glibc/sysdeps/libm-ieee754/s_cacos.c

/* Return cosine of complex double value.
   Copyright (C) 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <complex.h>
#include <math.h>

__complex__ double
__cacos (__complex__ double x)
{
  __complex__ double y;
  __complex__ double res;

  y = __casin (x);

  __real__ res = (double) M_PI_2 - __real__ y;
  __imag__ res = -__imag__ y;

  return res;
}
weak_alias (__cacos, cacos)
#ifdef NO_LONG_DOUBLE
strong_alias (__cacos, __cacosl)
weak_alias (__cacos, cacosl)
#endif