C++ Boost 多线程(八)，条件变量

#include <iostream>
#include <boost/thread.hpp>

using namespace std;

//关联多个线程的条件变量
boost::condition_variable cond;
//保护共享资源的互斥体
boost::mutex mutex;
//共享资源k
int k=0;

void func1(const int &id)
{
	boost::unique_lock<boost::mutex> lock(mutex);
	while(k<5)
	{
		cout<<"thread #"<<id<<" : k<5, waiting..."<<endl;
		cond.wait(lock);
	}
	cout<<"thread #"<<id<<" : now k>5, printing..."<<endl;
}

void func2(const int &id)
{
	boost::unique_lock<boost::mutex> lock(mutex);
	cout<<"thread #"<<id<<" : k will be changed..."<<endl;
	k+=5;
	cond.notify_all();//唤醒所有的等待线程
	cond.notify_one();//只会唤醒一个等待线程
}

int main()
{
	boost::thread t1(func1, 11);
	boost::thread t2(func1, 22);
	boost::thread t3(func2, 33);
	t1.join();
	t2.join();
	t3.join();

	system("pause");
	return 0;
}