#include<iostream>
#include<boost/chrono.hpp>
#include<boost/thread.hpp>
#include<boost/thread/barrier.hpp>
#include<cstdlib>
#include<ctime>

using namespace std;

void worker(int id, boost::barrier &sync_point)
	{
	 cout<<"thread : "<<id<<" entering work "<<endl;
	 boost::this_thread::sleep_for(boost::chrono::milliseconds(500));
	 sync_point.wait();
	 cout<<"Thread: "<< id <<" leaving barrier"<<endl;
	}

int main() {
	srand(time(0));
	int num_threads=rand()%6+3;
	cout << "Creating: "<<num_threads <<endl;
	boost::barrier sync_point(num_threads);
	 

	boost::thread_group tg;
	for (int i=0; i<num_threads; i++)
	  {
	   tg.create_thread(boost::bind(worker,i,boost::ref(sync_point))); 
  	  }
	tg.join_all();
	return 0;
	
}