From a617bd119f1b36a7ff2d2fdecf0d2f56970d0288 Mon Sep 17 00:00:00 2001 From: Zack Weinberg Date: Fri, 1 Sep 2017 11:19:47 -0400 Subject: [PATCH] math/math.h (HUGE_VAL): Improve commentary. --- ChangeLog | 4 ++++ math/math.h | 9 +++++++-- 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index 4f8a12ca7c..32b304b8ac 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,7 @@ +2017-09-01 Zack Weinberg + + * math/math.h (HUGE_VAL): Improve commentary. + 2017-09-01 Adhemerval Zanella Andreas Schwab 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 -/* 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