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Diffstat (limited to 'libc/sysdeps/linux/common/bits/nan.h')
-rw-r--r--libc/sysdeps/linux/common/bits/nan.h48
1 files changed, 48 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/common/bits/nan.h b/libc/sysdeps/linux/common/bits/nan.h
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+++ b/libc/sysdeps/linux/common/bits/nan.h
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+/* `NAN' constant for IEEE 754 machines.
+ Copyright (C) 1992, 1996, 1997, 1999 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. */
+
+#ifdef __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 = { __nan_bytes };
+# define NAN (__nan_union.__d)
+
+#endif /* GCC. */