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01: /* `HUGE_VAL' constant for IEEE 754 machines (where it is infinity).
02:    Used by <stdlib.h> and <math.h> functions for overflow.
03:    Copyright (C) 1992, 1995, 1996, 1997, 1999, 2000, 2004
04:    Free Software Foundation, Inc.
05:    This file is part of the GNU C Library.
06: 
07:    The GNU C Library is free software; you can redistribute it and/or
08:    modify it under the terms of the GNU Lesser General Public
09:    License as published by the Free Software Foundation; either
10:    version 2.1 of the License, or (at your option) any later version.
11: 
12:    The GNU C Library is distributed in the hope that it will be useful,
13:    but WITHOUT ANY WARRANTY; without even the implied warranty of
14:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15:    Lesser General Public License for more details.
16: 
17:    You should have received a copy of the GNU Lesser General Public
18:    License along with the GNU C Library; if not, write to the Free
19:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
20:    02111-1307 USA.  */
21: 
22: #ifndef _MATH_H
23: # error "Never use <bits/huge_val.h> directly; include <math.h> instead."
24: #endif
25: 
26: /* IEEE positive infinity (-HUGE_VAL is negative infinity).  */
27: 
28: #if __GNUC_PREREQ(3,3)
29: # define HUGE_VAL       (__builtin_huge_val())
30: #elif __GNUC_PREREQ(2,96)
31: # define HUGE_VAL       (__extension__ 0x1.0p2047)
32: #elif defined __GNUC__
33: 
34: # define HUGE_VAL \
35:   (__extension__                                                              \
36:    ((union { unsigned __l __attribute__((__mode__(__DI__))); double __d; })   \
37:     { __l: 0x7ff0000000000000ULL }).__d)
38: 
39: #else /* not GCC */
40: 
41: # include <endian.h>
42: 
43: typedef union { unsigned char __c[8]; double __d; } __huge_val_t;
44: 
45: # if __BYTE_ORDER == __BIG_ENDIAN
46: #  define __HUGE_VAL_bytes      { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 }
47: # endif
48: # if __BYTE_ORDER == __LITTLE_ENDIAN
49: #  define __HUGE_VAL_bytes      { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f }
50: # endif
51: 
52: static __huge_val_t __huge_val = { __HUGE_VAL_bytes };
53: # define HUGE_VAL       (__huge_val.__d)
54: 
55: #endif  /* GCC.  */
56: 

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