On Mon, Mar 19, 2007 at 07:17:46PM -0700, Darrin Chandler wrote:
> On Mon, Mar 19, 2007 at 07:12:24PM -0300, Gustavo Rios wrote:
> > I am writing a very simple program but the output change for the c
> > variable value change every time i run it. What would it be my mistake
> > on the source? Did i forget some thing?
> >
> > #include <stdio.h>
> >
> > int
> > main(int argc, char **argv)
> > {
> > unsigned long long x, c;
> > unsigned *p;
> >
> > x = 1, x+= (unsigned long long)1 << 33 ;
> > p = (void *)&x;
> > c = p[0] * p[1];
> >
> > fprintf(stdout, "x:%llu\n", x);
> > fprintf(stdout, "0,1:%u,%u\n", p[0], p[1]);
> > fprintf(stdout, "c:%llu\n", c);
> >
> > return 0;
> > }
>
> I run this many times, with other stuff in between, and I always get:
>
> $ ./gustavo
> x:8589934593
> 0,1:1,2
> c:2
>
> Same values for everything, every time. Hmm.
Compile it with -O3. Then enjoy.
