可达性是实时更新（reachabilityWithHostName）？

Question

  

可能重复：
  reachabilityWithHostName Example

我有这段代码：

[[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(reachabilityChanged:) name: kReachabilityChangedNotification object: nil];
hostReach = [Reachability reachabilityWithHostName: @"www.apple.com"];
[hostReach startNotifier];    

- (void) reachabilityChanged: (NSNotification* )note{
Reachability* curReach = [note object];
NSParameterAssert([curReach isKindOfClass: [Reachability class]]);
}

我的问题是： 如果www.apple.com不会响应某些resone，则会自动调用reachabilityChanged函数吗？