mutiple threads----condition variable

reference:http://www.cplusplus.com/reference/condition_variable/condition_variable/

A condition variable is an object able to block the calling thread until notified to resume

It uses a unique_lock (over a mutex) to lock the thread when one of its wait functions is called. The thread remains blocked until woken up by another thread that calls a notification function on the same condition_variable object.

#include<iostream>
#include<vector>
#include<algorithm>
#include<mutex>
#include<condition_variable>

using namespace std;

mutex mu;
condition_variable cond;
bool ready = false;



void thread_wait(int id) {

	unique_lock<mutex> locker(mu);
	while (!ready) {
		cond.wait(locker);
	}

	cout << "thread " << id << endl;
}

void go() {
	unique_lock<mutex> locker(mu);
	ready = true;
	cond.notify_all();
}

int main() {

	thread threads[10];

	for (int i = 0; i < 10; i++)
	{
		threads[i] = thread(thread_wait, i);
	}
	go();


	for (auto & th : threads) {
		th.join();
	}
	getchar();
	return 0;
}