diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 15e949624..913084bd4 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,7 @@
+2013-06-13  Corinna Vinschen  <corinna@vinschen.de>
+
+	* posix.sgml (fcntl, flock, lockf): Point to implementation notes.
+
 2013-06-12  Fedin Pavel <p.fedin@samsung.com>
 
 	* path.cc (normalize_posix_path): Fix long-standing problem which
diff --git a/winsup/cygwin/posix.sgml b/winsup/cygwin/posix.sgml
index b88ecb973..26846a51a 100644
--- a/winsup/cygwin/posix.sgml
+++ b/winsup/cygwin/posix.sgml
@@ -188,7 +188,7 @@ also IEEE Std 1003.1-2008 (POSIX.1-2008).</para>
     fchown
     fchownat
     fclose
-    fcntl
+    fcntl			(see chapter "Implementation Notes")
     fdatasync
     fdim
     fdimf
@@ -418,7 +418,7 @@ also IEEE Std 1003.1-2008 (POSIX.1-2008).</para>
     localeconv
     localtime
     localtime_r
-    lockf
+    lockf			(see chapter "Implementation Notes")
     log
     log10
     log10f
@@ -977,7 +977,7 @@ also IEEE Std 1003.1-2008 (POSIX.1-2008).</para>
     finite
     finitef
     fiprintf
-    flock
+    flock			(see chapter "Implementation Notes")
     forkpty
     fpurge
     freeifaddrs