A Comprehensive Guide to C++ Socket Programming

C++ Socket Programming facilitates communication between applications over a network. This guide covers essential concepts and provides a foundational understanding for beginners.

What is a Socket?

• A socket is an endpoint for sending or receiving data across a computer network.
• It is defined by an IP address and a port number.

Key Concepts

Types of Sockets

1. Stream Sockets (TCP):
   • Provide reliable, connection-oriented communication.
   • Utilize Transmission Control Protocol (TCP).
   • Data is delivered in order and without loss.
2. Datagram Sockets (UDP):
   • Provide connectionless communication.
   • Utilize User Datagram Protocol (UDP).
   • Data may arrive out of order, and delivery is not guaranteed.

Basic Steps in Socket Programming

1. Create a Socket:
   • Use the socket() function to create a socket.
2. Bind the Socket (Server-side):
   • Use bind() to associate the socket with an IP address and port number.
3. Listen for Connections (Server-side):
   • Use listen() to enable the server to accept incoming connections.
4. Accept Connections (Server-side):
   • Use accept() to accept a connection from a client.
5. Connect to a Server (Client-side):
   • Use connect() to establish a connection to the server.
6. Send and Receive Data:
   • Use send() and recv() functions for data transmission.
7. Close the Socket:
   • Use close() to terminate the socket connection.

Example:

close(sockfd);

Example:

send(sockfd, message, strlen(message), 0);
recv(sockfd, buffer, sizeof(buffer), 0);

Example:

connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));

Example:

int client_sock = accept(sockfd, (struct sockaddr *)&client_addr, &addr_len);

Example:

listen(sockfd, 5);

Example:

struct sockaddr_in server_addr;
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = INADDR_ANY;
server_addr.sin_port = htons(port);
bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));

Example:

int sockfd = socket(AF_INET, SOCK_STREAM, 0);

Conclusion

Socket programming in C++ is essential for network communication, involving creating sockets, binding them, listening for connections, and sending/receiving data. Understanding the differences between TCP and UDP sockets is crucial for selecting the appropriate protocol based on the application's requirements.

By mastering these fundamental concepts, beginners can start developing networked applications using C++ socket programming.