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Mail Archives: djgpp/2001/01/28/22:52:57

From: Jason Green <news AT jgreen4 DOT fsnet DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Windows ME and DJGPP
Date: Mon, 29 Jan 2001 00:48:09 +0000
Organization: Customer of Energis Squared
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com

> > It compiles cleanly like this:
> > 
> > int main(void)
> > {
> >  char *p = 0;
> >  *p = 'X';
> >  
> >  return 0;
> > }

> > > And I do not think clean code can contain a line which can produce many
> > > errors that result in SIGSEGV but gives no hint about it.
> > 
> > Try stepping up the warnings you have enabled.  I don't think it's
> > possible for gcc to flag bugs like in the above example but it might
> > show up some other problem with your code.
> 
> Perhaps it can flag this one when optimizing.

Not when I tried, although lint might catch this.  

One reason gcc misses it may be that all-bits-zero pointer is valid on
some platforms (I think).  Feel free to suggest this to the gcc
maintainers though.

My point though was not regarding the example code.  I am merely
suggesting to up the warning level to something more extreme when
compiling the problem code, in order to see how clean it really is and
perhaps weed out a bug.  I should add that of course I don't know what
warnings you are using (and so what you mean by clean code) - maybe
you already did this.

I'm kinda loosing the thread here, are you saying you only get SIGSEGV
under Windows ME?  Did you try your program under real-mode DOS (from
boot floppy)?

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