写一段操作系统进程通信睡眠的理发师问题的代码

我可以为您提供一个参考解答：

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

#define NUM_CUSTOMERS 10

int waiting_room[NUM_CUSTOMERS];
int num_waiting = 0;

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t barber_cv = PTHREAD_COND_INITIALIZER;
pthread_cond_t customer_cv = PTHREAD_COND_INITIALIZER;

void *barber(void *arg)
{
    while (1) {
        pthread_mutex_lock(&mutex);

        // 如果没有顾客等待，则理发师睡觉
        while (num_waiting == 0) {
            printf("Barber is sleeping...\n");
            pthread_cond_wait(&customer_cv, &mutex);
        }

        // 取出最前面的等待顾客
        int customer = waiting_room[0];

        // 将其他等待顾客往前移动一位
        for (int i = 1; i < num_waiting; i++) {
            waiting_room[i - 1] = waiting_room[i];
        }
        num_waiting--;

        pthread_mutex_unlock(&mutex);

        // 为等待的顾客理发
        printf("Barber is cutting hair for customer %d\n", customer);
        sleep(3); // 理发师理发的时间
        printf("Barber has finished cutting hair for customer %d\n", customer);
    }

    pthread_exit(NULL);
}

void *customer(void *arg)
{
    int id = *(int *)arg;

    pthread_mutex_lock(&mutex);

    // 如果等候室已满，则离开
    if (num_waiting == NUM_CUSTOMERS) {
        printf("Customer %d leaves because waiting room is full\n", id);
        pthread_mutex_unlock(&mutex);
        pthread_exit(NULL);
    }

    // 进入等候室
    waiting_room[num_waiting] = id;
    num_waiting++;

    // 叫醒睡觉的理发师
    pthread_cond_signal(&customer_cv);

    // 等待理发师完成理发
    while (id != waiting_room[0]) {
        printf("Customer %d is waiting...\n", id);
        pthread_cond_wait(&barber_cv, &mutex);
    }

    // 离开理发店
    for (int i = 1; i < num_waiting; i++) {
        waiting_room[i - 1] = waiting_room[i];
    }
    num_waiting--;

    pthread_mutex_unlock(&mutex);

    // 完成理发
    printf("Customer %d has finished cutting hair\n", id);

    pthread_exit(NULL);
}

int main()
{
    pthread_t barber_tid;
    pthread_t customers_tid[NUM_CUSTOMERS];
    int ids[NUM_CUSTOMERS];

    // 创建理发师线程
    pthread_create(&barber_tid, NULL, &barber, NULL);

    // 创建顾客线程
    for (int i = 0; i < NUM_CUSTOMERS; i++) {
        ids[i] = i + 1;
        pthread_create(&customers_tid[i], NULL, &customer, &ids[i]);
        sleep(1); // 创建间隔1秒钟
    }

    // 等待顾客和理发师退出
    for (int i = 0; i < NUM_CUSTOMERS; i++) {
        pthread_join(customers_tid[i], NULL);
    }
    pthread_cancel(barber_tid);
    pthread_join(barber_tid, NULL);

    return 0;
}

这段代码是一个简单的理发师问题的解决方案，利用了 POSIX 线程库的互斥量、条件变量等操作系统进程间通信的机制来协调理发师和顾客任务的执行，并通过睡眠等待的方式实现了进程的挂起和唤醒。