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