qfedu-linux-advanced-level/day7/homework/h2_2.c

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

pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
int buffer_empty = 1; // 缓冲区是否为空的标志，初始为空

void *w_thread(void *data)
{
    char *str = (char *)data;

    pthread_mutex_lock(&mutex); // 获取互斥锁

    while (!buffer_empty) // 当缓冲区非空时，等待条件变量被唤醒
    {
        pthread_cond_wait(&cond, &mutex);
    }

    printf("请输入内容:");
    fflush(stdout); // 刷新输出缓冲
    scanf("%s", str);
    buffer_empty = 0; // 缓冲区非空

    pthread_cond_signal(&cond);   // 唤醒等待的读取线程
    pthread_mutex_unlock(&mutex); // 释放互斥锁

    return NULL;
}

void *r_thread(void *data)
{
    char *str = (char *)data;

    pthread_mutex_lock(&mutex); // 获取互斥锁

    while (buffer_empty) // 当缓冲区为空时，等待条件变量被唤醒
    {
        pthread_cond_wait(&cond, &mutex);
    }

    printf("输入的内容为: %s\n", str);
    buffer_empty = 1; // 缓冲区为空

    pthread_cond_signal(&cond);   // 唤醒等待的写入线程
    pthread_mutex_unlock(&mutex); // 释放互斥锁

    return NULL;
}

int main(int argc, char const *argv[])
{
    char str[100];

    pthread_t t1, t2;
    pthread_create(&t1, NULL, w_thread, (void *)str);
    pthread_create(&t2, NULL, r_thread, (void *)str);
    pthread_join(t1, NULL);
    pthread_join(t2, NULL);

    pthread_cond_destroy(&cond);   // 销毁条件变量
    pthread_mutex_destroy(&mutex); // 销毁互斥锁

    return 0;
}