| Renato Golin 2006-09-28, 1:20 pm |
| Aggelos Mpimpoudis wrote:
> But what about DaVinci? Did he managed to settle the pholosophers to eat
> (or I said something wrong at my reply earlier and he gave up :O  ???)
Ah, good point, I almost forgot of that. I could make his code work with
your advice and by putting the pthread_join later (otherwise it just sat
and waited). And btw, I put (i--) on phlosi so it won't go forever... ;)
Here's my full code:
#include<stdio.h>
#include<stdlib.h>
#include<pthread.h>
#define NUM 5
#define LEFT (i+NUM-1)%NUM
#define RIGHT (i+1)%NUM
#define FREE 0
#define USED 1
struct Fork
{
int flag;
int num;
};
static struct Fork *forks[NUM];
pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
pthread_t tid[NUM];
void
getting (int i)
{
pthread_mutex_lock (&lock);
if (forks[LEFT]->flag == FREE)
{
forks[LEFT]->flag = USED;
printf ("pholos%d picking fork %d\n", i, LEFT);
}
if (forks[RIGHT]->flag == FREE)
{
forks[RIGHT]->flag = USED;
printf ("pholos%d picking fork %d\n", i, RIGHT);
}
pthread_mutex_unlock (&lock);
return;
}
void
putting (int i)
{
pthread_mutex_lock (&lock);
forks[LEFT]->flag = FREE;
printf ("phlosi%d putting fork%d\n", i, LEFT);
pthread_mutex_unlock (&lock);
pthread_mutex_lock (&lock);
forks[RIGHT]->flag = FREE;
printf ("phlosi%d putting fork%d\n", i, RIGHT);
pthread_mutex_unlock (&lock);
}
void
thinking (int i)
{
printf ("phlosi%d is thingking\n", i);
sleep(1);
}
void
eatting (int i)
{
printf ("phlosi%d is eatting\n", i);
}
void
phlosi (int i)
{
while (i--)
{
thinking (i);
getting (i);
eatting (i);
putting (i);
}
}
int
main ()
{
int i=0, ret=0;
for (i=0; i<NUM; i++)
{
forks[i] = (struct Fork *) malloc (sizeof (struct Fork));
forks[i]->flag = FREE;
forks[i]->num = i;
}
for (i=0; i<NUM; i++)
{
ret = pthread_create (tid+i, NULL, (void *) phlosi, (void *) i);
if (ret)
return ret;
}
for (i=0; i<NUM; i++)
{
pthread_join(tid[i], NULL);
}
return 0;
}
|