Xref: news2.mv.net comp.os.msdos.djgpp:7374
From: krecik AT ii DOT uni DOT wroc DOT pl (Grzegorz Nowakowski)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Debugging woes...
Date: 16 Aug 1996 11:52:00 GMT
Organization: Laboratoire de Recherche en Informatique, UPS/CNRS, Orsay,FRANCE
Lines: 40
Message-ID: <KRECIK.96Aug16135200@ii.uni.wroc.pl>
References: <199608122312 DOT JAA05520 AT gbrmpa DOT gov DOT au>
NNTP-Posting-Host: hp20.lri.fr
In-reply-to: Leath Muller's message of Mon, 12 Aug 1996 23:12:46 GMT
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

In article <199608122312 DOT JAA05520 AT gbrmpa DOT gov DOT au> Leath Muller <leathm AT gbrmpa DOT gov DOT au> writes:

> The problem: When I run the program normally, it dies with a seg fault...I
> have found the problem line using the traceback eip, and its:
> 	x = temp->next->x;
> in the subroutine which looks something like:
> 	while (temp->next != NULL)
> 	{
> 		...
> 		x = temp->next->x;
> 		...
> 	}
> I KNOW that the original structures pointer to next is originally assigned
> to NULL when it is added onto the end of a list (this is the only time
> it crashes), but upon execution of the program from the command line (win.exe)
> it crashes. Using printf of the temp->next value, I get some weird negative
> number like -24.
> 
> Anyway, I can't seem to debug it, because when I run the program under
> fsdb and single step, run etc the program, it runs fine!!! 
> 
> WHY?

Hmmm...  I can't give you any serious hint, but according to my
experience with linked structures there can be some sort of wild
pointer.  Once I had similar problem and it turned out that there was
improper pointer teleporting data across all memory.  Check also if
you recompiled *all* modules when you change structure definition.
And, finally, try to use gdb, IMHO it's more Borland-like than fsdb in
subject of debugging power. :)

-- 
						 Grzegorz Nowakowski
						<krecik AT ii DOT uni DOT wroc DOT pl>
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