bugs

一个C编写网络广播的程序

* Synchronization points are still a weak point and need some work - 
  it's trivial to show, one client may block the whole transfer by simply
  not responding. Well. If it timeouts, it will be killed and (hopefully) 
  it will restart the transfer. Generally, some sort of client monitoring
  is needed. 
* On some systems (network cards, maybe) multicasting does not work - 
  when broadcasting does fine. It may be useful to create different
  methods of multi-destination transmission