多线程同步

标签：linux c   linux编程   多线程程序设计   多线程同步   linux多线程   

1.多个线程按照规定的顺序来执行，即线程同步

2.条件变量实现线程同步

 初始化：      pthread_cond_t cond_ready = PTHREAD_COND_INITIALIZER;
 等待条件成熟：pthread_cond_wait(&cond_ready,&mut);
 设置成熟条件：pthread_cond_signal(&cond_ready);

3.综合实例

/***********************************************************************
 * file_name:   sync.c
 * Description: A先扫完5次地后B拖一次地
 ***********************************************************************/
	
#include <stdio.h>
#include <pthread.h>

pthread_t thread[2];
int number = 0;
pthread_mutex_t mut;
pthread_cond_t cond_ready =  PTHREAD_COND_INITIALIZER;

void studentA()
{
	int i;
	
	for(i=0; i<5; i++)
	{
		pthread_mutex_lock(&mut);
		//扫一次地
		number++;
		
		if(number>=5)
		{
			printf("student A has finished his work !\n");
			//通知B同学
			pthread_cond_signal(&cond_ready);
		}
		pthread_mutex_unlock(&mut);
		
		//休息1秒钟
		sleep(1);
	}
	//退出
	pthread_exit(NULL);
}

void studentB()
{
	pthread_mutex_lock(&mut);
	
	if(number<5)
	{
		//等待A的唤醒,此函数会自动上锁
		pthread_cond_wait(&cond_ready,&mut);
	}
	number = 0;
	pthread_mutex_unlock(&mut);
	printf("student B has finished his work !\n");
	//退出
	pthread_exit(NULL);
}

int main()
{
	//初始化互斥锁
	pthread_mutex_init(&mut,NULL);
	
	//创建A同学线程
	pthread_create(&thread[0],NULL,studentA,NULL);
	
	//创建B同学线程
	pthread_create(&thread[1],NULL,studentB,NULL);
	
	//等待A同学线程结束
	pthread_join(thread[0],NULL);
	
	//等待B同学线程结束
	pthread_join(thread[1],NULL);
}

多线程同步

标签：linux c   linux编程   多线程程序设计   多线程同步   linux多线程   

原文地址：http://blog.csdn.net/zhuwenfeng215/article/details/45565369