math/w_atan2_compat.c

   1 /* Copyright (C) 2011-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 /*
  19  * wrapper atan2(y,x)
  20  */
  21
  22 #include <errno.h>
  23 #include <math.h>
  24 #include <math_private.h>
  25 #include <math-svid-compat.h>
  26 #include <libm-alias-double.h>
  27
  28
  29 #if LIBM_SVID_COMPAT
  30 double
  31 __atan2 (double y, double x)
  32 {
  33   double z;
  34
  35   if (__builtin_expect (x == 0.0 && y == 0.0, 0) && _LIB_VERSION == _SVID_)
  36     return __kernel_standard (y, x, 3); /* atan2(+-0,+-0) */
  37
  38   z = __ieee754_atan2 (y, x);
  39   if (__glibc_unlikely (z == 0.0 && y != 0.0 && isfinite (x)))
  40     __set_errno (ERANGE);
  41   return z;
  42 }
  43 libm_alias_double (__atan2, atan2)
  44 #endif