diff --git a/man3/mblen.3 b/man3/mblen.3
index d3170ca70..a6140847c 100644
--- a/man3/mblen.3
+++ b/man3/mblen.3
@@ -97,7 +97,7 @@ T{
 T}	Thread safety	MT-Unsafe race
 .TE
 .SH CONFORMING TO
-C99.
+POSIX.1-2001, POSIX.1-2008, C99.
 .SH NOTES
 The behavior of
 .BR mblen ()