class template
<future>

std::uses_allocator<promise>

template <class T, class Alloc>  struct uses_allocator<promise<T>,Alloc>;
Uses allocator for promise
This trait specialization of uses_allocator informs that promise objects can be constructed with allocators, even though the class does not have any allocator_type member. It is defined in the <future> with the same behavior as:

1
2
template <class T, class Alloc>
  struct uses_allocator<promise<T>,Alloc> : true_type {};

See also