{

{

boost::mutex mtx;

boost::strict_lock<boost::mutex> lk(mtx);

std::cout << __FILE__ << std::endl;

}

{

boost::timed_mutex mtx;

boost::unique_lock<boost::timed_mutex> lk(mtx);

boost::nested_strict_lock<boost::unique_lock<boost::timed_mutex> > nlk(lk);

std::cout << __FILE__ << std::endl;

}

{

boost::mutex mtx;

boost::unique_lock<boost::mutex> lk(mtx, boost::defer_lock);

boost::nested_strict_lock<boost::unique_lock<boost::mutex> > nlk(lk);

std::cout << __FILE__ << std::endl;

}

return 0;