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

http://www.cplusplus.com/reference/future/async/

there are three type of policy,

1. launch::async
2. launch::deferred
3. launch::async|launch::deferred

by default launch::async|launch::deferred is passed to std::async.