class template
<future>

std::uses_allocator<packaged_task>

template <class Ret, class Alloc>  struct uses_allocator<packaged_task<Ret>,Alloc>;
Uses allocator for packaged_task
This trait specialization of uses_allocator informs that packaged_task 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:

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template <class Ret, class Alloc>
  struct uses_allocator<packaged_task<Ret>,Alloc> : true_type {};

See also