math/w_atan2_compat.c

   1 /* Copyright (C) 2011-2021 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /*
  20  * wrapper atan2(y,x)
  21  */
  22
  23 #include <errno.h>
  24 #include <math.h>
  25 #include <math_private.h>
  26 #include <math-svid-compat.h>
  27 #include <libm-alias-double.h>
  28
  29
  30 #if LIBM_SVID_COMPAT
  31 double
  32 __atan2 (double y, double x)
  33 {
  34   double z;
  35
  36   if (__builtin_expect (x == 0.0 && y == 0.0, 0) && _LIB_VERSION == _SVID_)
  37     return __kernel_standard (y, x, 3); /* atan2(+-0,+-0) */
  38
  39   z = __ieee754_atan2 (y, x);
  40   if (__glibc_unlikely (z == 0.0 && y != 0.0 && isfinite (x)))
  41     __set_errno (ERANGE);
  42   return z;
  43 }
  44 libm_alias_double (__atan2, atan2)
  45 #endif