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, write to the Free
18   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19   02111-1307 USA.  */
20
21#include <complex.h>
22#include <math.h>
23
24__complex__ double
25__cacos (__complex__ double x)
26{
27  __complex__ double y;
28  __complex__ double res;
29
30  y = __casin (x);
31
32  __real__ res = (double) M_PI_2 - __real__ y;
33  __imag__ res = -__imag__ y;
34
35  return res;
36}
37weak_alias (__cacos, cacos)
38#ifdef NO_LONG_DOUBLE
39strong_alias (__cacos, __cacosl)
40weak_alias (__cacos, cacosl)
41#endif
42