Philosophers 🤔

This project is part of the 42 school curriculum and simulates the dining philosophers problem, exploring concepts of threading, process management, and resource sharing.

Contents 📚

1. Problem Description
2. Project Structure
3. Installation
4. Usage
5. Implementation Details

Problem Description 📖

The dining philosophers problem is a classic computer science problem that illustrates synchronization issues and techniques for resolving them:

• Philosophers sit at a round table
• There is a bowl of spaghetti in the middle
• There are as many forks as philosophers
• Each philosopher needs two forks to eat
• Philosophers alternate between eating, thinking, and sleeping
• If a philosopher doesn't eat within a specified timeframe, they die

Project Structure 🗂️

philosophers/
├── philo/          # Mandatory part (threads & mutexes)
└── philo_bonus/    # Bonus part (processes & semaphores)

Installation 🛠️

# Clone the repository
git clone https://github.com/yourusername/philosophers.git

# Build mandatory part
cd philo
make

# Build bonus part
cd ../philo_bonus
make

Usage 💻

Mandatory Part

./philo number_of_philosophers time_to_die time_to_eat time_to_sleep [number_of_times_each_philosopher_must_eat]

Bonus Part

./philo_bonus number_of_philosophers time_to_die time_to_eat time_to_sleep [number_of_times_each_philosopher_must_eat]

Arguments 📝

• number_of_philosophers: The number of philosophers and forks
• time_to_die: Time (ms) after which a philosopher dies if they haven't eaten
• time_to_eat: Time (ms) it takes for a philosopher to eat
• time_to_sleep: Time (ms) a philosopher spends sleeping
• number_of_times_each_philosopher_must_eat: [Optional] Program stops when all philosophers eat this many times

Example Usage 🎯

# 5 philosophers, 800ms death time, 200ms eat time, 200ms sleep time
./philo 5 800 200 200

# With optional meals parameter (7 meals)
./philo 5 800 200 200 7

Implementation Details 🔧

Mandatory Part Features

• Threads for each philosopher
• Mutexes for fork management
• Death monitoring
• Thread-safe state printing

Bonus Part Features

• Processes for each philosopher
• Semaphores for fork management
• Inter-process communication
• Process monitoring and cleanup

Error Cases ⚠️

The program handles various error cases:

• Invalid numbers of philosophers
• Invalid time values
• Memory allocation failures
• Thread/process creation failures
• Mutex/semaphore initialization failures

Allowed Functions 📋

Mandatory Part

• memset
• printf
• malloc
• free
• write
• usleep
• gettimeofday
• pthread_create
• pthread_detach
• pthread_join
• pthread_mutex_init
• pthread_mutex_destroy
• pthread_mutex_lock
• pthread_mutex_unlock

Bonus Part

Additionally includes:

• fork
• kill
• exit
• waitpid
• sem_open
• sem_close
• sem_post
• sem_wait
• sem_unlink

Author 👤

• Alabar (hluiz-ma)

Acknowledgments 🙏

• 42 School
• Fellow 42 students