Why should I use std::async?

Question

I\'m trying to explore all the options of the new C++11 standard in depth, while using std::async and reading its definition, I noticed 2 things, at least under linux with g

Answer 1

If you need the result of an asynchronous operation, then you have to block, no matter what library you use. The idea is that you get to choose when to block, and, hopefully when you do that, you block for a negligible time because all the work has already been done.

Note also that std::async can be launched with policies std::launch::async or std::launch::deferred. If you don't specify it, the implementation is allowed to choose, and it could well choose to use deferred evaluation, which would result in all the work being done when you attempt to get the result from the future, resulting in a longer block. So if you want to make sure that the work is done asynchronously, use std::launch::async.