prodcons/prodcons.c

   1 #include <semaphore.h>
   2 #include <unistd.h>
   3 #include <pthread.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6
   7 #define MAX 6
   8 #define BUF_SIZE 3
   9 typedef struct args {
  10         sem_t sem_free;
  11         sem_t sem_busy;
  12 } args_t;
  13 static int buf[BUF_SIZE];
  14 void *prod(void *arg);
  15 void *cons(void *arg);
  16
  17 int main()
  18 {
  19         pthread_t t1, t2;
  20         args_t args;
  21         sem_init(&args.sem_free, 0, BUF_SIZE);
  22         sem_init(&args.sem_busy, 0, 0);
  23         pthread_create(&t1, NULL, prod, &args);
  24         pthread_create(&t2, NULL, cons, &args);
  25         pthread_join(t1, NULL);
  26         pthread_join(t2, NULL);
  27         printf("exit\n");
  28         return EXIT_SUCCESS;
  29 }
  30
  31 void *prod(void *arg)
  32 {
  33         int ip = 0, nbprod = 0, obj = 1001;
  34         args_t *args = (args_t *) arg;
  35         while (nbprod < MAX) {
  36                 sem_wait(&args->sem_free);
  37                 buf[ip] = obj;
  38                 sem_post(&args->sem_busy);
  39                 printf("prod: buf[%d]=%d\n", ip, obj);
  40                 obj++;
  41                 nbprod++;
  42                 ip = (ip + 1) % BUF_SIZE;
  43         }
  44         return NULL;
  45 }
  46
  47 void *cons(void *arg)
  48 {
  49         int ic = 0, nbcons = 0, obj;
  50         args_t *args = (args_t *) arg;
  51         while (nbcons < MAX) {
  52                 sleep(1);
  53                 sem_wait(&args->sem_busy);
  54                 obj = buf[ic];
  55                 sem_post(&args->sem_free);
  56                 printf("cons: buf[%d]=%d\n", ic, obj);
  57                 nbcons++;
  58                 ic = (ic + 1) % BUF_SIZE;
  59         }
  60         return NULL;
  61 }