Advanced Mac OS X Programming: The Big Nerd Ranch Guide

Client Coding

Code on the client is very similar to the server:

1. Figure out the address information of the server.

2. Construct a struct sockaddr_in address.

3. Get a socket().

4. connect() to the server.

5. Use read() and write() to send and receive data.

connect

connect() makes the connection to the server. It returns a file descriptor that you read and write with.

int connect (int socket, const struct sockaddr *address, socklen_t addresslen);

Give it the address to connect to, and it returns zero if the connection succeeds or -1 for an error, with errno set.

Example 14.4 is a client that is a little more convenient than telnet. It follows telnet’s example in searching for the host address: first it does an IPv6 lookup and tries all addresses listed ...