README.md

Socket Programming in C

Introduction

This project implements a server-client system using socket programming. The server is a math calculator, which responds with calculated result of expression requested by client.

There are three different type implementations of server:

1. server1.c is a single process server that can handle only one client at a time. If another client tries to chat with the server while one client session is going on the second client will receive an error message like "line busy!"
2. server2.c is a multi-process server that forks a process whenever it receives a new client request. Multiple clients will be able to chat with the server concurrently.
3. server3.c is a single process (single-threaded) server that uses select system call to handle multiple clients concurrently.

Flow of Server and Client program

How to Run?

Compilation

1. cd to project directory
2. Compile both server and client program using the following commands

gcc server.c -o server 
gcc client.c -c client 

Execution

1. Run the server's executable file using ./server <port_num_to_run_on>
2. Run the client's executable file using ./client <port_num_to_connect>
3. Both client and server will print a message if the server accepts client's request for connection

Note: replace 'server' with 'server1', 'server2' or 'server3' to run different types of server

Samples

server1

As we can see we can connect to only one client at a time, trying to connect second client throws line busy! error.

server2

As we can see, two different processes (process ids are shown while shutting down) were created to handle two different clients

server3

There was only one server, which is used select() system call to handle multiple clients. The clients are connected to different sockets with the server.

Comparison between server1, server2, server3

References

1. Socket Man Page
2. TCP Server Client in Linux
3. Multiple Chat Clients: One Thread in C++