glibc/sysdeps/ieee754/nan.h
1995-02-18 01:27:10 +00:00

47 lines
1.4 KiB
C

/* `NAN' constant for IEEE 754 machines.
Copyright (C) 1992 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#ifndef _NAN_H
#define _NAN_H 1
/* IEEE Not A Number. */
#include <endian.h>
#if __BYTE_ORDER == __BIG_ENDIAN
#define __nan_bytes { 0x7f, 0xf8, 0, 0, 0, 0, 0, 0 }
#endif
#if __BYTE_ORDER == __LITTLE_ENDIAN
#define __nan_bytes { 0, 0, 0, 0, 0, 0, 0xf8, 0x7f }
#endif
#ifdef __GNUC__
#define NAN \
(__extension__ ((union { unsigned char __c[8]; \
double __d; }) \
{ __nan_bytes }).__d)
#else /* Not GCC. */
static CONST char __nan[8] = __nan_bytes;
#define NAN (*(CONST double *) __nan)
#endif /* GCC. */
#endif /* nan.h */