math/s_ccos.c

   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 <fenv.h>
  23 #include <math.h>
  24
  25
  26 __complex__ double
  27 __ccos (__complex__ double x)
  28 {
  29   __complex__ double res;
  30
  31   if (!isfinite (__real__ x) || __isnan (__imag__ x))
  32     {
  33       if (__real__ x == 0.0 || __imag__ x == 0.0)
  34         {
  35           __real__ res = __nan ("");
  36           __imag__ res = 0.0;
  37
  38 #ifdef FE_INVALID
  39           if (__isinf (__real__ x))
  40             feraiseexcept (FE_INVALID);
  41 #endif
  42         }
  43       else if (__isinf (__imag__ x))
  44         {
  45           __real__ res = HUGE_VAL;
  46           __imag__ res = __nan ("");
  47
  48 #ifdef FE_INVALID
  49           if (__isinf (__real__ x))
  50             feraiseexcept (FE_INVALID);
  51 #endif
  52         }
  53       else
  54         {
  55           __real__ res = __nan ("");
  56           __imag__ res = __nan ("");
  57
  58 #ifdef FE_INVALID
  59           if (isfinite (__imag__ x))
  60             feraiseexcept (FE_INVALID);
  61 #endif
  62         }
  63     }
  64   else
  65     {
  66       __complex__ double y;
  67
  68       __real__ y = -__imag__ x;
  69       __imag__ y = __real__ x;
  70
  71       res = __ccosh (y);
  72     }
  73
  74   return res;
  75 }
  76 weak_alias (__ccos, ccos)
  77 #ifdef NO_LONG_DOUBLE
  78 strong_alias (__ccos, __ccosl)
  79 weak_alias (__ccos, ccosl)
  80 #endif