writing…

Socket 套接字就只是一个概念而已, 并不存在实体 (硬件), 如果一定要赋予它一个实体, 我们可以说那些控制信息就是套接字的实体, 或者说存放控制信息的内存空间就是套接字的实体

By default, all sockets are blocking.

默认情况下, 所有的套接字都是阻塞的.

IO Model

blocking I/O 阻塞 I/O

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non-blocking I/O 非阻塞 I/O

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I/O multiplexing 多路复用

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Socket Option 套接字选项

The most commonly used options are SO_KEEPALIVE, SO_RCVBUF, SO_SNDBUF, and SO_REUSEADDR.

Every TCP socket has a send buffer and a receiver buffer, and every UDP socket has a receive buffer. The SO_SNDBUF and SO_RCVBUF socket options let us change the sizes of these buffers.

# An example to limit receive buffer length and send buffer length

import socket

sock = socket.socket()

sock.getsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF)
sock.getsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF)

Further Reading

• Unix Network Programming