Re: [HACKERS] More on 6.4 on DEC Alpha + Digital Unix 4.0d + DEC C compiler

> > The reference platform never lies.
> In this case the reference platform is broken, IMHO.

Uh, yes. I was hoping that my statement was outrageous enough to be
prima facia absurd. Ha Ha. Pretty funny, eh?

> 1. Follow the ANSI spec and raise an error for exp() underflow.
> The ERRNO path is already OK for this, but the other would have
> to be made to read
>         if (!finite(*result) || *result == 0.0)
> and we'd have to fix the expected regress output.
> 2. Decide that we are smarter than the ANSI C authors and the
> inventors of libm, and that a small exp() result should quietly
> underflow to zero.  In that case the ERRNO path would have to read
>         if (errno == ERANGE && *result != 0.0)
> I like choice #1 myself.

OK, sounds good.

> BTW, while I was at it I took the time to figure out why the
> pow() part of the test was failing for me (I was getting zeroes
> instead of the expected "pow() result is out of range" error).
> Turns out that depending on which HPUX math library version you
> use, pow() might fail with EDOM rather than ERANGE for negative
> inputs.  I'll change the pow() code to check for either errno
> when I get a chance.

Hmm. Any chance of making that HP-specific? It would be a shame to make
every platform test for two values on every calculation...

Regards.

                  - Tom