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From: sa1z+@andrew.cmu.edu (Sudheer Apte)
Newsgroups: comp.lang.c
Subject: Re: &&**
Message-ID: <oav0Pq600WB6EO2Ilc@andrew.cmu.edu>
Date: 10 Sep 90 21:34:46 GMT
References: <1990Sep7.021321.18381@watmath.waterloo.edu> <1990Sep7.080855.24070@irisa.fr>,
	<0926@sheol.UUCP>
Organization: Civil Engineering, Carnegie Mellon, Pittsburgh, PA
Lines: 43
In-Reply-To: <0926@sheol.UUCP>

throopw@sheol.UUCP (Wayne Throop) writes:
> > From: ridoux@irisa.fr (Olivier Ridoux)
> > "what is the rational of the cc and gcc compilers (sun4) that 
> > makes them accept the following program...
> ...
> Now, on the other hand, I ran this program through microsoft C,
> feeling confident that it would be flagged as erronious.  To my
> surprise and amazement, it ran just as Olivier describes.  No
> slips, no drips, (and worst) no errors.
> 
> This is apparently a VERY common bug.  It shakes my faith in
> the competence of C implementors.  Unless I'm missing something
> quite major...???

You are quite correct.  GNU's gcc compiles it without a peep!
What is going on?  The standard seems quite clear about this,  but
I've never known gcc to misbehave before...

	Sudheer.
------------------
The program:

main()
{
char c = 'c' ;
char * pc = &c ;
char ** ppc = &pc ;

char d = 'd' ;
char * pd = &d ;
char ** ppd = &pd ;

  printf( "%c\n", *(*( &(&(*(*(ppc)))) )) );  /* 1 */
  printf( "%c\n", *(*( &(&(*(*(ppd)))) )) );  /* 2 */
  &(&(*(*(ppc)))) = ppd ;
  printf( "%c\n", *(*( &(&(*(*(ppc)))) )) );  /* 3 */

}



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