From:	"Tim Nicholson" <T DOT J DOT Nicholson AT btinternet DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Annoying error
Date:	Sat, 26 May 2001 16:19:15 +0100
Organization:	Skyforce avionics Limited
Lines:	62
Message-ID:	<9eohkl$j3k$1@neptunium.btinternet.com>
References:	<HnLP6.16992$iS2 DOT 597769 AT news DOT chello DOT at>
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

Hi,

if you type symify a.exe (where a.exe is your program name) on the command
prompt after your program crashes it will list the functions which were
called prior to the crash. This will point you to which function failed. You
can then use debugger in Rhide to trace into the failing function and find
the exact point of failure. It is probably being caused by the inadvertent
use of a NULL pointer or something along those lines. I bet, even when it
seems to work, it is not doing exactly what you intended it to!

Also, have a look in the FAQ, Eli has some great tips on tracking down this
sort of problem and making sense of the error messages produced when a DJGPP
program comes off the rails.

Tim

"Maverick" <vhd AT chello DOT at> wrote in message
news:HnLP6.16992$iS2 DOT 597769 AT news DOT chello DOT at...
> I just finished my first program with DJGPP, it does not much more than
> calculate a few entries in an array off two other arrays. It compiles and
> links without errors, however when I run the EXE-file, I get the following
:
>
> -------------------------------------------------------------
> Exiting due to signal SIGSEGV
> Page fault at eip = 000019d3, error = 0006
> eax = 00048018  ebx = 000084c3  ecx = 00000084
> edx = 00010f60  esi = 00000054  edi = 00043560
> ebp = 071efe30  esp = 071efdf8
> program=C:\U1\DEVELOP\COLORMAP\A.EXE
>
> cs:    sel = 01ef     base = 84c33000    limit = fffe2fff
> ds:    sel = 0217    base = 84c33000    limit = fffe2fff
> es:    sel = 0217    base = 84c33000    limit = fffe2fff
> fs:     sel = 0127    base = 00014d10    limit = 0000ffff
> gs:    sel = 0227    base = 00000000    limit = 0010ffff
> ss:    sel = 0217    base = 84c33000    limit = fffe2fff
> App stack : [071f0000..07170000]
> Exceptn stack : [000434bc..0004157c]
>
> Call frame traceback EIPs:
> 0x000019d3
> 0x00001da7
> 0x00001f42
> 0x00003342
>
> -------------------------------------------------------------
> And now for the funny thing. This error happens always when the EXE is
> executed from the DOS-Prompt of Win98SE-Dos Box. When I launch it from
RHIDE
> (started in Win98SE-Dos Box) it sometimes works just fine, and sometimes
> gives me out the same error as above. In DOS-Mode of Win98SE however the
> program works out just fine without any errors. Now I'm curious if
somebody
> can tell me what this error means and if somebody can find an explanation
> why it does work sometimes and sometimes not.
>
> Maverick
>
>

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