X event loop

I need some advice from people who understand X. I am trying to debug a problem with the C-g detection in xemacs. The main part of this is in x_check_for_quit_char() which does the following: ------------------------------------------------------------ XtAppPending (Xt_app_con); XEventsQueued (display, QueuedAfterReading); queued = XCheckIfEvent (display, &event, quit_char_predicate, (char *) &critical_quit); ------------------------------------------------------------ To be able to interrupt system calls (like a hung connect()) with C-g the above is called _once_ from a SIGALARM signal handler. The problem is that XCheckIfEvent() doesn't seem to find all events. For example if I run all this from a debugger then what I see is that XCheckIfEvent() checks two events, but if I then immediately call XCheckIfEvent() again there is suddenly another event in the queue. If I call it once more then there are four (in my example finally including the C-g). I assume the idea of the XtAppPending() and XEventsQueued() calls was to avoid exactly this situation by making sure that all events are available in the queue. Obviously this doesn't work. Can anybody shed some light on this? Is there any way to make sure we really check all events? Gunnar P.S.: In case this is relevant: before all this we called fcntl (filedesc, F_SETFL, fcntl (filedesc, F_GETFL, 0) & ~FASYNC);