C++ 11 allows the creation of asynchronous threads using the std:async template function part of the <future> header. The function returns a std::future type that will store the expected return value of std::async’s parameter function. A future is an object that can retrieve a value from some provider object (also known as a promise) or function. Simply put in the case of multithreading, a future object will wait until its associated thread has completed and then store its return value.