c语言实现多个生产者和消费者.docVIP

操作系统的一个经典问题是生产者-消费者问题, 这涉及同步信号量和互斥信号量的应用, 在这里,我用线程的同步和互斥来实现. /** author 张文* 2008/06/20*/ #include stdio.h#include stdlib.h#include unistd.h#include pthread.h#include semaphore.h #define N 2???// 消费者或者生产者的数目#define M 10?// 缓冲数目 int in = 0;???// 生产者放置产品的位置int out = 0;?// 消费者取产品的位置 int buff[M] = {0};?// 缓冲初始化为0， 开始时没有产品 sem_t empty_sem;?// 同步信号量， 当满了时阻止生产者放产品sem_t full_sem;???// 同步信号量， 当没产品时阻止消费者消费pthread_mutex_t mutex;?// 互斥信号量， 一次只有一个线程访问缓冲 int product_id = 0;???//生产者idint prochase_id = 0;?//消费者id /* 打印缓冲情况 */void print(){int i;for(i = 0; i M; i++)?? printf(%d , buff[i]);printf(\n);} /* 生产者方法 */?void *product(){int id = ++product_id;while(1){?? // 用sleep的数量可以调节生产和消费的速度，便于观察?? sleep(1);?? //sleep(1);???? sem_wait(empty_sem);?? pthread_mutex_lock(mutex);???? in = in % M;?? printf(product%d in %d. like: \t, id, in);???? buff[in] = 1;???? print();???? ++in;???? pthread_mutex_unlock(mutex);?? sem_post(full_sem);??}} /* 消费者方法 */void *prochase(){int id = ++prochase_id;while(1){?? // 用sleep的数量可以调节生产和消费的速度，便于观察?? sleep(1);//sleep(1);???? sem_wait(full_sem);?? pthread_mutex_lock(mutex);???? out = out % M;?? printf(prochase%d in %d. like: \t, id, out);???? buff[out] = 0;?? print();?? ++out;???? pthread_mutex_unlock(mutex);?? sem_post(empty_sem);}} int main(){pthread_t id1[N];pthread_t id2[N];int i;int ret[N];// 初始化同步信号量int ini1 = sem_init(empty_sem, 0, M);?int ini2 = sem_init(full_sem, 0, 0);??if(ini1 ini2 != 0){?? printf(sem init failed \n);?? exit(1);}?//初始化互斥信号量?int ini3 = pthread_mutex_init(mutex, NULL);if(ini3 != 0){?? printf(mutex init failed \n);?? exit(1);}?// 创建N个生产者线程for(i = 0; i N; i++){?? ret[i] = pthread_create(id1[i], NULL, product, (void *)(i));?? if(ret[i] != 0)?? {??? printf(product%d creation failed \n, i);??? exit(1);?? }}//创建N个消费者线程for(i = 0; i N; i++){?? ret[i] = pthread_create(id2[i], NULL, prochase, NULL);?? if(ret[i] != 0)?? {??? printf(prochase%d