68 lines
2.1 KiB
C
68 lines
2.1 KiB
C
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/*
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编写一个程序, 创建两个线程, 一个线程负责向共享缓冲区写入数据, 另一个线程负责从缓冲区读取数据。要求实现线程间的同步和互斥, 确保读取线程只能在缓冲区有数据时才能读取, 写入线程只能在缓冲区为空时才能写入。
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【提示】缓冲区可以在main函数中创建char 数组, 并传入到线程中。
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*/
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#include <stdio.h>
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#include <pthread.h>
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#include <unistd.h>
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#include <string.h>
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pthread_rwlock_t rwlock = PTHREAD_RWLOCK_INITIALIZER;
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int buffer_empty = 1; // 缓冲区是否为空的标志，初始为空
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void *w_thread(void *data)
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{
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char *str = (char *)data;
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pthread_rwlock_wrlock(&rwlock); // 获取写入锁
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while (!buffer_empty) // 当缓冲区非空时，释放锁，等待 1 毫秒再次尝试获取写入锁
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{
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pthread_rwlock_unlock(&rwlock); // 释放写入锁
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usleep(1000); // 等待缓冲区为空
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pthread_rwlock_wrlock(&rwlock); // 再次获取写入锁
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}
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printf("请输入内容:");
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fflush(stdout); // 刷新输出缓冲
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scanf("%s", str);
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buffer_empty = 0; // 缓冲区非空
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pthread_rwlock_unlock(&rwlock); // 释放写入锁
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return NULL;
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}
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void *r_thread(void *data)
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{
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char *str = (char *)data;
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pthread_rwlock_rdlock(&rwlock); // 获取读取锁
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while (buffer_empty) // 当缓冲区为空时，释放锁，等待1毫秒缓冲区非空后(等待写缓冲区线程写入内容)，再次获取锁，直到判断非空，在进行后续打印
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{
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pthread_rwlock_unlock(&rwlock); // 释放读取锁
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usleep(1000); // 等待缓冲区非空
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pthread_rwlock_rdlock(&rwlock); // 再次获取读取锁
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}
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printf("输入的内容为: %s\n", str);
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buffer_empty = 1; // 缓冲区为空
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pthread_rwlock_unlock(&rwlock); // 释放读取锁
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return NULL;
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}
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int main(int argc, char const *argv[])
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{
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char str[100];
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pthread_t t1, t2;
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pthread_create(&t1, NULL, w_thread, (void *)str);
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pthread_create(&t2, NULL, r_thread, (void *)str);
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pthread_join(t1, NULL);
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pthread_join(t2, NULL);
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return 0;
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}
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