sysdeps/x86/bits/huge_vall.h

   1 /* `HUGE_VALL' constant for ix86 (where it is infinity).
   2    Used by <stdlib.h> and <math.h> functions for overflow.
   3    Copyright (C) 1992-2015 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   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, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef _MATH_H
  21 # error "Never use <bits/huge_vall.h> directly; include <math.h> instead."
  22 #endif
  23
  24 #if __GNUC_PREREQ(3,3)
  25 # define HUGE_VALL      (__builtin_huge_vall())
  26 #elif __GNUC_PREREQ(2,96)
  27 # define HUGE_VALL      (__extension__ 0x1.0p32767L)
  28 #else
  29
  30 # define __HUGE_VALL_bytes      { 0, 0, 0, 0, 0, 0, 0, 0x80, 0xff, 0x7f, 0, 0 }
  31
  32 # define __huge_vall_t  union { unsigned char __c[12]; long double __ld; }
  33 # ifdef __GNUC__
  34 #  define HUGE_VALL     (__extension__ \
  35                          ((__huge_vall_t) { __c: __HUGE_VALL_bytes }).__ld)
  36 # else  /* Not GCC.  */
  37 static __huge_vall_t __huge_vall = { __HUGE_VALL_bytes };
  38 #  define HUGE_VALL     (__huge_vall.__ld)
  39 #  endif /* GCC.  */
  40
  41 #endif /* GCC 2.95 */