Message-ID:	<35874A6E.35CACD01@post.comstar.ru>
Date:	Wed, 17 Jun 1998 08:47:42 +0400
From:	Dim Zegebart <zager AT post DOT comstar DOT ru>
Reply-To:	zager AT post DOT comstar DOT ru
Organization:	Comstar Ltd.
MIME-Version:	1.0
To:	jdh <neujdh AT ttuhsc DOT edu>
CC:	djgpp AT delorie DOT com
Subject:	Re: 16bit MS-Dos subsystem error
References:	<35869570 DOT 11493968 AT news DOT ttu DOT edu>

jdh wrote:

> I compiled a very large program using djgpp.  It compiled with no
> errors.  When I ran it, however, I got the following error message:
>
> "16bit MS-DOS Subsystem
>
> DOS prompt mlink
> The NTVDM CPU has encountered an illegal instruction
> cs:0000  ip:0000  op:54 01 fb 1b 8b      "
>
> I am clueless.  I compiled the program in the Windows NT DOS-prompt
> shell thing.  If I try to run the program(s) on a straight DOS
> machine,  I get a segmentation fault message.
>

The most possible reason is what you write into memory behind
allocated area. This may happens, for example, then you try to
strcpy(s,foo_string)
and strlen(foo_string) greater then number of bytes you allocated for s.

This is so-called runtime error and it couldn't be detected at compile
time.
So, even if compiler reports no error you can't be 100% sure in good
results.

--
____ ____
|   \   /   Dim Zegebart
____/____

Moscow Russia
WWW - http://www.geocities.com/siliconvalley/pines/7817
DZcomm - comm library for Allegro
Palantir - multitasking kernel for Allegro (based on PDMLWP)

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