In the first recipe of this chapter, we discussed how to work with threads. You also learned that thread functions cannot return values, and threads should use other means, such as shared data, to do so; however, for this, synchronization is required. An alternative to communicating a return value or an exception with either the main or another thread is using std::promise. This recipe will explain how this mechanism works.
Using promises and futures to return values from threads
Getting ready
The promise and future classes used in this recipe are available in the std namespace in the <future> header.
