std::experimental::promise (library fundamentals TS)
From cppreference.com
                    
                                        
                    < cpp | experimental | lib extensions
                    
                                                            
                    | Defined in header  <experimental/future> | ||
| template< class R > class promise; | (1) | (library fundamentals TS) | 
| template< class R > class promise<R&>; | (2) | (library fundamentals TS) | 
| template<>          class promise<void>; | (3) | (library fundamentals TS) | 
std::experimental::fundamentals_v1::promise (and std::experimental::fundamentals_v2::promise) is a modified version of std::promise provided by the library fundamentals TS with support for type-erased allocators.
| Contents | 
[edit] Member types
| Member type | Definition | 
| allocator_type | std::experimental::erased_type | 
[edit] Member functions
| constructs the promise object (public member function) | |
| retrieves a pointer to the memory resource used by this object to allocate memory (public member function) | 
[edit] Non-member function
| specializes the swapalgorithm(function template) | 
[edit] Helper classes
| specializes the std::uses_allocator type trait (class template specialization) |