std::uses_allocator<std::packaged_task>
From cppreference.com
                    
                                        
                    < cpp | thread | packaged task
                    
                                                            
                    |   template< class R, class Alloc > struct uses_allocator<std::packaged_task<R>, Alloc> : true_type {};  | 
 (since C++11)  (removed in C++17)  | 
|
Provides a specialization of the std::uses_allocator type trait for std::packaged_task.
Inherited from std::integral_constant
Member constants
|    value [static]  | 
   true   (public static member constant)  | 
Member functions
|    operator bool  | 
   converts the object to bool, returns value   (public member function)  | 
|    operator() (C++14)  | 
   returns value   (public member function)  | 
Member types
| Type | Definition | 
  value_type
 | 
bool | 
  type
 | 
std::integral_constant<bool, value> | 
See also
|    (C++11)  | 
  checks if the specified type supports uses-allocator construction  (class template)  |