实现了单个产品的输入与输出，望改进代码用多线程实现多生产者与多消费者

#include
#include
#include
#include
#include

#define MAX 256
char *buffer;
sem_t empty;
sem_t full;
sem_t mutex;

void *producer() {
sem_wait(&empty);
sem_wait(&mutex);
printf("input something to buffer:");
buffer = (char *) malloc(MAX);
fgets(buffer, MAX, stdin);
sem_post(&mutex);
sem_post(&full);
}

void *consumer() {
sem_wait(&full);
sem_wait(&mutex);
printf("read product from buffer:%s", buffer);
memset(buffer, 0, MAX);
sem_post(&mutex);
sem_post(&empty);
}

int main() {
pthread_t id_producer;
pthread_t id_consumer;
int ret;
sem_init(&empty, 0, 10);
sem_init(&full, 0, 0);
sem_init(&mutex, 0, 1);
ret = pthread_create(&id_producer, NULL, producer, NULL);
ret = pthread_create(&id_consumer, NULL, consumer, NULL);
pthread_join(id_producer, NULL);
pthread_join(id_consumer, NULL);
sem_destroy(&empty);
sem_destroy(&full);
sem_destroy(&mutex);
printf("The End\n");
}