options :
```
- n_phi -> number_of_philosophers
- t_die -> time_to_die
- t_eat -> time_to_eat
- t_slp -> time_to_sleep
- n_est -> [number_of_times_each_philosopher_must_eat]
```

thread :
- thread are light-weight-process (LWP) that happens inside a process
- a process can be single-threaded or multi-threaded
- different process have a unique PID with a unique LWP, different thread in the same process have the same PID and a different LWP
- thread vs process :
  process :
  - process is isolated, it doesn't share memory with any other process
  - process can have states : new, ready, running, waiting, terminated, suspended
  - process is less efficient in communication, it takes more times to create or terminate or switch
  - process speed is not impacted by speed of other process (untill it reach the limit of cpu)
  - process are created with fork() and execve() (to duplicate a process in a child process, or replacing an existing process)
  thread :
  - thread are not isolated
  - thread can have states : running, ready, blocked
  - thread is more efficient in communication, it takes less times to create or terminate or switch
  - thread can become slow if the process does many concurrent tasks
- ressources :
  - https://www.baeldung.com/linux/process-vs-thread


external function :

memset : fill memory with a constant byte
printf : format and print data
malloc : allocate dynamic memory
free : free dynamic memory
write : write to a file descriptor
usleep : suspend execution for microseconds intervals
gettimeofday : get time
pthread_create : create a new thread
pthread_detach : 
pthread_join
pthread_mutex_init
pthread_mutex_destroy
pthread_mutex_lock
pthread_mutex_unlock