20 General utilities library [utilities]

20.5 Tuples [tuple]

20.5.3 Class template tuple [tuple.tuple] Tuple traits [tuple.traits]

template<class... Types, class Alloc> struct uses_allocator<tuple<Types...>, Alloc> : true_type { };
Requires: Alloc shall satisfy the Cpp17Allocator requirements ([tab:utilities.allocator.requirements]Table *tab:utilities.allocator.requirements).
Specialization of this trait informs other library components that tuple can be constructed with an allocator, even though it does not have a nested allocator_­type.
end note