多socket通信UDP源码，使用广播，多播地址，指定目的端口号-Multi-source UDP socket communication, broadcast, multicast address, specify the destination port number

用于广播的socket类, 网络编程 Multicast实现-Socket class library for broadcast, Multicast network programming implementation

指定源组播例子 ，感兴趣的人员可以参考一下，研究这方面的人不多了。(The following sample code illustrates how to include multicast functionality to a Windows Sockets application using socket options.)