diff --git a/pty_darwin.go b/pty_darwin.go
index 0f2bd58..4f4d5ca 100644
--- a/pty_darwin.go
+++ b/pty_darwin.go
@@ -52,11 +52,9 @@ func ptsname(f *os.File) (string, error) {
 }
 
 func grantpt(f *os.File) error {
-	var u _C_int
-	return ioctl(f.Fd(), syscall.TIOCPTYGRANT, uintptr(unsafe.Pointer(&u)))
+	return ioctl(f.Fd(), syscall.TIOCPTYGRANT, 0)
 }
 
 func unlockpt(f *os.File) error {
-	var u _C_int
-	return ioctl(f.Fd(), syscall.TIOCPTYUNLK, uintptr(unsafe.Pointer(&u)))
+	return ioctl(f.Fd(), syscall.TIOCPTYUNLK, 0)
 }
diff --git a/pty_freebsd.go b/pty_freebsd.go
index 17abe28..b341bab 100644
--- a/pty_freebsd.go
+++ b/pty_freebsd.go
@@ -7,10 +7,6 @@ import (
 	"unsafe"
 )
 
-const (
-	SPECNAMELEN = 63 /* max length of devicename <sys/param.h> */
-)
-
 func posix_openpt(oflag int) (fd int, err error) {
 	r0, _, e1 := syscall.Syscall(syscall.SYS_POSIX_OPENPT, uintptr(oflag), 0, 0)
 	fd = int(r0)
@@ -21,7 +17,7 @@ func posix_openpt(oflag int) (fd int, err error) {
 }
 
 func open() (pty, tty *os.File, err error) {
-	fd, err := posix_openpt(syscall.O_RDWR)
+	fd, err := posix_openpt(syscall.O_RDWR | syscall.O_CLOEXEC)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -40,9 +36,8 @@ func open() (pty, tty *os.File, err error) {
 }
 
 func isptmaster(fd uintptr) (bool, error) {
-	var result int
-	err := ioctl(fd, syscall.TIOCPTMASTER, uintptr(unsafe.Pointer(&result)))
-	return (result == 0), err
+	err := ioctl(fd, syscall.TIOCPTMASTER, 0)
+	return err == nil, err
 }
 
 var (
@@ -59,7 +54,7 @@ func ptsname(f *os.File) (string, error) {
 		return "", syscall.EINVAL
 	}
 
-	const n = SPECNAMELEN + 1
+	const n = _C_SPECNAMELEN + 1
 	var (
 		buf = make([]byte, n)
 		arg = fiodgnameArg{Len: n, Buf: (*byte)(unsafe.Pointer(&buf[0]))}
diff --git a/pty_linux.go b/pty_linux.go
index a1278b8..6e5a042 100644
--- a/pty_linux.go
+++ b/pty_linux.go
@@ -46,5 +46,6 @@ func ptsname(f *os.File) (string, error) {
 
 func unlockpt(f *os.File) error {
 	var u _C_int
+	// use TIOCSPTLCK with a zero valued arg to clear the slave pty lock
 	return ioctl(f.Fd(), ioctl_TIOCSPTLCK, uintptr(unsafe.Pointer(&u)))
 }
diff --git a/types_freebsd.go b/types_freebsd.go
index 7e0cfe8..ce3eb95 100644
--- a/types_freebsd.go
+++ b/types_freebsd.go
@@ -2,7 +2,14 @@
 
 package pty
 
-// #include <sys/filio.h>
+/*
+#include <sys/param.h>
+#include <sys/filio.h>
+*/
 import "C"
 
+const (
+	_C_SPECNAMELEN = C.SPECNAMELEN /* max length of devicename */
+)
+
 type fiodgnameArg C.struct_fiodgname_arg
diff --git a/ztypes_arm.go b/ztypes_arm.go
new file mode 100644
index 0000000..ff0b8fd
--- /dev/null
+++ b/ztypes_arm.go
@@ -0,0 +1,9 @@
+// Created by cgo -godefs - DO NOT EDIT
+// cgo -godefs types.go
+
+package pty
+
+type (
+	_C_int  int32
+	_C_uint uint32
+)
diff --git a/ztypes_freebsd_386.go b/ztypes_freebsd_386.go
index a7894a6..d997537 100644
--- a/ztypes_freebsd_386.go
+++ b/ztypes_freebsd_386.go
@@ -3,6 +3,10 @@
 
 package pty
 
+const (
+	_C_SPECNAMELEN = 0x3f
+)
+
 type fiodgnameArg struct {
 	Len int32
 	Buf *byte
diff --git a/ztypes_freebsd_amd64.go b/ztypes_freebsd_amd64.go
index 9d07d3f..5fa102f 100644
--- a/ztypes_freebsd_amd64.go
+++ b/ztypes_freebsd_amd64.go
@@ -3,6 +3,10 @@
 
 package pty
 
+const (
+	_C_SPECNAMELEN = 0x3f
+)
+
 type fiodgnameArg struct {
 	Len       int32
 	Pad_cgo_0 [4]byte
diff --git a/ztypes_freebsd_arm.go b/ztypes_freebsd_arm.go
new file mode 100644
index 0000000..d997537
--- /dev/null
+++ b/ztypes_freebsd_arm.go
@@ -0,0 +1,13 @@
+// Created by cgo -godefs - DO NOT EDIT
+// cgo -godefs types_freebsd.go
+
+package pty
+
+const (
+	_C_SPECNAMELEN = 0x3f
+)
+
+type fiodgnameArg struct {
+	Len int32
+	Buf *byte
+}