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| author | Joseph Myers <joseph@codesourcery.com> | 2017-08-31 16:39:25 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2017-08-31 16:39:25 +0000 |
| commit | c0c49d60cfeff3b2aa801d6598143a073989654a (patch) | |
| tree | 248bd1a808a8f2e27396ddfd1c04e5362d7e5da2 /math/math.h | |
| parent | 5ef1b2138d4236bb3616e612c5bc4dc328a9ffb2 (diff) | |
| download | glibc-c0c49d60cfeff3b2aa801d6598143a073989654a.tar.gz glibc-c0c49d60cfeff3b2aa801d6598143a073989654a.tar.xz glibc-c0c49d60cfeff3b2aa801d6598143a073989654a.zip | |
Simplify NAN definitions.
Similar to my patches for HUGE_VAL and INFINITY. this patch eliminates
the bits/nan.h headers. __builtin_nanf ("") is used to define NAN for
GCC 3.3 and later; the fallback is (0.0f / 0.0f), which is a constant
expression for a quiet NaN of type float, but raises a spurious
"invalid" exception outside static initializers, which seems the best
that can be done purely in standard C. Again, if anyone actually uses
a compiler with its own incompatible extension for producing a
constant quiet NaN, we can add compiler conditionals.
Tested for x86_64.
* math/math.h [__USE_ISOC99] (NAN): Define directly here. Do not
include <bits/nan.h>.
* math/Makefile (headers): Remove bits/nan.h.
* bits/nan.h: Remove.
* sysdeps/ieee754/bits/nan.h: Likewise.
* sysdeps/mips/bits/nan.h: Likewise.
Diffstat (limited to 'math/math.h')
| -rw-r--r-- | math/math.h | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/math/math.h b/math/math.h index 5f5a498b11..bbc1ab9bfa 100644 --- a/math/math.h +++ b/math/math.h @@ -65,8 +65,15 @@ __BEGIN_DECLS # define INFINITY HUGE_VALF # endif -/* Get machine-dependent NAN value (returned for some domain errors). */ -# include <bits/nan.h> +/* IEEE Not A Number. */ +# if __GNUC_PREREQ (3, 3) +# define NAN (__builtin_nanf ("")) +# else +/* This will raise an "invalid" exception outside static initializers, + but is the best that can be done in ISO C while remaining a + constant expression. */ +# define NAN (0.0f / 0.0f) +# endif #endif /* __USE_ISOC99 */ #if __GLIBC_USE (IEC_60559_BFP_EXT) |