生产者与消费者

来源：互联网发布：ovs linux网桥编辑：程序博客网时间：2024/05/22 05:00
#include <stdio.h>#include <string.h>#include <unistd.h>#include <pthread.h>#include <sys/types.h>#include <time.h>#include <fcntl.h>#include <semaphore.h>#include <sys/ipc.h>#include <errno.h>#define MYFIFO "myfifo"#define BUFFER_SIZE 3#define UNIT_SIZE 5#define RUN_TIME 30#define DELAY_TIME_LEVELS 5.0void *producer(void *arg);void *customer(void *arg);int fd;time_t end_time;sem_t mutex,full,avail;int main(){    int ret;    pthread_t thrd_prd_id,thrd_cst_id;    srand(time(NULL));    end_time = time(NULL) + RUN_TIME;        /*创建有名管道*/    if((mkfifo(MYFIFO,0644) < 0) && (errno != EEXIST))    {        perror("mkfifo error!");        exit(-1);    }        /*打开管道*/    fd = open(MYFIFO,O_RDWR);    if(fd == -1)    {        perror("open fifo error");        exit(-1);    }        /*初始化互斥信号量为1*/    ret = sem_init(&mutex,0,1);        /*初始化avail信号量为 N */    ret += sem_init(&avail,0,BUFFER_SIZE);    /*初始化full信号量为0*/    ret += sem_init(&full,0,0);    if(ret != 0)    {        perror("sem_init error");        exit(-1);    }        /*创建两个线程*/    ret = pthread_create(&thrd_prd_id,NULL,producer,NULL);    if(ret != 0)    {        perror("producer pthread_create error");        exit(-1);    }    ret = pthread_create(&thrd_cst_id,NULL,customer,NULL);    if(ret != 0)    {        perror("customer pthread_create error");        exit(-1);    }    pthread_join(thrd_prd_id,NULL);    pthread_join(thrd_cst_id,NULL);    close(fd);    unlink(MYFIFO);    return 0;}void *producer(void *arg) //生产者线程{    int real_write;    int delay_time;    while(time(NULL) < end_time)    {        delay_time = (int)(rand() * DELAY_TIME_LEVELS/RAND_MAX/2.0) + 1;        sleep(delay_time);                /*P操作信号量avail和mutex*/        sem_wait(&avail);        sem_wait(&mutex);        printf("\nproducer have delayed %d seconds\n",delay_time);                /*生产者写入数据*/        if((real_write = write(fd,"hello",UNIT_SIZE)) == -1)        {            if(errno == EAGAIN)            {                printf("The buffer is full,please wait for reading!\n");            }        }        else        {            printf("producer writes %d bytes to the FIFO\n",real_write);                    printf("Now,the buffer left %d spaces!\n",avail);        }                /*V操作信号量full 和 mutex*/        sem_post(&full);        sem_post(&mutex);    }    pthread_exit(NULL);}void *customer(void *arg) //消费者线程{    unsigned char read_buffer[UNIT_SIZE];    int real_read;    int delay_time;    while(time(NULL) < end_time)    {        delay_time = (int)(rand() * DELAY_TIME_LEVELS/RAND_MAX/2.0) + 1;        sleep(delay_time);        sem_wait(&full); //P操作信号量full和mutex        sem_wait(&mutex);        memset(read_buffer,0,UNIT_SIZE);        printf("\nCustomer have delayed %d seconds\n",delay_time);        if((real_read = read(fd,read_buffer,UNIT_SIZE)) == -1)        {            if(errno == EAGAIN)            {                printf("The buffer is empty,please wait for writing!\n");            }        }        else        {            printf("customer reads %d bytes from the FIFO\n",real_read);                }        sem_post(&avail); //V操作信号量 avail 和 mutex        sem_post(&mutex);           }    pthread_exit(NULL);}
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