Implement C23 cospi

C23 adds various <math.h> function families originally defined in TS
18661-4.  Add the cospi functions (cos(pi*x)).

Tested for x86_64 and x86, and with build-many-glibcs.py.

1 files changed, 13 insertions, 0 deletions

diff --git a/manual/math.texi b/manual/math.texi
index e4f9122609..b818db2c1b 100644
--- a/manual/math.texi
+++ b/manual/math.texi
@@ -240,6 +240,19 @@ All these functions, including the @code{_Float@var{N}} and
 should be prepared to cope with their absence.
 @end deftypefun
 
+@deftypefun double cospi (double @var{x})
+@deftypefunx float cospif (float @var{x})
+@deftypefunx {long double} cospil (long double @var{x})
+@deftypefunx _FloatN cospifN (_Float@var{N} @var{x})
+@deftypefunx _FloatNx cospifNx (_Float@var{N}x @var{x})
+@standards{TS 18661-4:2015, math.h}
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+These functions return the cosine of pi multiplied by @var{x}.  The
+return value is in the range @code{-1} to @code{1}.
+
+The @code{cospi} functions are from TS 18661-4:2015.
+@end deftypefun
+
 @cindex complex trigonometric functions
 
 @w{ISO C99} defines variants of the trig functions which work on