#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>

static sem_t my_sem;
int the_end;

void *thread1_process (void * arg)
{
  while (!the_end) {
    printf ("Je t'attend !\n");
    sem_wait (&my_sem);
  }

  printf ("OK, je sors !\n");
  pthread_exit (0);
}

void *thread2_process (void * arg)
{
  register int i;

  for (i = 0 ; i < 5 ; i++) {
    printf ("J'arrive %d !\n", i);
    sem_post (&my_sem);
    sleep (1);
  }

  the_end = 1;
  sem_post (&my_sem); /* Pour debloquer le dernier sem_wait */
  pthread_exit (0);
}


main (int ac, char **av)
{
  pthread_t th1, th2;
  void *ret;

  sem_init (&my_sem, 0, 0);

  if (pthread_create (&th1, NULL, thread1_process, NULL) < 0) {
    fprintf (stderr, "pthread_create error for thread 1\n");
    exit (1);
  }

  if (pthread_create (&th2, NULL, thread2_process, NULL) < 0) {
    fprintf (stderr, "pthread_create error for thread 2\n");
    exit (1);
  }

  (void)pthread_join (th1, &ret);
  (void)pthread_join (th2, &ret);
}