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. While they are eating they are not thinking nor sleeping; while thinking, they are not eating nor sleeping; 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!
You have to write a program for the mandatory part and another one for the bonus part (if you decide to do the bonus part). They both have to comply with the following rules:
- Global variables are forbidden!
- Your(s) 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 eatingtime_to_diemilliseconds since the beginning of their last meal or the beginning of the simulation, 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 leastnumber_of_times_each_philosopher_must_eattimes, the simulation stops. If not specified, the simulation stops when a philosopher dies.- Each philosopher has a number ranging from 1 to
number_of_philosophers. - Philosopher number 1 sits next to philosopher number
number_of_philosophers. Any other philosopher numberNsits between philosopher numberN - 1and philosopher numberN + 1.
About the logs of your program:
- Any state change of a philosopher must be formatted as follows:
- 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
Replace timestamp_in_ms with the current timestamp in milliseconds and X with the philosopher number.
- A displayed state message should not be mixed up with another message.
- A message announcing a philosopher died should be displayed no more than 10 ms after the actual death of the philosopher.
- Again, philosophers should avoid dying!
| Program name | philo |
| Turn in files | Makefile, *.h, *.c, in directory philo/ |
| Makefile | NAME, all, clean, fclean, re |
| Arguments | number_of_philosophers, time_to_die, time_to_eat, time_to_sleep, [number_of_times_each_philosopher_must_eat] |
| 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 |
| Libft authorized | No |
| Description | Philosophers with threads and mutexes |
The specific rules for the mandatory part are:
- Each philosopher should be a thread.
- There is one fork between each pair of philosophers. Therefore, if there are several philosophers, each philosopher has a fork on their left side and a fork on their right side. If there is only one philosopher, there should be only one fork on the table.
- To prevent philosophers from duplicating forks, you should protect the forks state with a mutex for each of them.