On Sun, 4 Nov 2018, Ed Smith-Rowland wrote:
> I looked in glibc. Unfortunately, I see how they have the same mistake:
> glibc/math/w_tgammal_compat.c:
> long double
> __tgammal(long double x)
> {
> int local_signgam;
> long double y = __ieee754_gammal_r(x,&local_signgam);
> ...
> return local_signgam < 0 ? - y : y;
> }
> I'm very sure this is where tgammaq came from.
> Ditto for glibc/math/w_tgamma_compat.c and glibc/math/w_tgammaf_compat.c.
No, that's not a mistake. __ieee754_gammal_r returns +/- the gamma
function and sets the integer pointed to by the second argument to
indicate whether to negate the result. (This isn't a particularly good
interface design for tgamma, as opposed to lgamma; unfortunately
__gammal_r_finite, with this interface, is a public ABI.)
--
Joseph S. Myers
jos...@codesourcery.com
