/*
* Uses pickup_left_chopstick and pickup_right_chopstick
* to pick up the chopsticks
*/
void pickup_chopsticks(int phil_id){
if(phil_to_chopstick(phil_id, left) < phil_to_chopstick(phil_id, right))
{
pthread_mutex_lock(&chopstick_mutex[phil_to_chopstick(phil_id, left)]);
pickup_left_chopstick(phil_id);
pthread_mutex_lock(&chopstick_mutex[phil_to_chopstick(phil_id, right)]);
pickup_right_chopstick(phil_id);
}
else
{
pthread_mutex_lock(&chopstick_mutex[phil_to_chopstick(phil_id, right)]);
pickup_right_chopstick(phil_id);
pthread_mutex_lock(&chopstick_mutex[phil_to_chopstick(phil_id, left)]);
pickup_left_chopstick(phil_id);
}
}
/*
* Uses pickup_left_chopstick and pickup_right_chopstick
* to pick up the chopsticks
*/
void pickup_chopsticks(int phil_id){
/* simple solution, always pick up the chopstick with lower number */
int left_chopstick = (phil_id + 4) % 5;
int right_chopstick = phil_id;
if (left_chopstick < right_chopstick)
{
printf("Philosopher #%d tries to acquire left chopstick.\n", phil_id);
pthread_mutex_lock(&chopsticks[left_chopstick]);
pickup_left_chopstick(phil_id);
printf("Philosopher #%d tries to acquire right chopstick.\n", phil_id);
pthread_mutex_lock(&chopsticks[right_chopstick]);
pickup_right_chopstick(phil_id);
}
else
{
printf("Philosopher #%d tries to acquire right chopstick.\n", phil_id);
pthread_mutex_lock(&chopsticks[right_chopstick]);
pickup_right_chopstick(phil_id);
printf("Philosopher #%d tries to acquire left chopstick.\n", phil_id);
pthread_mutex_lock(&chopsticks[left_chopstick]);
pickup_left_chopstick(phil_id);
}
}