--- src/lib/libc/gen/ttyname.3	2003/06/17 04:26:42	1.2
+++ src/lib/libc/gen/ttyname.3	2005/11/19 22:32:53	1.3
@@ -31,7 +31,7 @@
 .\"
 .\"     @(#)ttyname.3	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD: src/lib/libc/gen/ttyname.3,v 1.5.2.3 2001/12/14 18:33:51 ru Exp $
-.\" $DragonFly: src/lib/libc/gen/ttyname.3,v 1.1 2003/06/16 04:25:56 dillon Exp $
+.\" $DragonFly$
 .\"
 .Dd June 4, 1993
 .Dt TTYNAME 3
@@ -47,6 +47,8 @@
 .In unistd.h
 .Ft char *
 .Fn ttyname "int fd"
+.Ft char *
+.Fn ttyname_r "int fd" "char *buf" "size_t len"
 .Ft int
 .Fn isatty "int fd"
 .Ft int
@@ -84,6 +86,11 @@ a file descriptor for which
 is true
 .Pp
 The
+.Fn ttyname_r
+function is a thread-safe version of
+.Fn ttyname
+.Pp
+The
 .Fn ttyslot
 function
 fetches the current process' control terminal number from the