At Sat, 15 Oct 2011 19:35:40 -0700,
Ian Lance Taylor wrote:
>
> Momchil Ivanov <momchil@xxxxxxx> writes:
>
> > gcc 4.5 and 4.6 produce different output when compiled with -std=c99 than gcc 4.2 and 4.4.
>
> In gcc 4.5 and up -std=c99 implies -fexcess-precision=standard, q.v.
>
> Ian
Thank you for the tip, but I still don't understand why the following produces different output for both floats when compiled with -fexcess-precision=standard:
#include <stdio.h>
int
main(int argc, char *argv[])
{
float a = 268517138.f;
printf(" 268517138.f = %f\t%f\n", 268517138.f, a);
return 0;
}
output with -fexcess-precision=standard:
268517138.f = 268517138.000000 268517152.000000
output without -fexcess-precision=standard:
268517138.f = 268517152.000000 268517152.000000
Regards,
Momchil
