Chapter 3: Standard BSD API Functions

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Overview

In this chapter, we take our first look at the details of the BSD Sockets API. This discussion is based on the Linux API, but this implementation follows the standard closely, so it will apply to other implementations as well. We focus on the basic Sockets API primitives first, and then in Chapter 4, Advanced Sockets Functions, we look at the more advanced functions. The Sockets functions that are discussed in this chapter are shown in Table 3.1.

Table 3.1: SOCKETS API FUNCTIONS DISCUSSED IN CHAPTER 3

Function	Description
socket	Creates a new socket endpoint
bind	Binds a local address to the socket
listen	Permits incoming connections for a server socket
accept	Accepts a new client connection for a server socket
connect	Connects to a server from a client socket
recv	Receives data through a socket
recvfrom	Receives data through a datagram socket
send	Sends data through a socket
sendto	Sends data through a datagram socket
close	Closes a socket endpoint
htons	Converts short to network byte order
ntohs	Converts short to host byte order
htonl	Converts long to network byte order
ntohl	Converts long to host byte order
inet_addr	Converts a dotted-notation string to a 32-bit network address
inet_ntoa	Converts a 32-bit network address to a dotted-notation string
inet_aton	Converts a dotted-notation string to a 32-bit network address

The following subsections illustrate the API calls, and discuss any special characteristics of their application and common problems that are associated in their use.

Note 

In this chapter, we demonstrate the calls as they appear in standard Linux distributions (which follows the BSD API). For embedded Sockets API implementations, the calls and include files may differ.

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