#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 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;

}