Philosophers

School 21 project to learn how to work with threads and processes, correctly share data between them. In the task, you need to solve the key multithreading problems: deadlock and simultaneous access to one resource. Here is 3 different programs that works with multithreading.

Rules

This project is to be coded in C, following the Norm. Any leak, crash, undefined

behavior or norm error means 0 to the project.

A number of philosophers are sitting at a round table doing one of three things:

eating, thinking or sleeping.

While eating, they are not thinking or sleeping, while sleeping, they are not eating

or thinking and of course, while thinking, they are not eating or sleeping.

The philosophers sit at a circular table with a large bowl of spaghetti in the center.

There are some forks on the table.

As spaghetti is difficult to serve and eat with a single fork, it is assumed that a

philosopher must eat with two forks, one for each hand.

The philosophers must never be starving.

Every philosopher needs to eat.

Philosophers don’t speak with each other.

Philosophers don’t know when another philosopher is about to die.

Each time a philosopher has finished eating, he will drop his forks and start sleeping.

When a philosopher is done sleeping, he will start thinking.

The simulation stops when a philosopher dies.

Each program should have the same options: number_of_philosophers time_to_die

time_to_eat time_to_sleep [number_of_times_each_philosopher_must_eat]

  ◦ number_of_philosophers: is the number of philosophers and also the number
  of forks
  ◦ time_to_die: is in milliseconds, if a philosopher doesn’t start eating ’time_to_die’
  milliseconds after starting his last meal or the beginning of the simulation, it
  dies

  ◦ time_to_eat: is in milliseconds and is the time it takes for a philosopher to 
  eat. During that time he will need to keep the two forks.

time_to_sleep: is in milliseconds and is the time the philosopher will spend sleeping.

number_of_times_each_philosopher_must_eat: argument is optional, if all philosophers eat at least ’number_of_times_each_philosopher_must_eat’ the

simulation will stop. If not specified, the simulation will stop only at the death of a philosopher.

Each philosopher should be given a number from 1 to ’number_of_philosophers’.

Philosopher number 1 is next to philosopher number ’number_of_philosophers’.

Any other philosopher with number N is seated between philosopher N - 1 and philosopher N + 1

Any change of status of a philosopher must be written as follows (with X replaced

with the philosopher number and timestamp_in_ms the current timestamp in milliseconds)

◦ timestamp_in_ms X has taken a fork

◦ timestamp_in_ms X is eating

◦ timestamp_in_ms X is sleeping

◦ timestamp_in_ms X is thinking

◦ timestamp_in_ms X died

The status printed should not be scrambled or intertwined with another philosopher’s status.

You can’t have more than 10 ms between the death of a philosopher and when it will print its death.

Philo_one

Do the task usign Threads and Mutex

Philo_two

Do the task usign Threads and Semaphore

Philo_three

Do the task usign Proccess and Semaphore

Run

1. To run this project you must be in philo_* directory

2. Run "make"

3. Run "sh philo_* [philo_count] [time to die] [time to eat] [time to sleep] [eat count (optional)]"