线程同步——条件变量

来源：互联网发布：hadoop数据目录配置编辑：程序博客网时间：2024/04/30 12:32
多线程中条件变量的使用：
// 线程同步之条件变量#include <iostream>#include <string>#include <unistd.h>#include <stdlib.h>#include <stdio.h>#include <string.h>#include <pthread.h>#include <semaphore.h>using namespace std;// 一个简单的缓冲区类struct SimpleBuffer{    static const int buffer_size = 8;    int buffer[8];    int pos;    SimpleBuffer()    {        memset(buffer,0,sizeof(int) * 64);        pos = -1;    }    bool Full()    {        if(pos == buffer_size - 1)        {            return true;        }        return false;    }    bool Empty()    {        if(pos == -1)            return true;        return false;    }    bool Push(int data)    {        if(pos == buffer_size - 1)            return false;        buffer[++pos] = data;        return true;    }    bool Pop(int& data)    {        if(pos == -1)            return false;        data = buffer[pos--];        return true;    }};// 公共缓冲区，给生产者和消费者读写SimpleBuffer common_buffer;//  条件变量// 缓冲区未满条件变量pthread_cond_t cond_buffer_not_full;// 缓冲区不为空条件变量pthread_cond_t cond_buffer_not_empty;// 缓冲区锁pthread_mutex_t buffer_lock;// 生产者线程void* producer(void* data){    int count = 0;    while(count < 64)    {        ++count;        // 加锁        pthread_mutex_lock(&buffer_lock);        // 等待缓冲区不满        while (common_buffer.Full()) {            pthread_cond_wait(&cond_buffer_not_full,&buffer_lock);        }        // 往缓冲区中添加数据        common_buffer.Push(count);        // 通知消费者，缓冲区不为空        pthread_cond_signal(&cond_buffer_not_empty);        // 解锁        pthread_mutex_unlock(&buffer_lock);        sleep(1);    }}// 消费者线程void* consumer(void* data){    int count = 0;    while(count < 64)    {        // 加锁        pthread_mutex_lock(&buffer_lock);        // 等待缓冲区不为空        while(common_buffer.Empty())        {            pthread_cond_wait(&cond_buffer_not_empty,&buffer_lock);        }        // 从缓冲区中消耗数据        int data;        common_buffer.Pop(data);        cout << data << endl;        // 通知生产者，缓冲区不满        pthread_cond_signal(&cond_buffer_not_full);        // 解锁        pthread_mutex_unlock(&buffer_lock);        ++count;    }}// 主函数int main(int argc,char* argv[]){    // 初始化缓冲区锁    pthread_mutex_init(&buffer_lock,0);    // 初始化两个条件变量    pthread_cond_init(&cond_buffer_not_empty,0);    pthread_cond_init(&cond_buffer_not_full,0);    // 定义两个线程id    pthread_t thd1,thd2;    // 创建生产者和消费者线程    pthread_create(&thd1,0,consumer,0);    pthread_create(&thd2,0,producer,0);    // 等待两个线程运行结束    pthread_join(thd1,0);    pthread_join(thd2,0);    // 销毁锁和条件变量    pthread_cond_destroy(&cond_buffer_not_full);    pthread_cond_destroy(&cond_buffer_not_empty);    pthread_mutex_destroy(&buffer_lock);    return  0;}
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