math/s_cacos.c

   1 /* Return cosine of complex double value.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <complex.h>
  21 #include <math.h>
  22
  23 __complex__ double
  24 __cacos (__complex__ double x)
  25 {
  26   __complex__ double y;
  27   __complex__ double res;
  28
  29   y = __casin (x);
  30
  31   __real__ res = (double) M_PI_2 - __real__ y;
  32   __imag__ res = -__imag__ y;
  33
  34   return res;
  35 }
  36 weak_alias (__cacos, cacos)
  37 #ifdef NO_LONG_DOUBLE
  38 strong_alias (__cacos, __cacosl)
  39 weak_alias (__cacos, cacosl)
  40 #endif