20 Memory management library [mem]

20.4 Memory resources [mem.res]

20.4.3 Class template polymorphic_­allocator [mem.poly.allocator.class]

20.4.3.4 Equality [mem.poly.allocator.eq]

template<class T1, class T2> bool operator==(const polymorphic_allocator<T1>& a, const polymorphic_allocator<T2>& b) noexcept;
Returns: *a.resource() == *b.resource().