Socket接口是TCP/IP网络的API，Socket接口定义了许多函数或例程，程序员可以用它们来开发TCP/IP网络上的应用程序。要学Internet上的TCP/IP网络编程，必须理解Socket接口。

　 　 Socket接口设计者最先是将接口放在Unix操作系统里面的。如果了解Unix系统的输入和输出的话，就很容易了解Socket了。网络的 Socket数据传输是一种特殊的I/O，Socket也是一种文件描述符。Socket也具有一个类似于打开文件的函数调用Socket()，该函数返 回一个整型的Socket描述符，随后的连接建立、数据传输等操作都是通过该Socket实现的。常用的Socket类型有两种：流式Socket （SOCK_STREAM）和数据报式Socket（SOCK_DGRAM）。流式是一种面向连接的Socket，针对于面向连接的TCP服务应用；数据 报式Socket是一种无连接的Socket，对应于无连接的UDP服务应用。-Socket interface is TCP/IP network API, Socket Interface defines a number of functions or routines, the programmer can use them to develop TCP/IP network applications. Study on the Internet want TCP/IP network programming, we must understand the Socket Interface.

Socket Interface Designer is the first interface on the Unix operating system inside. If you know Unix system input and output, then it is easy to understand the Socket. Socket data transmission network is a special kind of I/O, Socket is a file descr iptor. Socket also has a similar function call to open the file of the Socket (), the function return an integer of Socket descr iptor, then the connection set up, data transmission and other operations through the implementation of the Socket. Socket type commonly used in two ways: streaming Socket (SOCK_STREAM) and data reported type Socket (SOCK_DGRAM). Streaming is a connection-oriented Socket, for in the TCP connection-oriented service applications　Datagram Socket t