IONotificationPortDestroy - 打电话还是不打电话？

Question

我有代码在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myVid和myPid一个USB设备，它是相当样板：

// 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; 
} 

此代码工作得很好，并添加设备时，我使用IOServiceAddInterestNotification的IONotificationPortRef并存储在一个全局对象设置io_object_t使用。

分析此代码做一些重构（使全局变为类中的对象变量），我意识到我从来没有在IONotificationPortRef对象上调用IONotificationPortDestroy。我应该打电话吗？此外，我没有做任何IOServiceAddInterestNotification中分配的io_object_t - 是否有任何需要清理？

Answer 1

好的，我在苹果文档中找到很多东西之后发现的一件事情是，我应该在通知io_object_t上真正做一个IOObjectRelease。我发现了几个参考，但最简单的是在Apple开发人员网站的文档“用户模式USB设备仲裁”中。