philosophers

The training projects for learn the basics of threading a process

Description:

• 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!

Rules:

• Program takes 4 arguments:
  • int number_of__philosophers;
  • time_to_die (in milliseconds);
  • time_to_eat (in milliseconds);
  • time_to_sleep (in milliseconds);
  • number_of_times_each_philosopher_must_eat (optional argument);
• 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 Timestamp_in_ms with the current timestamp in milliseconds and X with the philosopher number.

Mandatory part (philo):

• 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.

Bonus part (philo_bonus):

• All the forks are put in the middle of the table.
• They have no states in memory but the number of available forks is represented by a semaphore.
• Each philosopher should be a process. But the main process should not be a philosopher.

Launch:

%>make
%>./philo 4 310 200 200

If you input this arguments, a philosopher should die! Strangely enough, a philosopher can starve to death while eating.