What am I doint wrong here?!?!

[Chris Croswhite]

ummm... I tried it with the int/&int and it works for -O2, however, when
using the other way, I have compiled this with -g and no problems, as
soon as I use -O(1,2,3) I run into the core dump, why do I get a core
dumb than and not with -g?

TIA,
Chris






On Sun, 2003-02-23 at 13:56, Oscar Fuentes wrote:
> Chris Croswhite <ccroswhite@get2chip.com> writes:
> 
> > gcc 3.2.2 on x86 (686):
> > What am I doing wrong here:
> > 
> > #include <math.h>
> > #include <stdio.h>
> > 
> > int main () {
> >   double val, num;
> >   int *exp;
> > 
> >   val = 5.0/2.0;
> > 
> >   num = frexp(val, exp);
> > 
> >   printf("num is %g\n", val);
> > 
> > return 1;
> > }
> > 
> > gcc -static -O2 foo.c -o foo
> > 
> > foo generates a dump.
> 
> You provided a pointer, but it points nowhere. 'frexp' uses that
> pointer to store a value on the address it points to. Either you use
> 
>    /* We allocate a piece of memory and set 'exp' to point there */
>    int *exp = (int*) malloc( sizeof(int) );
>  
>    val = 5.0/2.0;
>  
>    num = frexp(val, exp);
> 
> or simply
> 
>    /* Use a plain variable */
>    int exp;
>  
>    val = 5.0/2.0;
> 
>    /* We pass the address of 'exp' */ 
>    num = frexp(val, &exp);
> 
> HTH
-- 
Chris Croswhite <ccroswhite@get2chip.com>
Get2Chip, Inc.