sysdeps/generic/infnan.c

   1 /* Copyright (C) 1991, 1995 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <math.h>
  22
  23 /* Deal with an infinite or NaN result.
  24    If ERROR is ERANGE, result is +Inf;
  25    if ERROR is - ERANGE, result is -Inf;
  26    otherwise result is NaN.
  27    This will set `errno' to either ERANGE or EDOM,
  28    and may return an infinity or NaN, or may do something else.  */
  29 double
  30 DEFUN(__infnan, (error), int error)
  31 {
  32   switch (error)
  33     {
  34     case ERANGE:
  35       errno = ERANGE;
  36       return HUGE_VAL;
  37
  38     case - ERANGE:
  39       errno = ERANGE;
  40       return - HUGE_VAL;
  41
  42     default:
  43       errno = EDOM;
  44       return 0.0;
  45     }
  46 }
  47
  48 weak_alias (__infnan, infnan)