Basic POSIX Threads (pthread) Programming

This GitHub repository contains examples and explanations of basic POSIX Threads programming using C programming language.

Introduction

POSIX Threads (also known as Pthreads) is a POSIX standard for threads programming. It defines a set of C programming language constructs that can be used to create and manipulate threads. Threads are lightweight procedures that can run concurrently within a single process. By using threads, we can divide a complex task into smaller parts, which can be executed in parallel, thereby improving the overall performance of the application.

Table of Contents

1. Overview
2. Thread Creation
   • pthread_create.c This file demonstrates how to create a new thread using the pthread_create() function.
   • pthread_join.c This file demonstrates how to wait for a thread to complete its execution using the pthread_join() function.
   • pthread_multiple_threads.c This file demonstrates how to create and join multiple threads using a for loop.
3. Mutexes
   • pthread_shared_vars.c This file demonstrates how threads share memory.
   • pthread_race_condition.c This file demonstrates how the share memory may result in race conditions.
   • pthread_mutex.c This file demonstrates how to use a mutex to protect a critical section of code from concurrent access by multiple threads.
4. Arguments and Return Values in thread functions
   • pthread_return_value.c This file demonstrates how to return values from the thread functions.
     
   • pthread_exit.c This file demonstrates how to use pthread_exit to return values.
     
   • pthread_thread_arg.c This file demonstrates how to send arguments in thread functions.
     
5. Try Lock
   • pthread_trylock.c This file demonstrates how mutex lock is different from try lock.
     
6. Condition Variables
   • pthread_cond_var.c This file demonstrates how condition variables can be used.
     
   • pthread_cond_broadcast.c This file demonstrates how broadcast signal can be used.
     

Mini Projects

1. Finding array sum parallely
   • pthread_sum_array.c This file demonstrates how to sum an array parallely using two threads.
     
   • pthread_sum_array_mutex.c This file demonstrates how to sum an array parallely using mutex.
     
2. Stock Simulator
   • stocksimulator1.c This is a program that simulates a simple stock market where multiple threads (representing stock brokers) try to buy stocks until they are no longer available. It uses a mutex to synchronize access to the shared stock data and outputs a summary of how many stocks each broker bought.
     
   • stocksimulator2.c The second program builds on the first one by adding a stock exchange thread that periodically updates the stock price. The stock brokers only buy the stock if the price falls below a certain threshold, and they wait until the price drops before making a purchase using condition variables.
     

Prerequisites

To compile and run the code in this repository, you will need:

A C compiler (such as gcc) A POSIX Threads library (such as pthreads)

Usage

Go through each topic and run the code using:

On Windows:

gcc file_name.c -fopenmp

On Unix/Linux:

gcc file_name.c

Conclusion

This repository provides a starting point for learning about basic POSIX Threads programming. The examples provided here can be used as a reference for implementing multithreaded applications in C. If you have any questions or suggestions, feel free to open an issue or submit a pull request.

License

MIT