pow.3: RETURN VALUE: Clarify that -0.0 is a valid underflow result

The standards are a bit unclear (or I couldn't find it), but
Joseph confirmed that glibc documents this behavior, and
M. Welinder tested that Solaris also behaves in the same way.

Reported-by: M. Welinder <mwelinder@gmail.com>
Bug: 214815 <https://bugzilla.kernel.org/show_bug.cgi?id=214815>
Cc: Joseph Myers <joseph@codesourcery.com>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>

diff --git a/man3/pow.3 b/man3/pow.3
index ccf6375c04e5bc1da40abc1976b73aa3e6af06e6..69ddadc3ad8832d8b6ed42bf4b74923ea79d1501 100644 (file)
--- a/man3/pow.3
+++ b/man3/pow.3
@@ -82,7 +82,7 @@ respectively, with the mathematically correct sign.
 .PP
 If result underflows, and is not representable,
 a range error occurs,
-and 0.0 is returned.
+and 0.0 with the appropriate sign is returned.
 .\" POSIX.1 does not specify the sign of the zero,
 .\" but http://sources.redhat.com/bugzilla/show_bug.cgi?id=2678
 .\" points out that the zero has the wrong sign in some cases.