[span.syn]

# 23 Containers library [[containers]](./#containers)

## 23.7 Views [[views]](views#span.syn)

### 23.7.2 Contiguous access [[views.contiguous]](views.contiguous#span.syn)

#### 23.7.2.1 Header <span> synopsis [span.syn]

[🔗](#header:%3cspan%3e)

#include <initializer_list> // see [[initializer.list.syn]](initializer.list.syn "17.11.2 Header <initializer_­list> synopsis")// mostly freestandingnamespace std {// constantsinline constexpr size_t [dynamic_extent](#lib:dynamic_extent "23.7.2.1 Header <span> synopsis [span.syn]") = numeric_limits<size_t>::max(); template<class T>concept [*integral-constant-like*](#concept:integral-constant-like "23.7.2.1 Header <span> synopsis [span.syn]") = // *exposition only* is_integral_v<remove_cvref_t<decltype(T::value)>> &&!is_same_v<bool, remove_const_t<decltype(T::value)>> &&[convertible_to](concept.convertible#concept:convertible_to "18.4.4 Concept convertible_­to [concept.convertible]")<T, decltype(T::value)> &&[equality_comparable_with](concept.equalitycomparable#concept:equality_comparable_with "18.5.4 Concept equality_­comparable [concept.equalitycomparable]")<T, decltype(T::value)> && bool_constant<T() == T::value>::value && bool_constant<static_cast<decltype(T::value)>(T()) == T::value>::value; template<class T>constexpr size_t [*maybe-static-ext*](#concept:maybe-static-ext "23.7.2.1 Header <span> synopsis [span.syn]") = dynamic_extent; // *exposition only*template<[*integral-constant-like*](#concept:integral-constant-like "23.7.2.1 Header <span> synopsis [span.syn]") T>constexpr size_t [*maybe-static-ext*](#concept:maybe-static-ext "23.7.2.1 Header <span> synopsis [span.syn]")<T> = {T::value}; // [[views.span]](views.span "23.7.2.2 Class template span"), class template spantemplate<class ElementType, size_t Extent = dynamic_extent>class span; // partially freestandingtemplate<class ElementType, size_t Extent>constexpr bool ranges::enable_view<span<ElementType, Extent>> = true; template<class ElementType, size_t Extent>constexpr bool ranges::enable_borrowed_range<span<ElementType, Extent>> = true; // [[span.objectrep]](span.objectrep "23.7.2.3 Views of object representation"), views of object representationtemplate<class ElementType, size_t Extent> span<const byte, Extent == dynamic_extent ? dynamic_extent : sizeof(ElementType) * Extent> as_bytes(span<ElementType, Extent> s) noexcept; template<class ElementType, size_t Extent> span<byte, Extent == dynamic_extent ? dynamic_extent : sizeof(ElementType) * Extent> as_writable_bytes(span<ElementType, Extent> s) noexcept;}