Bug in Microsoft C 5.1

[SMITHJ at ohstpy.mps.ohio-state.edu]

In article <1989Sep7.104322.1210 at gdt.bath.ac.uk>, mapmef at gdr.bath.ac.uk (M E Fletcher) writes:
> I've trimmed my program down substantially so there's for excuse at not
> looking at it now! I already know it's weird and horrible, but that's
> because it's from a larger program which has undergone major surgery.
> 
> 
> #include <stdio.h>
> static unsigned modulo[9]={0,0,0,0,0,0,0,0,0};
> main()
> {long *timeptr;
>  int i;
>  unsigned status;
>  i=0; while (i!=9)
>  {do {status=do_nothing(0,0,0);
>       printf("%d\n",i); }
>      while (0);
>   do {status=do_nothing(0,0,modulo[i]);}
>      while (status);
>   i++;
>  }
> }
> int do_nothing(a,b,c)
> int a,b,c;
> {return(0);}
> 
>  When I run this instead of printing out 0,1,2,3,4,5 etc. It prints out
> 0,1,1,1,1,1 etc. I think there is a bug in the compiler I am using :
> Micorsoft's 5.1 .  Can anyone confirm/deny/reproduce this?

I ran this program on a VAX/VMS using the latest version of VAX C and the
corresct sequence of numbers was printed out so that it does appear as tho'
you have located a bug in the MSC 5.1 compiler.

I suggest that you first try rewriting your program (if possible) so that it
looks more ANSI standard with regards to function calls:
	use 		function(type var,...)
			{
			/* ... */
			}
	instead of	function(var,...)
			type var,..
			{
			/* ... */
			}
I would also suggest changing the init/while constructs you use to 'for' loops.
While these may seem like silly suggestions you would be suprized how quickly
bugs disappear.

I have rewritten your fragment using my suggestions:

#include <stdio.h>

int main(void);
int do_nothing(int a,int b,int c);

static unsigned modulo[9]={0,0,0,0,0,0,0,0,0};

int main(void)
{
    long     *timeptr;
    int      i;
    unsigned status;
 
    for (i = 0; i != 9; ++i)
    {
	do 
	{
	    status = do_nothing(0,0,0);
      	    printf("%d\n",i); 
	} while (0);
  	do 
	{
	    status = do_nothing(0,0,modulo[i]);
	} while (status);
    }
}

int do_nothing(int a,int b,int c)
{
    return(0);
}
 
-- 
They have one big advantage over us: 
		*they* know where they're going.
Has your family tried 'em, Powdermilk?

/* Jeffery G. Smith, BS-RHIT (AKA Doc. Insomnia, WMHD-FM)       *
 *    The Ohio State University, Graduate Physics Program       *
 *        3193 Smith Lab, Columbus, OH 43210  (614) 292-5321    *
 *    smithj at ohstpy.mps.ohio-state.edu                          */