x11_wait_for_window_manager(&window);
#endif
    ...
    return app.exec();
}
//! [0]