Multithreading

Introduction

Multithreading in C often uses POSIX pthreads — create threads, share address space, synchronize with mutexes.

Understanding the topic

pthread_create Start a new thread with entry function.

pthread_join Wait for thread completion.

Mutex Protect shared data from race conditions.

• pthread_create — Start a new thread with entry function.
• pthread_join — Wait for thread completion.
• Mutex — Protect shared data from race conditions.

Step-by-step explanation

1. pthread_create — Start a new thread with entry function.
2. pthread_join — Wait for thread completion.
3. Mutex — Protect shared data from race conditions.

Syntax reference

Syntax reference:

#include <pthread.h>

Execution workflow

Best practices

• Enable warnings: gcc -Wall -Wextra -std=c11 source.c -o app
• Give every variable a defined value before it is read.
• Stay inside array bounds — C will not stop you from over-running a buffer.

Common mistakes

• Reading uninitialized storage — behavior is undefined.
• Dismissing compiler warnings instead of fixing root causes.
• Ignoring NULL returns from malloc, fopen, and similar APIs.

Hands-on exercise

Practice problems:

• Two threads printing messages
• Mutex protecting counter

Summary

Multithreading in C — POSIX threads and basic synchronization.