iphone - 可达性是实时更新的（reachabilityWithHostName）吗？

Question

可能重复：
reachabilityWithHostName 示例

我有这个代码：

[[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 不响应某些响应，会自动调用reachabilityChanged 函数吗？