mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-05 03:01:05 +00:00
b575c52b86
2004-04-16 Ulrich Drepper <drepper@redhat.com> * sysdeps/ieee754/bits/nan.h (__nan_union): Add __attribute_used__ attribute to keep gcc quiet.
54 lines
1.6 KiB
C
54 lines
1.6 KiB
C
/* `NAN' constant for IEEE 754 machines.
|
|
Copyright (C) 1992, 1996, 1997, 1999, 2004 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 Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
#ifndef _MATH_H
|
|
# error "Never use <bits/nan.h> directly; include <math.h> instead."
|
|
#endif
|
|
|
|
|
|
/* IEEE Not A Number. */
|
|
|
|
#if __GNUC_PREREQ(3,3)
|
|
|
|
# define NAN (__builtin_nanf(""))
|
|
|
|
#elif defined__GNUC__
|
|
|
|
# define NAN \
|
|
(__extension__ \
|
|
((union { unsigned __l __attribute__((__mode__(__SI__))); float __d; }) \
|
|
{ __l: 0x7fc00000UL }).__d)
|
|
|
|
#else
|
|
|
|
# include <endian.h>
|
|
|
|
# if __BYTE_ORDER == __BIG_ENDIAN
|
|
# define __nan_bytes { 0x7f, 0xc0, 0, 0 }
|
|
# endif
|
|
# if __BYTE_ORDER == __LITTLE_ENDIAN
|
|
# define __nan_bytes { 0, 0, 0xc0, 0x7f }
|
|
# endif
|
|
|
|
static union { unsigned char __c[4]; float __d; } __nan_union
|
|
__attribute_used__ = { __nan_bytes };
|
|
# define NAN (__nan_union.__d)
|
|
|
|
#endif /* GCC. */
|