Re: [bug-gawk] Overflow to Infinity

[arnold]

"Andrew J. Schorr" <address@hidden> wrote:

> I don't think you get a different result when comparing +nan or -nan to 0,
> do you? Is there a way to test for NaN signedness?
> Perhaps this would work:
>
>
> +     if (isnan(val)) {
> +             sprintf(buf, "%g", val);
> +             strcpy(buf, buf[0] == '-' ? "-nan" : "+nan");

Well, I was relying on current sprintf behavior to produce -nan, which
is why I checked for "nan".

> But it seems like there ought to be a math library function to do this.
> After all, sprintf figures out the sign somehow. Does the 'signbit'
> function work with NaN values?

That's a new one on me. According to the man page, it should work on
NaNs and infinities.

Eli - does Windows support the signbit function? That would give us
a portable solution.

Thanks,

Arnold