bits/inf.h

   1 /* Default `INFINITY' constant.
   2    Copyright (C) 2004 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _MATH_H
  21 # error "Never use <bits/inf.h> directly; include <math.h> instead."
  22 #endif
  23
  24 /* If we don't have real infinity, then we're supposed to produce a float
  25    value that overflows at translation time, which is required to produce
  26    a diagnostic.  GCC's __builtin_inff produces a quite nice diagnostic
  27    that tells the user that the target doesn't support infinities.  */
  28
  29 #if __GNUC_PREREQ(3,3)
  30 # define INFINITY       (__builtin_inff())
  31 #else
  32 # define INFINITY       (1e9999f)
  33 #endif