diff --git a/man2/sigaltstack.2 b/man2/sigaltstack.2
index f3fda4414..997d80c20 100644
--- a/man2/sigaltstack.2
+++ b/man2/sigaltstack.2
@@ -169,7 +169,7 @@ T}	Thread safety	MT-Safe
 .TE
 
 .SH CONFORMING TO
-SUSv2, SVr4, POSIX.1-2001.
+POSIX.1-2001, POSIX.1-2009, SUSv2, SVr4.
 .SH NOTES
 The most common usage of an alternate signal stack is to handle the
 .B SIGSEGV