Johan Torp <johan.torp@gmail.com> writes:
Peter Dimov-5 wrote:
is_ready doesn't trigger the callback, so this won't work.
OTOH, I think is_ready should trigger the callback, even for the "run extra work in wait()" thread pool use case.
ready() should trigger a separate "ready callback", since its semantics are not the same.
(f1 || f2).ready :- f1.ready || f2.ready (f1 || f2).wait :- wait_for_any(f1, f2)
No, (f1 || f2).ready != f1.ready || f2.ready. f1 can be ready and false, in which case we need to wait for f2 to become ready until the composite future is ready.
What does it mean for a shared_future<string> to be "ready and false"? I view "f1 || f2" as a short-hand for a call to wait_for_any(f1,f2) followed by either f1.get() or f2.get() depending on which was ready first.
Java futures don't have this callback proliferation problem because they are abstract.
class future { public: virtual void wait() = 0; virtual bool ready() = 0; };
There are other ways of solving this too, without exposing callbacks.
Can you suggest some? Anthony -- Anthony Williams | Just Software Solutions Ltd Custom Software Development | http://www.justsoftwaresolutions.co.uk Registered in England, Company Number 5478976. Registered Office: 15 Carrallack Mews, St Just, Cornwall, TR19 7UL