----- Original Message ----- From: "Frank Mori Hess" <frank.hess@nist.gov> To: <boost@lists.boost.org> Sent: Thursday, May 15, 2008 3:15 PM Subject: [boost] [future] direct construct from value
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I've just noticed that neither Anthony's or Braddock's future libraries seem to support construction of a future directly from a value, like
future<int> fut_int(5);
Adding such a constructor gives support for implicit conversion of a value of type T to a future<T>. So a function which takes futures as arguments can also seamlessly accept values:
future<void> my_func(future<int> f1, future<int> f2);
my_func(fut_int, 3);
This is important for the usability of poet::active_function, which takes all parameters as futures.
Hello, you can do promise<int> p; future<int> f(p); p.set_value(3); my_func(fut_int, f); which is much more cumberscome. Where do you store the associated promise? Maybe you need a wrapper of a promise and a future that behaves like that that is convertible to a future. template <typename T> struct promise_future { promise_future(T& v) : p_(), f_(p_) { f_.set_value(v); } operator future<T>() { return f_;} promise<T> p_; future<T> f_; } The problem is that yoy have two user conversions, so you will need either promise_future<int> pf(3); my_func(fut_int, pf); or my_func(fut_int, promise_future<int>(3)); Does this works for you? Best Vicente