Re: Use of C99 extra long double math functions after r236148

From: David Schultz <das_at_freebsd.org>
Date: Fri, 13 Jul 2012 11:58:05 -0400
On Fri, Jul 13, 2012, David Chisnall wrote:
> As do I.  I'd also point out that the ONLY requirement for long
> double according to the standard is that it has at least the same
> precision as double.  Therefore, any implementation of these
> functions that is no worse that the double version is compliant.
> Once we have something meeting a minimum standard, then I'm very
> happy to see it improved, but having C99 functions missing now is
> just embarrassing while we're working on adding C11 features.

There are several things wrong with this reasoning, but pragmatically
the conclusion may be right: we do have a long list of users who would
prefer a dubious implementation to none at all.

I propose we set a timeframe for this, on the order of a few months.
A rough outline might be something like:

  mid-August: expl logl log2l log10l
     -- just need to clean up Bruce and Steve's work; Steve recently
        sent me patches for expl, which I hope get committed soon
  mid-September: acoshl asinhl atanhl coshl sinhl tanhl
     -- easy once expl is in; others could probably help
  mid-October: powl expm1l
  mid-November: most complex.h functions

If the schedule can't be met, then we can just import Cephes as an
interim solution without further ado.  This provides Bruce and Steve
an opportunity to commit what they have been working on, without
forcing the rest of the FreeBSD community to wait indefinitely for
the pie in the sky.

By the way, the trig and complex functions are areas where anyone with
some calculus background could contribute.  If anyone is interested in
helping out, I'd be happy to coordinate things and review patches,
although I will be unavailable for much of August.
Received on Fri Jul 13 2012 - 13:58:13 UTC

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