C信号量编程模型（生产者消费者）

 

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

#define STORAGE_SIZE 5
#define PRODUCER_SPEED 2//模拟IO
#define CONSUMER_SPEED 1//模拟CPU预处理

char buff[STORAGE_SIZE];
sem_t full_sem, empty_sem;
void *producer(void *arg){

int index = 0;//指向当前要放入的位置

while(1){

sem_wait(&empty_sem);//P
buff[index]= 'a';
printf("produce a food: a at %d\n", index);
index = (index + 1) % STORAGE_SIZE;
sem_post(&full_sem);//V
sleep(PRODUCER_SPEED);
}
}
void *consumer(void *arg){

int index = 0;//指向当前要消费的位置

while(1){
sem_wait(&full_sem);//P
buff[index] = '\0';
printf("consume a food: a at %d\n", index);
index = (index + 1) % STORAGE_SIZE;
sem_post(&empty_sem);//V
sleep(CONSUMER_SPEED);
}
}


int main(){

pthread_t tid_p, tid_c;
sem_init(&full_sem, 0, 0);
sem_init(&empty_sem, 0, 5);

pthread_create(&tid_p, NULL, producer, NULL);
pthread_create(&tid_c, NULL, consumer, NULL);

pthread_join(tid_p, NULL);
pthread_join(tid_c, NULL);

return 0;
}