diff --git a/src/unix/mod.rs b/src/unix/mod.rs
index 1565b6338c12130220f9b750f649c891c291c304..9160af3f0cefa869889ac035af941acd7e64aba9 100644
--- a/src/unix/mod.rs
+++ b/src/unix/mod.rs
@@ -753,6 +753,8 @@ extern {
     pub fn tcgetpgrp(fd: ::c_int) -> pid_t;
     pub fn tcsetpgrp(fd: ::c_int, pgrp: ::pid_t) -> ::c_int;
     pub fn ttyname(fd: ::c_int) -> *mut c_char;
+    pub fn ttyname_r(fd: ::c_int,
+                     buf: *mut c_char, buflen: ::size_t) -> ::c_int;
     pub fn unlink(c: *const c_char) -> ::c_int;
     #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
                link_name = "wait$UNIX2003")]