From:	"John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: problems running a prog.
Date:	Tue, 12 Nov 1996 18:43:57 -0800
Organization:	Three pounds of chaos and a pinch of salt
Lines:	32
Message-ID:	<328935ED.100C@cs.com>
References:	<9611121155 DOT AA07869 AT emma DOT ruc DOT dk>
Reply-To:	fighteer AT cs DOT com
NNTP-Posting-Host:	ppp108.cs.com
Mime-Version:	1.0
To:	Ole Winther <owsim AT ruc DOT dk>
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Ole Winther wrote:
> 
> I have a gcc compiled progr., when running it I got the error message
> "segment violation at pointer ... ", can anybody explain what that means and
> what course such errors? (the progr. runs when compiled with BC).

Your program is most likely attempting to dereference a NULL pointer. 
The cwsdpmi DPMI host that comes with DJGPP catches illegal
dereferences, but Borland's DPMI does not; nor does Windows.  This is a
definite bug in your program; you should fix it or run the risk of
crashing your computer.

Try running your program under a debugger like gdb, which will let you
see exactly where in your program the NULL pointer occurred.  For a
simpler technique, make sure the stack frame traceback (all that
hexadecimal garbage you get when you crash) is still on the screen, and
run 'symify <progname>', where <progname> is the name of your program. 
Assuming that you didn't strip the executable when you compiled, this
will show you the file and line number of the crash.

For more information, I suggest you download and read the DJGPP
Frequently Asked Questions list (v2/faq202b.zip from any SimTel site). 
It contains detailed and invaluable information on debugging program
errors.

-- 
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| John M. Aldrich, aka Fighteer I  |        fighteer AT cs DOT com         |
|    *  Proud user of DJGPP!  *    |   http://www.cs.com/fighteer   |
|    ObJoke:  If Bill Gates were a robber, not only would he        |
|     shoot you, but he'd send you a bill for the bullets.          |
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