Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!snorkelwacker!bloom-beacon!EXPO.LCS.MIT.EDU!rws
From: rws@EXPO.LCS.MIT.EDU (Bob Scheifler)
Newsgroups: comp.windows.x
Subject: Re: Browsing Event Queue
Message-ID: <9009132329.AA27408@expire.lcs.mit.edu>
Date: 13 Sep 90 23:29:50 GMT
References: <142429@sun.Eng.Sun.COM>
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 18

This seems like another of those frequently asked questions.  All it
takes is a little imagination.

    As far as I can tell there is no way to look for a certain
    type of event without blocking or removing it from the queue.

Use XCheckIfEvent.  Have your predicate *always* return False.  Maintain
the *real* boolean result (or whatever other result you want) in the
private data argument that you pass in.  If you're sensible, write a
nice wrapper function that hides this trick, so that the wrapper function
has a reasonable interface.  Call the function Xmu<something-or-other>,
and send it back to us. :-)

Call it ugly, call it a kludge, but it works and it's portable.  Yes,
it means you always walk all the way through the event queue, but the
queue shouldn't normally be that long, and quick return from your
predicate once you've found an event of interest shouldn't cost very
much.