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[glibc/history.git] / math / s_casin.c
blob2d5b06cf7885073e2adb7a085b5b88f4db46253c
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.
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.
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.
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. */
21 #include <complex.h>
22 #include <math.h>
25 __complex__ double
26 __casin (__complex__ double x)
28 __complex__ double res;
30 if (isnan (__real__ x) || isnan (__imag__ x))
32 if (__real__ x == 0.0)
34 res = x;
36 else if (__isinf (__real__ x) || __isinf (__imag__ x))
38 __real__ res = __nan ("");
39 __imag__ res = __copysign (HUGE_VAL, __imag__ x);
41 else
43 __real__ res = __nan ("");
44 __imag__ res = __nan ("");
47 else
49 __complex__ double y;
51 __real__ y = -__imag__ x;
52 __imag__ y = __real__ x;
54 y = __casinh (y);
56 __real__ res = __imag__ y;
57 __imag__ res = -__real__ y;
60 return res;
62 weak_alias (__casin, casin)
63 #ifdef NO_LONG_DOUBLE
64 strong_alias (__casin, __casinl)
65 weak_alias (__casin, casinl)
66 #endif