3144. span does not have a const_pointer typedef

Section: 23.7.2.2.1 [span.overview] Status: C++20 Submitter: Louis Dionne Opened: 2018-07-23 Last modified: 2021-02-25

Priority: 0

View all other issues in [span.overview].

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Discussion:

std::span does not have a typedef for const_pointer and const_reference. According to Marshall Clow, this is merely an oversight.

[2019-01-20 Reflector prioritization]

Set Priority to 0 and status to Tentatively Ready

Proposed resolution:

This wording is relative to N4750.

1. Change 23.7.2.2.1 [span.overview], class template span synopsis, as indicated:

   namespace std {
     template<class ElementType, ptrdiff_t Extent = dynamic_extent>
     class span {
     public:
       // constants and types
       using element_type = ElementType;
       using value_type = remove_cv_t<ElementType>;
       using index_type = ptrdiff_t;
       using difference_type = ptrdiff_t;
       using pointer = element_type*;
       using const_pointer = const element_type*;
       using reference = element_type&;
       using const_reference = const element_type&;
       using iterator = implementation-defined;
       using const_iterator = implementation-defined;
       using reverse_iterator = reverse_iterator<iterator>;
       using const_reverse_iterator = reverse_iterator<const_iterator>;
       static constexpr index_type extent = Extent;
     
       […]
     };
     […]
   }