processEvents processes only a single Event

The documentation for QApplication::processEvents() states that it processes events "... until there are no more events to process". However, with the glib-based event loop, this is not true. QEventDispatcherGlib::processEvents calls g_main_context_iteration only once and returns.

If this has been reported elsewhere, I was not able to find it. I really took some effort to dig up something, but these keywords appear in so many stack traces that it's impossible to google anything meaningful.

In a legacy app that I dare not touch any more than absolutely necessary I have something like this:

while (needsMoreWaiting()) {
  QApplication::processEvents();
  QThread::msleep(10);
}

This fails to keep up with handling mouse events, so moving the mouse excessively is a good way to send the application into blocked state for a few seconds. I need to use something like this now to get rid of this annyoing behavior:

while (needsMoreWaiting()) {
#if defined(Q_WS_X11)
  do {
    QApplication::processEvents();
  } while (QApplication::hasPendingEvents());
#else
  QApplication::processEvents();
#endif
  QThread::msleep(10);
}