std::future does
join without interruption. What does boost::future do? I think it should interrupt and join (or perhaps detach as per N3451).
I don't understand this. Could you clarify?
Sorry, I tried to say too much in one sentence. While std::thread's destructor terminates for joinable thread, std::future's destructor sort-of joins with the (implied) thread: it waits until the job is done. So we already have a potentially surprising suspension upon leaving the scope. I guess this is more acceptable for a higher level abstraction. Now, for boost::future, I could not figure out what it does in the destructor, but if it tries to follow std::future, it probably joins. In the case of the future, interruption appears even more appealing because you join anyway, and you can only speed the waiting up. Then I referred to paper N3451 ("async and ~future"): http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3451.pdf Herb Sutter observes that because future's destructor blocks, the following code: { async( []{ f(); } ); async( []{ g(); } ); } surprisingly, is executed synchronously (i.e., we do not launch the task executing g() until the task executing f() has finished). He proposes a change to std::future to detach in destructor. I just mention it because if boost::future tries to follow std::future, this may become necessary one day. Regards, &rzej