while (QWindowSystemInterfacePrivate::windowSystemEventsQueued()) {
  QWindowSystemInterfacePrivate::WindowSystemEvent *event =
            (flags & QEventLoop::ExcludeUserInputEvents) ?
                QWindowSystemInterfacePrivate::getNonUserInputWindowSystemEvent() :
                QWindowSystemInterfacePrivate::getWindowSystemEvent();
        if (!event)
            break;
}

QWindowSystemInterfacePrivate::WindowSystemEvent *QWindowSystemInterfacePrivate::getNonUserInputWindowSystemEvent()
{
    return windowSystemEventQueue.takeFirstNonUserInputOrReturnNull();
}

        WindowSystemEvent *takeFirstNonUserInputOrReturnNull()
        {
            const QMutexLocker locker(&mutex);
            for (int i = 0; i < impl.size(); ++i)
                if (!(impl.at(i)->type & QWindowSystemInterfacePrivate::UserInputEvent))
                    return impl.takeAt(i);
            return 0;
        }