生产者消费者模型——信号量

/*
 * 生产者消费者模型
 * 生产者代码实现
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>

#define SHM_SIZE 10            //共享内存大小

void pro_exit(char str[], int temp)        //程序出错，打印错误信息并退出程序
{
    if(temp == -1)
    {
        perror(str);
        exit(0);
    }
}

int main(void)
{
    int        sem_id,                //保存信号量ID
            shm_id;                //保存共享内存ID

    key_t    sem_key,            //保存信号量关键值
            shm_key;            //保存共享内存关键值

    struct sembuf lock0 = {0, -1, 0};        //互拆锁上锁
    struct sembuf unlock0 = {0, 1, 0};        //互拆锁解锁

    struct sembuf lock1 = {1, -1, 0};
    struct sembuf unlock1 = {1, 1, 0};

    struct sembuf lock2 = {2, -1, 0};
    struct sembuf unlock2 = {2, 1, 0};

    int *p;                //指向共享内存
    int ret;
    int n = 100;

    sem_key = ftok("lzy", 2);    //获取互斥锁关键值
    pro_exit("sem_ftok", sem_key);    //检测程序是否出错

    if((sem_id = semget(sem_key, 3, IPC_CREAT |IPC_EXCL | 0666)) < 0)        //创建三个信号量互斥锁
    {
        sem_id = semget(sem_key, 0, 0);        //读取已存在的互斥锁
        pro_exit("semget", sem_id);
    }
    else
    {

    ret = semctl(sem_id, 0, SETVAL, 1);        //设置互斥锁的值为1
    pro_exit("semctl_0", ret);

    ret = semctl(sem_id, 1, SETVAL, 10);    //设置生产者允许生产最大值为30
    pro_exit("semctl_1", ret);

    ret = semctl(sem_id, 2, SETVAL, 0);        //设置消费者允许最小消费
    pro_exit("semctl_2", ret);
    }
    shm_key = ftok("lzy", 1);                //获取共享内存关键值
    pro_exit("shm_ftok", shm_key);            //检测程序是否出错

    shm_id = shmget(shm_key, SHM_SIZE, IPC_CREAT | 0666);    //创建共享内存
    pro_exit("shmget", shm_id);

        p = (int *)shmat(shm_id, NULL, 0);        //映像共享内存
        pro_exit("shmat", (int)*p);

    while(n--)
    {
        semop(sem_id, &lock1, 1);            //生产者上锁
        ret = semop(sem_id, &lock0, 1);            //互斥锁上锁
        pro_exit("semop_lock", ret);


        (*p)++;
        printf("process %d : count = %d\n", getpid(),*p);    //加一



        ret = semop(sem_id, &unlock0, 1);            //互斥锁解锁
        pro_exit("semop_unlock", ret);
        semop(sem_id, &unlock2, 1);                    //消费者加一

        sleep(1);
    }

ret = shmdt(p);                            //释放共享内存
        pro_exit("shmdt", ret);
    ret = shmctl(shm_id, IPC_RMID, NULL);        //删除共享内存
    pro_exit("shmctl", ret);

    ret = semctl(sem_id, 0, IPC_RMID);            //删除信号量
    pro_exit("semctl", ret);

    return 0;
}

/*
 * 生产者消费者模型
 * 消费者代码实现
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>

#define SHM_SIZE 10            //共享内存大小

void pro_exit(char str[], int temp)        //程序出错，打印错误信息并退出程序
{
    if(temp == -1)
    {
        perror(str);
        exit(0);
    }
}

int main(void)
{
    int        sem_id,                //保存信号量ID
            shm_id;                //保存共享内存ID

    key_t    sem_key,            //保存信号量关键值
            shm_key;            //保存共享内存关键值

    struct sembuf lock0 = {0, -1, 0};        //互拆锁上锁
    struct sembuf unlock0 = {0, 1, 0};        //互拆锁解锁

    struct sembuf lock1 = {1, -1, 0};
    struct sembuf unlock1 = {1, 1, 0};

    struct sembuf lock2 = {2, -1, 0};
    struct sembuf unlock2 = {2, 1, 0};

    int *p;                //指向共享内存
    int ret;
    int n = 100;

    sem_key = ftok("lzy", 2);    //获取互斥锁关键值
    pro_exit("sem_ftok", sem_key);    //检测程序是否出错

    if((sem_id = semget(sem_key, 3, IPC_CREAT |IPC_EXCL | 0666)) < 0)        //创建三个信号量互斥锁
    {
        sem_id = semget(sem_key, 0, 0);        //读取已存在的互斥锁
        pro_exit("semget", sem_id);
    }
    else
    {
        ret = semctl(sem_id, 0, SETVAL, 1);        //设置互斥锁的值为1
        pro_exit("semctl_0", ret);

        ret = semctl(sem_id, 1, SETVAL, 10);    //设置生产者允许生产最大值为30
        pro_exit("semctl_1", ret);

        ret = semctl(sem_id, 2, SETVAL, 0);        //设置消费者允许最小消费
        pro_exit("semctl_2", ret);
    }
    shm_key = ftok("lzy", 1);                //获取共享内存关键值
    pro_exit("shm_ftok", shm_key);            //检测程序是否出错

    shm_id = shmget(shm_key, SHM_SIZE, IPC_CREAT | 0666);    //创建共享内存
    pro_exit("shmget", shm_id);

        p = (int *)shmat(shm_id, NULL, 0);        //映像共享内存
        pro_exit("shmat", (int)*p);
    while(n--)
    {
        semop(sem_id, &lock2, 1);            //消费者上锁
        ret = semop(sem_id, &lock0, 1);            //互斥锁上锁
        pro_exit("semop_lock", ret);

        (*p)--;
        printf("ser %d : count = %d\n", getpid(),*p);    //一


        ret = semop(sem_id, &unlock0, 1);            //互斥锁解锁
        pro_exit("semop_unlock", ret);
        semop(sem_id, &unlock1, 1);                    //生产者加一

        sleep(1);
    }

    ret = shmdt(p);                            //释放共享内存
        pro_exit("shmdt", ret);

    ret = shmctl(shm_id, IPC_RMID, NULL);        //删除共享内存
    pro_exit("shmctl", ret);

    ret = semctl(sem_id, 0, IPC_RMID);            //删除信号量
    pro_exit("semctl", ret);

    return 0;
}