From: "Dennis Katsonis" <dennisk AT netspace DOT net DOT au>
Newsgroups: comp.os.msdos.djgpp
Subject: allegro program crashes on exit
Date: Thu, 28 Dec 2000 08:20:43 +1100
Organization: Netspace Internet
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

I am writing a game using the Allegro graphics library ver 3.12 for DJGPP
The game works fine but for one problem.  It seems to cause the MS-DOS
prompt to crash occasionally when I exit the game with windows giving me a
dialog box about  an illegal operation.  The faulting component is given as
VMM(01)+0000FE7.
Most of the time the program exits fine, but if I start another prompt at a
later time, it may exit with this error.  If I recompile, it may then work
fine or may  not.  In DOS mode it seems to work fine.
Any help appreciated on what it may be, or how I can track the problem.  It
may be some sort of memory management problem, but I have looked through my
code.

The last few lines of code in the program are

 set_gfx_mode(GFX_TEXT,80,25,0,0);
        textptr +=__djgpp_conventional_base;
 __djgpp_nearptr_enable();
 memcpy(textptr,data[endscreen].dat,4000);
 __djgpp_nearptr_disable();

 gotoxy(0,23);

 return(0);

where textptr is previously set using the command
char unsigned*textptr = (byte*)0xB8000;