diff --git a/doc.go b/doc.go
new file mode 100644
index 0000000..491c060
--- /dev/null
+++ b/doc.go
@@ -0,0 +1,11 @@
+// Package pty provides functions for working with Unix terminals.
+package pty
+
+import (
+	"os"
+)
+
+// Opens a pty and its corresponding tty.
+func Open() (pty, tty *os.File, err error) {
+	return open()
+}
diff --git a/pty_darwin.go b/pty_darwin.go
index c94a208..597bb03 100644
--- a/pty_darwin.go
+++ b/pty_darwin.go
@@ -10,8 +10,7 @@ import (
 // see ioccom.h
 const sys_IOCPARM_MASK = 0x1fff
 
-// Opens a pty and its corresponding tty.
-func Open() (pty, tty *os.File, err error) {
+func open() (pty, tty *os.File, err error) {
 	p, err := os.OpenFile("/dev/ptmx", os.O_RDWR, 0)
 	if err != nil {
 		return nil, nil, err
diff --git a/pty_linux.go b/pty_linux.go
index cecbbd6..3df1847 100644
--- a/pty_linux.go
+++ b/pty_linux.go
@@ -12,8 +12,7 @@ const (
 	sys_TIOCSPTLCK = 0x40045431
 )
 
-// Opens a pty and its corresponding tty.
-func Open() (pty, tty *os.File, err error) {
+func open() (pty, tty *os.File, err error) {
 	p, err := os.OpenFile("/dev/ptmx", os.O_RDWR, 0)
 	if err != nil {
 		return nil, nil, err