1/* Return arc sine 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
25__complex__ double
26__casin (__complex__ double x)
27{
28  __complex__ double res;
29
30  if (isnan (__real__ x) || isnan (__imag__ x))
31    {
32      if (__real__ x == 0.0)
33	{
34	  res = x;
35	}
36      else if (__isinf (__real__ x) || __isinf (__imag__ x))
37	{
38	  __real__ res = nan ("");
39	  __imag__ res = copysign (HUGE_VAL, __imag__ x);
40	}
41      else
42	{
43	  __real__ res = nan ("");
44	  __imag__ res = nan ("");
45	}
46    }
47  else
48    {
49      __complex__ double y;
50
51      __real__ y = -__imag__ x;
52      __imag__ y = __real__ x;
53
54      y = __casinh (y);
55
56      __real__ res = __imag__ y;
57      __imag__ res = -__real__ y;
58    }
59
60  return res;
61}
62weak_alias (__casin, casin)
63#ifdef NO_LONG_DOUBLE
64strong_alias (__casin, __casinl)
65weak_alias (__casin, casinl)
66#endif
67