Debugger / message pump problems

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From: RBoggs (jollygreenfat_at_yahoo.com)
Date: 02/11/04 

Date: 10 Feb 2004 19:19:49 -0800

I'm having problems debugging a MFC app in eVC++ 4. The application is
essentially a container for several ActiveX controls with a
dialog-based graphical UI. Everything had been working well, until I
recently added several new dialogs & associated classes. Now when I
run the debug build of the application through the debugger, at a
certain point it always seems to lose the main dialog's message pump.
At this point there is a CEdit-derived object onscreen that has the
WM_ONCHAR message handled, and also a CButton-derived object w/ a
click handler. Previously these both behaved as expected; however, now
as soon as this screen displays, no messages are processed. The
OnChar, OnClick, and even events firing from the contained controls
are all unprocessed. The overall application is NOT hung, as trace
statements running in the background attest. The last thing done was
to set a flag telling the CEdit's KillFocus handler that it should not
allow focus to be taken away.

At this point the only way out is to kill the cemgr.exe process on the
debugging PC. Immediately upon doing this all the messages generated
on the CE platform get processed, and the debug application runs as
expected. eVC must be closed & restarted so that cemgr will fire back
up properly. The only symptom on the CE side is that when the same
screen is entered, now gwes.exe creates data aborts, but it does not
appear to affect the program's behavior.

I had of course originally thought that all my new code has some kind
of flaw in it. However, further trial & error indicates that simply
commenting out enough code in the application will allow things to run
as normal. It doesn't matter WHAT code, be it in older "established"
code or in the new code. It doesn't have to be code that's ever run up
to the point at which the "hang" occurs -- simply the amount being
compiled seems to be a factor. This is not a particularly large
application -- the release exe is only 600K, and memory usage w/ the
debug build is much less that what the system can handle (and only a
few K difference from a version that works properly). The ONLY time it
hangs is in a debug build running with the debugger - a release
(stand-alone or through debugger) always works, as does a debug
version run alone.

I'm clueless at this point at what could be the issue, or how I could
continue with proper debugging of the full application. Any
help/experience/thoughts would be GREATLY appreciated.

Richard Boggs
jollygreenfat@yahoo.com

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