From: Thomas Demmer <demmer AT LSTM DOT Ruhr-UNI-Bochum DOT De>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Runs in Win95, crashes in DOS.
Date: Tue, 30 Dec 1997 08:50:21 +0100
Organization: Lehrstuhl fuer Stroemungsmechanik
Lines: 47
Message-ID: <34A8A7BD.D0CC544E@LSTM.Ruhr-UNI-Bochum.De>
References: <34A89BEA DOT 141C714 AT bethany DOT edu>
NNTP-Posting-Host: bvb.lstm.ruhr-uni-bochum.de
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Precedence: bulk

pneyz wrote:
> 
> I have DJGPP installed correctly and everything, but a lot of my
> programs will only work in Win95, and not in pure DOS. These programs
> all make use of command line parameters, and that is where the problem
> is manifesting. I managed to narrow it down to the following:
> 
>    int main (int argc, char *argv[])
>    {
>     if (!strcmp(argv[1], "-h")) return 1;
>     else return 0;
>    }
> 
> That should test to see if argv[1] is "-h" and if it is, return 1, and
> if not, return 0. This works fine in Win95, but in DOS I get a error
> screen about SIGSENT (actually, I'm not too sure about what it says, as
> I can't reproduce it in Win95 right now). Any code before that executes
> fine, but it stops there. Any help will be much appreciated.
Better start switching to a slightly more defensive programming style.
If you call your program without arguments, argv[1] is a NULL pointer,
and there is only very little point in checking if INT 0 points
to memory location "-h".

The problem is that W95 is a really f*d up DPMI hosts that doesn't
catch those errors. Try 
    char foo[256];
    char *bar=NULL;
    strcpy(bar,"Hello");
    strcpy(foo,bar);
    puts(foo);

under W95 & CWSDPMI and go figure.

-- 
Ciao
Tom

*************************************************************
* Thomas Demmer                                             *
* Lehrstuhl fuer Stroemungsmechanik                         *
* Ruhr-Uni-Bochum                                           *
* Universitaetsstr. 150                                     *
* D-44780  Bochum                                           *
* Tel: +49 234 700 6434                                     *
* Fax: +49 234 709 4162                                     *
* http://www.lstm.ruhr-uni-bochum.de/~demmer                *
*************************************************************