diff --git a/man4/tty_ioctl.4 b/man4/tty_ioctl.4
index ee279f818..850edd01f 100644
--- a/man4/tty_ioctl.4
+++ b/man4/tty_ioctl.4
@@ -370,6 +370,12 @@ is nonzero) or remove (if
 is zero) the pseudoterminal slave device.
 (See also
 .BR unlockpt (3).)
+.TP
+.BI "TIOCGPTLCK	int *" argp
+Place the current lock state of the pseudoterminal slave device
+in the location pointed to by
+.IR argp
+(since Linux 3.8).
 .PP
 The BSD ioctls
 .BR TIOCSTOP ,