std::input_iterator(3) | C++ Standard Libary | std::input_iterator(3) |
NAME¶
std::input_iterator - std::input_iterator
Synopsis¶
Defined in header <iterator>
template<class I>
concept input_iterator =
std::input_or_output_iterator<I> && (since C++20)
std::indirectly_readable<I> &&
requires { typename /*ITER_CONCEPT*/<I>; } &&
std::derived_from</*ITER_CONCEPT*/<I>,
std::input_iterator_tag>;
The input_iterator concept is a refinement of input_or_output_iterator,
adding the
requirement that the referenced values can be read (via indirectly_readable)
and the
requirement that the iterator concept tag be present.
Iterator concept determination
Definition of this concept is specified via an exposition-only alias template
/*ITER_CONCEPT*/.
In order to determine /*ITER_CONCEPT*/<I>, let ITER_TRAITS<I>
denote I if the
specialization std::iterator_traits<I> is generated from the primary
template, or
std::iterator_traits<I> otherwise:
* If ITER_TRAITS<I>::iterator_concept is valid and names a type,
/*ITER_CONCEPT*/<I> denotes the type.
* Otherwise, if ITER_TRAITS<I>::iterator_category is valid and names a
type,
/*ITER_CONCEPT*/<I> denotes the type.
* Otherwise, if std::iterator_traits<I> is generated from the primary
template,
/*ITER_CONCEPT*/<I> denotes std::random_access_iterator_tag.
* Otherwise, /*ITER_CONCEPT*/<I> does not denote a type and results in
a
substitution failure.
Notes¶
Unlike the LegacyInputIterator requirements, the input_iterator
concept does not
require equality_comparable, since input iterators are typically compared
with
sentinels.
See also¶
input_or_output_iterator specifies that objects of a type can be
incremented and
(C++20) dereferenced
(concept)
2022.07.31 | http://cppreference.com |