From:	Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Q: Is it possible to use GDB debugger with Allegro?
Date:	Mon, 30 Dec 1996 19:40:13 +0000
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Distribution:	world
Message-ID:	<8PY8kpAdqByyEw3J@talula.demon.co.uk>
References:	<59snma$qju AT newton DOT pacific DOT net DOT sg>
NNTP-Posting-Host:	talula.demon.co.uk
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

>I tried to debug a program written using Allegro graphics library, but
>it doesn't work (my computer goes into a deep coma, and even
>Ctrl-Alt-Del doesn't help).

Really? It works better than that for me. When your program hits a
breakpoint you'll need to switch to text mode (type "system mode co80"),
but after doing that I can single-step through Allegro programs without
any problems. The problem comes when you want to resume execution -
there is no way to restore the screen state, and gdb also seems to
remove Allegro's keyboard and timer interrupt handlers, although I
haven't properly investigated this.

I'm surprised it dies so thouroughly: what versions of Allegro and gdb
are you using here? And what dpmi provider?

>Is there any way around it, or other debugger to use with Allegro?

It might be worth trying FSDB. Although I've never used it myself, I
believe it can handle VGA graphics modes. Ideally, of course, it would
be nice if someone could teach gdb about saving and restoring VESA
screen modes, but that isn't something I have time for myself...

/*
 *  Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
 *  Ghoti: 'gh' as in 'enough', 'o' as in 'women', and 'ti' as in 'nation'.
 */

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