Objective c IONotificationPortDestroy-打电话还是不打？

我有代码可以在OS X 10.7.4上使用XCode 4.3.3设置USB设备添加/删除通知。对于带有myVid和myPid的USB设备，这是一个很好的样板：

// Global declarations somewhere near the top of the file.  
IONotificationPortRef g_notificationPort= NULL;  
io_object_t g_notification= 0;  
io_iterator_t g_iteratorAdded= 0; 
.
.
.
- (BOOL)setupDeviceNotification  
{  
// Set up matching dictionary.  
NSMutableDictionary* matchingDictionary= (NSMutableDictionary*)IOServiceMatching(kIOUSBDeviceClassName);  
[matchingDictionary setObject:[NSNumber numberWithLong:myVid] forKey:[NSString stringWithUTF8String:kUSBVendorID]];  
[matchingDictionary setObject:[NSNumber numberWithLong:myPid] forKey:[NSString stringWithUTF8String:kUSBProductID]];  

// Create a run loop source for the notification object.  
g_notificationPort= IONotificationPortCreate(kIOMasterPortDefault);  
CFRunLoopSourceRef notificationRunLoopSource= IONotificationPortGetRunLoopSource(g_notificationPort);  
CFRunLoopAddSource(CFRunLoopGetCurrent(), notificationRunLoopSource, kCFRunLoopDefaultMode);  

// Set up a notification callback for device addition on first match.  
kern_return_t kRet= IOServiceAddMatchingNotification(g_notificationPort, kIOFirstMatchNotification, (CFMutableDictionaryRef)matchingDictionary, deviceAddedCallback, (void*)self, &g_iteratorAdded);  

// Rudimentary error handling.  
if(KERN_SUCCESS != kRet)  
{  
  [matchingDictionary release];  
  return FALSE;  
}  

// Arm the notification and check for existing devices.  
[self deviceWasAdded:g_iteratorAdded];  

return TRUE;
}

这段代码运行良好，当添加设备时，我使用IoniotificationPortRef使用IOServiceAddInterestNotification并将设置在全局对象中的io_对象存储起来

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在分析这段代码进行一些重构（将全局变量转换为类中的对象变量）后，我意识到我从来没有在我的IoniotificationPortRef对象上调用IoniotificationPortDestroy。我应该叫它吗？另外，我没有对IOServiceAddInterestNotification中分配的io对象做任何事情-那里需要清理吗？

好的，在翻阅了大量苹果文档后，我发现我应该对io对象执行IOObjectRelease，这就是通知。我找到了一些参考资料，但最简单的是苹果开发者网站上的“用户模式USB设备仲裁”文档