[Bug-gsl] Re: Bug-gsl GSL on Solaris problems

[Brian Gough]

At Tue, 30 Oct 2007 14:02:14 +0100 (CET),
Richard Guenther wrote:
> 
> 
> This also occurs on linux with GCC 4.3 and the problem is likely that
> the overflow check in
> 
> void
> FUNCTION (my, initialize) (TYPE (gsl_vector) * v)
> {
>   size_t i;
>   ATOMIC k = 0, kk;
> 
>   /* Must be sorted initially */
> 
>   for (i = 0; i < v->size; i++)
>     {
>       kk = k;
>       k++;
>       if (k < kk)               /* prevent overflow */
>         k = kk;
>       FUNCTION (gsl_vector, set) (v, i, k);
>     }
> }
> 
> is broken for signed integral values.  As the ISO C standard defines
> signed integer overflow as invoking undefined behavior, the post-the-fact
> check is optimized away by compilers.  That this triggers only the signed
> char case is probably due to the sizes not causing overflow on other
> singed integral tests.

Thanks for the information, I'll fix that in the next release.

-- 
Brian Gough

GNU Scientific Library -
http://www.gnu.org/software/gsl/