std::readable_traits (3) - Linux Man Pages

std::readable_traits: std::readable_traits

NAME

std::readable_traits - std::readable_traits

Synopsis


Defined in header <iterator>
template< class I > (1) (since C++20)
struct readable_traits { };
template< class T > (2) (since C++20)
struct readable_traits<T*>;
template< class I >
requires std::is_array_v<I> (3) (since C++20)
struct readable_traits<I>;
template< class T > (4) (since C++20)
struct readable_traits<const T> : value_type<T> { };
template <class T>
requires requires { typename T::value_type; } (5) (since C++20)
struct readable_traits<T>;
template <class T>
requires requires { typename T::element_type; } (6) (since C++20)
struct readable_traits<T>;


Computes the associated value type of the type I, if any. Users may specialize readable_traits for a program-defined type.
1) Primary template is an empty struct.
2) Specialization for pointers. If T is an object type, provides a member type value_type equal to std::remove_cv_t<T>. Otherwise, there is no member value_type.
3) Specialization for array types. Provides a member type value_type equal to std::remove_cv_t<std::remove_extent_t<I>>.
4) Specialization for const-qualified types.
5) Specialization for types that define a public and accessible member type value_type. If T::value_type is an object type, provides a member type value_type equal to std::remove_cv_t<typename T::value_type>. Otherwise, there is no member value_type.
6) Specialization for types that define a public and accessible member type element_type (e.g., std::shared_ptr). If T::element_type is an object type, provides a member type value_type equal to std::remove_cv_t<typename T::element_type>. Otherwise, there is no member value_type.

Notes


If a type contains both a value_type member and a element_type member, then the specializations (5) and (6) are ambiguous.
value_type is intended for use with Readable types such as iterators. It is not intended for use with ranges.

Example


 This section is incomplete
 Reason: no example

See also


                        specifies that a type is readable by applying operator *
Readable (concept)


iter_value_t
iter_reference_t computes the associate types of an iterator
iter_difference_t (alias template)
iter_rvalue_reference_t
iter_common_reference_t
                        provides uniform interface to the properties of an iterator
iterator_traits (class template)