#include <iostream>
#include <boost/thread.hpp>
#include <boost/interprocess/sync/interprocess_semaphore.hpp>

using boost::interprocess::interprocess_semaphore;
using namespace std;

class threadA : public unary_function<shared_ptr<interprocess_semaphore>,void> {
	public:
		void operator ()(shared_ptr<interprocess_semaphore> sem)const
		{
			cout << "a" << endl;
			sem->post();
		}
};

class threadB : public unary_function<shared_ptr<interprocess_semaphore>,void> {
	public:
		void operator ()(shared_ptr<interprocess_semaphore> sem)const
		{
			sem->wait();
			cout << "b" << endl;
		}
};

int main()
{
	using boost::thread;
	shared_ptr<interprocess_semaphore> sem(new interprocess_semaphore(0));
	thread a(threadA(), sem);
	thread b(threadB(), sem);

	a.join();
	b.join();
}