#define BOOST_THREAD_PROVIDES_FUTURE
#define BOOST_THREAD_PROVIDES_FUTURE_CONTINUATION

#include <boost/thread/future.hpp>

int main(int argc, char const *argv[])
{
    boost::promise<int> prom;
    boost::future<int> futr = prom.get_future();

    int callCount = 0;

    auto futr2 = futr.then(boost::launch::deferred,
        [&] (boost::future<int> f) {
            callCount++;
            assert(f.valid());
            assert(f.is_ready());
            if (f.is_ready()) {
                assert(17 == f.get());
            }
        });

    assert(futr2.valid());
    assert(!futr2.is_ready());
    assert(0 == callCount);

    prom.set_value(17);
    assert(1 == callCount);

    futr2.get();
    assert(1 == callCount);

    futr2.get();
    assert(1 == callCount);
    /* code */
    return 0;
}