#include <boost/thread.hpp>
#include <boost/thread/barrier.hpp>
#include <boost/chrono.hpp>
#include <iostream>
#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 work" <<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;
}