marjc5/philosophers

Basics of threading a process, see how to create threads and discover mutexes.

Project n°9 - Philosophers

basics of threading a process, see how to create threads and discover mutexes.

Goals

Here are the things you need to know if you want to succeed this assignment:

• One or more philosophers sit at a round table. There is a large bowl of spaghetti in the middle of the table.
• The philosophers alternatively eat, think, or sleep.
  1. While they are eating, they are not thinking nor sleeping;
  2. while thinking, they are not eating nor sleeping;
  3. and, of course, while sleeping, they are not eating nor thinking.
• There are also forks on the table. There are as many forks as philosophers.
• Because serving and eating spaghetti with only one fork is very inconvenient, a philosopher takes their right and their left forks to eat, one in each hand.
• When a philosopher has finished eating, they put their forks back on the table and start sleeping. Once awake, they start thinking again. The simulation stops when a philosopher dies of starvation.
• Every philosopher needs to eat and should never starve.
• Philosophers don’t speak with each other.
• Philosophers don’t know if another philosopher is about to die.
• No need to say that philosophers should avoid dying!

Rules

Program(s) should take the following arguments: number_of_philosophers time_to_die time_to_eat time_to_sleep [number_of_times_each_philosopher_must_eat]

• number_of_philosophers: The number of philosophers and also the number of forks.
• time_to_die (in milliseconds): If a philosopher didn’t start eating time_to_die milliseconds since the beginning of their last meal or the beginning of the sim- ulation, they die.
• time_to_eat (in milliseconds): The time it takes for a philosopher to eat. During that time, they will need to hold two forks.
• time_to_sleep (in milliseconds): The time a philosopher will spend sleeping.
• number_of_times_each_philosopher_must_eat (optional argument): If all philosophers have eaten at least number_of_times_each_philosopher_must_eat times, the simulation stops. If not specified, the simulation stops when a philosopher dies.

Test

Here is the test values:

./philo 1 800 200 200 (die)
./philo 5 800 200 200 (no die)
./philo 5 800 200 200 10 > result.txt (stop after each philo eat 10 times)
./philo 4 410 200 200 (no die)
./philo 4 310 200 200 (die)

External functs

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