20 Memory management library [mem]

20.5 Class template scoped_allocator_adaptor [allocator.adaptor]

20.5.5 Operators [scoped.adaptor.operators]

template<class OuterA1, class OuterA2, class... InnerAllocs>
  bool operator==(const scoped_allocator_adaptor<OuterA1, InnerAllocs...>& a,
                  const scoped_allocator_adaptor<OuterA2, InnerAllocs...>& b) noexcept;

Returns: If sizeof...(InnerAllocs) is zero, a.outer_allocator() == b.outer_allocator() otherwise a.outer_allocator() == b.outer_allocator() && a.inner_allocator() == b.inner_allocator()