1
2#include <pthread.h>
3#include <stdlib.h>
4#include <unistd.h>
5
6/* Naive dining philosophers with inconsistent lock acquisition
7   ordering. */
8
9static pthread_t phil[5];
10static pthread_mutex_t chop[5];
11
12void* dine ( void* arg )
13{
14   int i;
15   long left = (long)arg;
16   long right = (left + 1) % 5;
17   for (i = 0; i < 1000/*arbitrary*/; i++) {
18      pthread_mutex_lock(&chop[left]);
19      pthread_mutex_lock(&chop[right]);
20      /* eating */
21      pthread_mutex_unlock(&chop[left]);
22      pthread_mutex_unlock(&chop[right]);
23   }
24   return NULL;
25}
26
27int main ( void )
28{
29   long i;
30   for (i = 0; i < 5; i++)
31      pthread_mutex_init( &chop[i], NULL);
32
33   for (i = 0; i < 5; i++)
34      pthread_create(&phil[i], NULL, dine, (void*)i );
35
36   sleep(1);
37
38   for (i = 0; i < 5; i++)
39      pthread_join(phil[i], NULL);
40
41   return 0;
42}
43