diff --git a/enumerator/usb_darwin.go b/enumerator/usb_darwin.go
index 1b1cbd1..2e653ec 100644
--- a/enumerator/usb_darwin.go
+++ b/enumerator/usb_darwin.go
@@ -28,7 +28,7 @@ func nativeGetDetailedPortsList() ([]*PortDetails, error) {
 	for _, service := range services {
 		defer service.Release()
 
-		port, err := extractPortInfo(C.io_registry_entry_t(service))
+		port, err := extractPortInfo(io_registry_entry_t(service))
 		if err != nil {
 			return nil, &PortEnumerationError{causedBy: err}
 		}
@@ -37,7 +37,7 @@ func nativeGetDetailedPortsList() ([]*PortDetails, error) {
 	return ports, nil
 }
 
-func extractPortInfo(service C.io_registry_entry_t) (*PortDetails, error) {
+func extractPortInfo(service io_registry_entry_t) (*PortDetails, error) {
 	port := &PortDetails{}
 	// If called too early the port may still not be ready or fully enumerated
 	// so we retry 5 times before returning error.
@@ -82,14 +82,14 @@ func extractPortInfo(service C.io_registry_entry_t) (*PortDetails, error) {
 	return port, nil
 }
 
-func getAllServices(serviceType string) ([]C.io_object_t, error) {
+func getAllServices(serviceType string) ([]io_object_t, error) {
 	i, err := getMatchingServices(serviceMatching(serviceType))
 	if err != nil {
 		return nil, err
 	}
 	defer i.Release()
 
-	var services []C.io_object_t
+	var services []io_object_t
 	tries := 0
 	for tries < 5 {
 		// Extract all elements from iterator
@@ -105,7 +105,7 @@ func getAllServices(serviceType string) ([]C.io_object_t, error) {
 		for _, s := range services {
 			s.Release()
 		}
-		services = []C.io_object_t{}
+		services = []io_object_t{}
 		i.Reset()
 		tries++
 	}
@@ -121,58 +121,64 @@ func serviceMatching(serviceType string) C.CFMutableDictionaryRef {
 }
 
 // getMatchingServices look up registered IOService objects that match a matching dictionary.
-func getMatchingServices(matcher C.CFMutableDictionaryRef) (C.io_iterator_t, error) {
+func getMatchingServices(matcher C.CFMutableDictionaryRef) (io_iterator_t, error) {
 	var i C.io_iterator_t
 	err := C.IOServiceGetMatchingServices(C.kIOMasterPortDefault, C.CFDictionaryRef(matcher), &i)
 	if err != C.KERN_SUCCESS {
 		return 0, fmt.Errorf("IOServiceGetMatchingServices failed (code %d)", err)
 	}
-	return i, nil
+	return io_iterator_t(i), nil
 }
 
 // CFStringRef
 
-func cfStringCreateWithString(s string) C.CFStringRef {
+type cfStringRef C.CFStringRef
+
+func cfStringCreateWithString(s string) cfStringRef {
 	c := C.CString(s)
 	defer C.free(unsafe.Pointer(c))
-	return C.CFStringCreateWithCString(
-		C.kCFAllocatorDefault, c, C.kCFStringEncodingMacRoman)
+	return cfStringRef(C.CFStringCreateWithCString(
+		C.kCFAllocatorDefault, c, C.kCFStringEncodingMacRoman))
 }
 
-func (ref C.CFStringRef) Release() {
+func (ref cfStringRef) Release() {
 	C.CFRelease(C.CFTypeRef(ref))
 }
 
 // CFTypeRef
 
-func (ref C.CFTypeRef) Release() {
-	C.CFRelease(ref)
+type cfTypeRef C.CFTypeRef
+
+func (ref cfTypeRef) Release() {
+	C.CFRelease(C.CFTypeRef(ref))
 }
 
 // io_registry_entry_t
 
-func (me *C.io_registry_entry_t) GetParent(plane string) (C.io_registry_entry_t, error) {
+type io_registry_entry_t C.io_registry_entry_t
+
+func (me *io_registry_entry_t) GetParent(plane string) (io_registry_entry_t, error) {
 	cPlane := C.CString(plane)
 	defer C.free(unsafe.Pointer(cPlane))
 	var parent C.io_registry_entry_t
-	err := C.IORegistryEntryGetParentEntry(*me, cPlane, &parent)
+	err := C.IORegistryEntryGetParentEntry(C.io_registry_entry_t(*me), cPlane, &parent)
 	if err != 0 {
 		return 0, errors.New("No parent device available")
 	}
-	return parent, nil
+	return io_registry_entry_t(parent), nil
 }
 
-func (me *C.io_registry_entry_t) CreateCFProperty(key string) (C.CFTypeRef, error) {
+func (me *io_registry_entry_t) CreateCFProperty(key string) (cfTypeRef, error) {
 	k := cfStringCreateWithString(key)
 	defer k.Release()
-	property := C.IORegistryEntryCreateCFProperty(*me, k, C.kCFAllocatorDefault, 0)
+	property := C.IORegistryEntryCreateCFProperty(C.io_registry_entry_t(*me), C.CFStringRef(k), C.kCFAllocatorDefault, 0)
 	if property == 0 {
 		return 0, errors.New("Property not found: " + key)
 	}
-	return property, nil
+	return cfTypeRef(property), nil
 }
 
-func (me *C.io_registry_entry_t) GetStringProperty(key string) (string, error) {
+func (me *io_registry_entry_t) GetStringProperty(key string) (string, error) {
 	property, err := me.CreateCFProperty(key)
 	if err != nil {
 		return "", err
@@ -191,7 +197,7 @@ func (me *C.io_registry_entry_t) GetStringProperty(key string) (string, error) {
 	return C.GoString(&buff[0]), nil
 }
 
-func (me *C.io_registry_entry_t) GetIntProperty(key string, intType C.CFNumberType) (int, error) {
+func (me *io_registry_entry_t) GetIntProperty(key string, intType C.CFNumberType) (int, error) {
 	property, err := me.CreateCFProperty(key)
 	if err != nil {
 		return 0, err
@@ -204,34 +210,52 @@ func (me *C.io_registry_entry_t) GetIntProperty(key string, intType C.CFNumberTy
 	return res, nil
 }
 
+func (me *io_registry_entry_t) Release() {
+	C.IOObjectRelease(C.io_object_t(*me))
+}
+
+func (me *io_registry_entry_t) GetClass() string {
+	class := make([]C.char, 1024)
+	C.IOObjectGetClass(C.io_object_t(*me), &class[0])
+	return C.GoString(&class[0])
+}
+
 // io_iterator_t
 
+type io_iterator_t C.io_iterator_t
+
 // IsValid checks if an iterator is still valid.
 // Some iterators will be made invalid if changes are made to the
 // structure they are iterating over. This function checks the iterator
 // is still valid and should be called when Next returns zero.
 // An invalid iterator can be Reset and the iteration restarted.
-func (me *C.io_iterator_t) IsValid() bool {
-	return C.IOIteratorIsValid(*me) == C.true
+func (me *io_iterator_t) IsValid() bool {
+	return C.IOIteratorIsValid(C.io_iterator_t(*me)) == C.true
 }
 
-func (me *C.io_iterator_t) Reset() {
-	C.IOIteratorReset(*me)
+func (me *io_iterator_t) Reset() {
+	C.IOIteratorReset(C.io_iterator_t(*me))
 }
 
-func (me *C.io_iterator_t) Next() (C.io_object_t, bool) {
-	res := C.IOIteratorNext(*me)
-	return res, res != 0
+func (me *io_iterator_t) Next() (io_object_t, bool) {
+	res := C.IOIteratorNext(C.io_iterator_t(*me))
+	return io_object_t(res), res != 0
+}
+
+func (me *io_iterator_t) Release() {
+	C.IOObjectRelease(C.io_object_t(*me))
 }
 
 // io_object_t
 
-func (me *C.io_object_t) Release() {
-	C.IOObjectRelease(*me)
+type io_object_t C.io_object_t
+
+func (me *io_object_t) Release() {
+	C.IOObjectRelease(C.io_object_t(*me))
 }
 
-func (me *C.io_object_t) GetClass() string {
+func (me *io_object_t) GetClass() string {
 	class := make([]C.char, 1024)
-	C.IOObjectGetClass(*me, &class[0])
+	C.IOObjectGetClass(C.io_object_t(*me), &class[0])
 	return C.GoString(&class[0])
 }