diff --git a/man2/sigprocmask.2 b/man2/sigprocmask.2
index 947d3739c..5c92f9894 100644
--- a/man2/sigprocmask.2
+++ b/man2/sigprocmask.2
@@ -26,7 +26,7 @@
 .\"
 .\" 2005-09-15, mtk, Created new page by splitting off from sigaction.2
 .\"
-.TH SIGPROCMASK 2 2012-04-15 "Linux" "Linux Programmer's Manual"
+.TH SIGPROCMASK 2 2013-04-19 "Linux" "Linux Programmer's Manual"
 .SH NAME
 sigprocmask \- examine and change blocked signals
 .SH SYNOPSIS
@@ -93,6 +93,9 @@ is unspecified in a multithreaded process; see
 .SH RETURN VALUE
 .BR sigprocmask ()
 returns 0 on success and \-1 on error.
+In the event of an error,
+.I errno
+is set to indicate the cause.
 .SH ERRORS
 .TP
 .B EFAULT