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glibc  2.9
s_casin.c
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00001 /* Return arc sine of complex double value.
00002    Copyright (C) 1997 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
00005 
00006    The GNU C Library is free software; you can redistribute it and/or
00007    modify it under the terms of the GNU Lesser General Public
00008    License as published by the Free Software Foundation; either
00009    version 2.1 of the License, or (at your option) any later version.
00010 
00011    The GNU C Library is distributed in the hope that it will be useful,
00012    but WITHOUT ANY WARRANTY; without even the implied warranty of
00013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014    Lesser General Public License for more details.
00015 
00016    You should have received a copy of the GNU Lesser General Public
00017    License along with the GNU C Library; if not, write to the Free
00018    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00019    02111-1307 USA.  */
00020 
00021 #include <complex.h>
00022 #include <math.h>
00023 
00024 
00025 __complex__ double
00026 __casin (__complex__ double x)
00027 {
00028   __complex__ double res;
00029 
00030   if (isnan (__real__ x) || isnan (__imag__ x))
00031     {
00032       if (__real__ x == 0.0)
00033        {
00034          res = x;
00035        }
00036       else if (__isinf (__real__ x) || __isinf (__imag__ x))
00037        {
00038          __real__ res = __nan ("");
00039          __imag__ res = __copysign (HUGE_VAL, __imag__ x);
00040        }
00041       else
00042        {
00043          __real__ res = __nan ("");
00044          __imag__ res = __nan ("");
00045        }
00046     }
00047   else
00048     {
00049       __complex__ double y;
00050 
00051       __real__ y = -__imag__ x;
00052       __imag__ y = __real__ x;
00053 
00054       y = __casinh (y);
00055 
00056       __real__ res = __imag__ y;
00057       __imag__ res = -__real__ y;
00058     }
00059 
00060   return res;
00061 }
00062 weak_alias (__casin, casin)
00063 #ifdef NO_LONG_DOUBLE
00064 strong_alias (__casin, __casinl)
00065 weak_alias (__casin, casinl)
00066 #endif