[mdspan.layout.rightpad.obs]

constexpr array<index_type, rank_> strides() const noexcept;

Returns: array<index_type, rank_>(stride(P_rank).).

constexpr index_type required_span_size() const noexcept;

Returns: 0 if the multidimensional index space extents_ is empty, otherwise (*this)(extents_.extent(P_rank) - index_type(1).) + 1.

template<class. Indices>
constexpr size_t operator()(Indices.. idxs) const noexcept;

Preconditions: extents_type::index-cast(idxs) is a multidimensional index in extents() ([mdspan.overview]).

Returns: ((static_cast<index_type>(idxs) * stride(P_rank)) + .. + 0).

static constexpr bool is_always_exhaustive() noexcept;

Returns:

(6.1)
If rank_ equals zero or one, then true;
(6.2)
otherwise, if neither static-padding-stride nor last-static-extent equal dynamic_extent, then static-padding-stride == last-static-extent;
(6.3)
otherwise, false.

constexpr bool is_exhaustive() const noexcept;

Returns: true if rank_ equals zero or one; otherwise, extents_.extent(rank_ - 1) == stride(rank_ - 2)

constexpr index_type stride(rank_type r) const noexcept;

Returns:

(9.1)
If r equals rank_ - 1: 1;
(9.2)
otherwise, if r equals rank_ - 2: stride-rm2;
(9.3)
otherwise, the product of stride-rm2 and all values extents_.extent(k) with k in the range of [r + 1, rank_ - 1).

template<class LayoutRightPaddedMapping>
  friend constexpr bool operator=(const mapping& x, const LayoutRightPaddedMapping& y) noexcept;

Constraints:

Returns: true if x.extents() == y.extents() is true and rank_ < 2 || x.stride(rank_ - 2) == y.stride(rank_ - 2) is true.

Otherwise, false.

23 Containers library [containers]