1 Sockets

1. socket很像一個文件
2. 本質上,socket是一個文件描述符指向網絡設備而不是一個硬盤上的文件
3. int socket(int domain, int type, int protocol);
   1. domain is the addressing domain of socket
   2. HTTP traffic is over TCP, so that would be SOCK_STREAM. If we wanted to open a UDP socket, the keyword would be SOCK_DGRAM
   3. protocol is additional information about the protocol of the socket, but we will not need to use this option, so we’ll set it to 0.
   4. 成功返回文件描述符,失敗返回-1.

2 Addressing

2.1 Glossary of Structures and Functions

3 Storing an IP address in struct in_addr

參考:
https://www.usna.edu/Users/cs/aviv/classes/ic221/s16/lec/26/lec.html#coderef-bad_ref