math/s_casin.c

   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 }
  62 weak_alias (__casin, casin)
  63 #ifdef NO_LONG_DOUBLE
  64 strong_alias (__casin, __casinl)
  65 weak_alias (__casin, casinl)
  66 #endif