25 Iterators library [iterators]

25.3 Iterator requirements [iterator.requirements]

25.3.4 Iterator concepts [iterator.concepts] Concept contiguous_iterator [iterator.concept.contiguous]

The contiguous_iterator concept provides a guarantee that the denoted elements are stored contiguously in memory.
template<class I> concept contiguous_iterator = random_access_iterator<I> && derived_from<ITER_CONCEPT(I), contiguous_iterator_tag> && is_lvalue_reference_v<iter_reference_t<I>> && same_as<iter_value_t<I>, remove_cvref_t<iter_reference_t<I>>> && requires(const I& i) { { to_address(i) } -> same_as<add_pointer_t<iter_reference_t<I>>>; };
Let a and b be dereferenceable iterators and c be a non-dereferenceable iterator of type I such that b is reachable from a and c is reachable from b, and let D be iter_difference_t<I>.
The type I models contiguous_iterator only if
  • to_address(a) == addressof(*a),
  • to_address(b) == to_address(a) + D(b - a),
  • to_address(c) == to_address(a) + D(c - a),
  • ranges​::​iter_move(a) has the same type, value category, and effects as std​::​move(*a), and
  • if ranges​::​iter_swap(a, b) is well-formed, it has effects equivalent to ranges​::​swap(*a, *b).