bits/flt-eval-method.h

   1 /* Define __GLIBC_FLT_EVAL_METHOD.
   2    Copyright (C) 2016-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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 #ifndef _MATH_H
  20 # error "Never use <bits/flt-eval-method.h> directly; include <math.h> instead."
  21 #endif
  22
  23 /* __GLIBC_FLT_EVAL_METHOD is the value of FLT_EVAL_METHOD used to
  24    determine the evaluation method typedefs such as float_t and
  25    double_t.  It must be a value from C11 or TS 18661-3:2015, and not
  26    -1.  */
  27
  28 /* In the default version of this header, follow __FLT_EVAL_METHOD__.
  29    -1 is mapped to 2 (considering evaluation as long double to be a
  30    conservatively safe assumption), and if __FLT_EVAL_METHOD__ is not
  31    defined then assume there is no excess precision and use the value
  32    0.  */
  33
  34 #ifdef __FLT_EVAL_METHOD__
  35 # if __FLT_EVAL_METHOD__ == -1
  36 #  define __GLIBC_FLT_EVAL_METHOD       2
  37 # else
  38 #  define __GLIBC_FLT_EVAL_METHOD       __FLT_EVAL_METHOD__
  39 # endif
  40 #else
  41 # define __GLIBC_FLT_EVAL_METHOD        0
  42 #endif