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| author | Zack Weinberg <zackw@panix.com> | 2017-09-01 11:19:47 -0400 |
|---|---|---|
| committer | Zack Weinberg <zackw@panix.com> | 2017-09-01 11:19:47 -0400 |
| commit | a617bd119f1b36a7ff2d2fdecf0d2f56970d0288 (patch) | |
| tree | afc91c5ecccb67e03ac2d4b436b5a56a53fc93bd /math | |
| parent | ce870587d5055437619680700ee5663a3cec66f6 (diff) | |
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math/math.h (HUGE_VAL): Improve commentary.
Diffstat (limited to 'math')
| -rw-r--r-- | math/math.h | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/math/math.h b/math/math.h index bbc1ab9bfa..547b36d10e 100644 --- a/math/math.h +++ b/math/math.h @@ -37,11 +37,16 @@ __BEGIN_DECLS /* Gather machine dependent type support. */ #include <bits/floatn.h> -/* Value returned on overflow. On all IEEE754 machines, this is - +Infinity. */ +/* Value returned on overflow. With IEEE 754 floating point, this is + +Infinity, otherwise the largest representable positive value. */ #if __GNUC_PREREQ (3, 3) # define HUGE_VAL (__builtin_huge_val ()) #else +/* This may provoke compiler warnings, and may not be rounded to + +Infinity in all IEEE 754 rounding modes, but is the best that can + be done in ISO C while remaining a constant expression. 10,000 is + greater than the maximum (decimal) exponent for all supported + floating-point formats and widths. */ # define HUGE_VAL 1e10000 #endif #ifdef __USE_ISOC99 |