Message-ID: <3F1DACE5.3080903@student.kuleuven.ac.be>
Date: Tue, 22 Jul 2003 23:30:13 +0200
From: Peter Claessens <peter DOT claessens AT student DOT kuleuven DOT ac DOT be>
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To: djgpp AT delorie DOT com
Subject: Re: malloc/free blues
References: <3F156434 DOT 3000508 AT psy DOT kuleuven DOT ac DOT be>
In-Reply-To: <3F156434.3000508@psy.kuleuven.ac.be>
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Reply-To: peter DOT claessens AT psy DOT kuleuven DOT ac DOT be

My problem is finally solved now... I did the following:
I installed djdev 2.04, where malloc_debug and malloc_verify are 
implemented in the libc, recompiled with malloc debugging level to 4. I 
had to use some tricks to read the error output, because right after the 
abort due to the memory problem, I got in an infinite 'abort' loop 
somewhere in the allegro_exit function. It turned out that the 'fixpage' 
pointer (see first post, with the code) and the associated struct fields 
were always involved in these crashes.  Then I suddenly spotted the 
problem in my code. Normally I set a pointer to NULL after deleting its 
object, and I do the same for bitmap pointers after calling 
destroy_bitmap; I check pointers against being zero before trying to 
delete or destroy them. Forgetting to set the pointer to NULL after a 
destroy_bitmap one time was enough to cast this nightmare upon me. I 
added the line to do so, and behold.... my program doesn't crash. I 
deleted the malloc_dbug statement though, because of the errors I 
receive when shutting down the program. 
Conclusion: I lost a lot of time, but at least I learned a lot about 
debugging.
Many thanks to everyone who helped me sorting out this problem!

Cheers,
Peter.