Re: #pragma STDC FENV_ACCESS ON

On Wed, Jul 17, 2024 at 4:01 PM Steve Kargl
<sgk@troutmask.apl.washington.edu> wrote:
>
> On Wed, Jul 17, 2024 at 01:30:39PM -0400, enh wrote:
> > i see lib/msun/src/e_sqrtl.c has `#pragma STDC FENV_ACCESS ON`, but
> > s_fma.c, s_fmaf.c, s_fmal.c, and s_nearbyint.c all use fesetround() or
> > fesetenv() too --- shouldn't they also have the pragma?
> >
> > (Android currently builds all of libm with that pragma, but (a) that
> > seems like a big hammer and (b) afaict upstream [you] don't, so this
> > is potentially causing problems^W^Wallowing the compiler to cause
> > problems for you?)
>
> Some of the compilers, which that are used to compile FreeBSD,
> do not support "#pragma STDC FENV_ACCESS ON".

that's why you have a line in the Makefile to quiet the warning :-)

(remember you _do_ have this #pragma in e_sqrtl.c already.)

> #include <stdio.h>
> #include <math.h>
>
> #pragma STDC FENV_ACCESS ON
>
> int
> main(void)
> {
>    double x = 1, y = 3;
>    printf ("x _ y = %la\n", x + y);
>    return 0;
> }
>
> % gcc13 -c -Wall a.c
> .c:5: warning: ignoring '#pragma STDC FENV_ACCESS' [-Wunknown-pragmas]
>     5 | #pragma STDC FENV_ACCESS ON
>       |
>
> --
> Steve
>