생산자 소비자 - c 언어 실현

#include 
#include 
#include 
#include 
#include 
#include  

pthread_mutex_t mtx;
pthread_cond_t cond_add;
pthread_cond_t cond_del;
int pool;
int size;

#define THREADS 3
pthread_t tid_pd[THREADS];
pthread_t tid_cs[THREADS];

void producer(void *id)
{
	int threadid = *((int *)id);
	printf("producer threadid %d started.
", threadid);
	while(1) {
retry:
		pthread_mutex_lock(&mtx);
		if(pool >= size) {
			pthread_cond_wait(&cond_del, &mtx);
			pthread_mutex_unlock(&mtx);
			goto retry;
		}
		
		pool ++;
		printf("p%d add a good, pool is %d.
", threadid, pool);
		pthread_cond_signal(&cond_add);
		pthread_mutex_unlock(&mtx);
		srand((unsigned)time(NULL));

	}

	return;
}

void consumer(void *id)
{
	int threadid = *((int *)id);
	printf("consumer threadid %d started.
", threadid);
	while(1) {
retry:
		pthread_mutex_lock(&mtx);
		if(pool <= 0) {
			pthread_cond_wait(&cond_add, &mtx);
			pthread_mutex_unlock(&mtx);
			goto retry;
		}
		
		pool --;
		printf("c%d del a good, pool is %d.
", threadid, pool);
		pthread_cond_signal(&cond_del);
		pthread_mutex_unlock(&mtx);

	}

	return;
}

int main(int argc, char const *argv[])
{
	/* code */
	pthread_mutex_init(&mtx, NULL);
	pthread_cond_init(&cond_add, NULL);
	pthread_cond_init(&cond_del, NULL);
	pool = 0;
	size = 10;

	int i;
	for(i = 0; i < THREADS; i ++) {
		if(pthread_create(&tid_pd[i], NULL, (void *)producer, (void *)(&i)) != 0) {
			printf("create producer thread %d error!
", i);
			return 0;
		}
		usleep(100000);

	}
	for(i = 0; i < THREADS; i ++) {
		if(pthread_create(&tid_cs[i], NULL, (void *)consumer, (void *)(&i)) != 0) {
			printf("create consumer thread %d error!
", i);
			return 0;
		}
		usleep(100000);

	}

	for(i = 0; i < THREADS; i ++) {
		if(pthread_join(tid_pd[i], NULL) != 0) {
			printf("join producer thread %d error!
", i);
			return 0;
		}
	}
	for(i = 0; i < THREADS; i ++) {
		if(pthread_join(tid_cs[i], NULL) != 0) {
			printf("join consumer thread %d error!
", i);
			return 0;
		}
	}

	pthread_mutex_destroy(&mtx);
	pthread_cond_destroy(&cond_add);
	pthread_cond_destroy(&cond_del);

	return 0;
}