diff --git a/man2/getcpu.2 b/man2/getcpu.2
index 94c0635b2..0fc9b414a 100644
--- a/man2/getcpu.2
+++ b/man2/getcpu.2
@@ -9,7 +9,7 @@
 .\"
 .\" 2008, mtk, various edits
 .\"
-.TH GETCPU 2 2012-07-13 "Linux" "Linux Programmer's Manual"
+.TH GETCPU 2 2013-04-03 "Linux" "Linux Programmer's Manual"
 .SH NAME
 getcpu \- determine CPU and NUMA node on which the calling thread is running
 .SH SYNOPSIS
@@ -40,7 +40,9 @@ or
 .I node
 is NULL nothing is written to the respective pointer.
 
-The third argument to this system call is nowadays unused (see NOTES).
+The third argument to this system call is nowadays unused,
+and should be specified as NULL
+unless portability to Linux 2.6.23 or earlier is required (see NOTES).
 
 The information placed in
 .I cpu