diff --git a/pty/pty_darwin.go b/pty/pty_darwin.go
index d8b2343..b15343c 100644
--- a/pty/pty_darwin.go
+++ b/pty/pty_darwin.go
@@ -50,8 +50,7 @@ func getpt() (file *os.File, err error) {
 func ptsname(file *os.File) (name string, err error) {
 
 	n := make([]byte, (syscall.TIOCPTYGNAME>>16)&((1<<13)-1))
-	var err error
-	n, err = ioctl(file, syscall.TIOCPTYGNAME, uintptr(unsafe.Pointer(&n[0])))
+	_, err = ioctl(file, syscall.TIOCPTYGNAME, uintptr(unsafe.Pointer(&n[0])))
 	for i, c := range n {
 		if c == 0 {
 			return string(n[:i]), nil