操作系统课程设计：用多线程同步方法解决读者阅览问题-白红宇

操作系统课程设计：用多线程同步方法解决读者阅览问题

阅读量：6654 次

发布时间：2019-06-25

本文共 1614 字，大约阅读时间需要 5 分钟。

最近六级考完，没啥事。刚好有门操作系统课程设计，于是就打开了阔别已久的虚拟机。。。。

#include 
     
      #include 
      
       #include 
       
        #include 
        
         int number=0;             //馆内的人数；int buffer[5]={-1,-1,-1,-1,-1};   //-1代表空座位sem_t sem;                  //信号量pthread_mutex_t mutex;void *thr_fn(void * pth_id){       int chair_id, reader_id;    int time;    reader_id = *(int *)pth_id ;    sleep(1);    pthread_mutex_lock(&mutex);    printf("No.%d Reader  Entered!\n",	reader_id);    number++;    printf("%d people in the reading room...\n",number);    pthread_mutex_unlock(&mutex);            sem_wait(&sem);    for(chair_id = 0;chair_id < 5 ;chair_id++){      if(buffer[chair_id] == -1){	  buffer[chair_id] = reader_id;	  break;	}     }    printf("No.%d Reader  sit at No.%d Seat\n",reader_id,chair_id + 1);    time = rand() % 50;    sleep(time + 3);    printf("No.%d Reader  has been finished reading, Exit!\n",reader_id );    buffer[chair_id] = -1;    sem_post(&sem);    pthread_mutex_lock(&mutex);    number--;    pthread_mutex_unlock(&mutex);        pthread_exit;}int main(void){    int err,t_id,j;    void *pth_id;    pth_id = &t_id;    pthread_t t[10];    pthread_mutex_init(&mutex,NULL);    sem_init(&sem,0,5);    for(t_id = 0; t_id < 10;t_id++){        err=pthread_create(&t[t_id],NULL,thr_fn,pth_id);	  if(err != 0)		printf("ERROR! CREATE THREAD FAILED!!!\n");	  else		printf("No.%d THREAD READY.\n",t_id);        } 　　for(i = 0, i<10, i++) 　　　　pthread_join(t[i],NULL); 　　return 0;}