On Sunday, February 15, 2015 11:55 AM, Cheng Mo wrote:
Hi all : I got confused in Doc of boost :: futures and I can't got the point of sort of terms. The represents in Overvies of Futures like " Instances can be freely copied and assigned, and|boost::shared_future<R>::get()| http://www.boost.org/doc/libs/1_57_0/doc/html/thread/synchronization.html#th...returns a non|const|reference so that multiple calls to|boost::shared_future<R>::get()| http://www.boost.org/doc/libs/1_57_0/doc/html/thread/synchronization.html#th...are safe." no doubt that a const reference .... are safe. a non const reference could be changed by external stimuli. isn't ? Or the key is "Instances can be freely copied" , so that we can say "are safe"?
If you click on that link it says: "shared_future<R>::get() returns a const reference to the value stored in the shared state" It's a typo, it should be const&, the contained value is not copied when the shared_future is copied. Ben