iter_move(std::counted_iterator)

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Diagnostics library

Memory management library

Metaprogramming library (C++11)

General utilities library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library (C++17)

Concurrency support library (C++11)

Execution control library (C++26)

Technical specifications

Symbols index

External libraries

 

Iterator library

Iterator concepts
indirectly_readable (C++20) indirectly_writable (C++20) weakly_incrementable (C++20) incrementable (C++20) is-integer-like is-signed-integer-like (C++20)(C++20)	sentinel_for (C++20) sized_sentinel_for (C++20) input_iterator (C++20) output_iterator (C++20) input_or_output_iterator (C++20)	forward_iterator (C++20) bidirectional_iterator (C++20) random_access_iterator (C++20) contiguous_iterator (C++20)
Iterator primitives
input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tagcontiguous_iterator_tag (C++20)	iter_value_titer_difference_titer_reference_titer_const_reference_titer_rvalue_reference_titer_common_reference_t (C++20)(C++20)(C++20)(C++23)(C++20)(C++20)	iterator (deprecated in C++17) iterator_traits incrementable_traits (C++20) indirectly_readable_traits (C++20)
Algorithm concepts and utilities
Indirect callable concepts
indirectly_unary_invocableindirectly_regular_unary_invocable (C++20)(C++20)	indirect_unary_predicate (C++20) indirect_binary_predicate (C++20)	indirect_equivalence_relation (C++20) indirect_strict_weak_order (C++20)
Common algorithm requirements
indirectly_movable (C++20) indirectly_movable_storable (C++20) indirectly_copyable (C++20)	indirectly_copyable_storable (C++20)   indirectly_swappable (C++20) indirectly_comparable (C++20)	permutable (C++20) mergeable (C++20) sortable (C++20)
Utilities
indirect_result_t (C++20)	projected (C++20)	projected_value_t (C++26)
Iterator adaptors
reverse_iterator make_reverse_iterator (C++14) move_iterator (C++11) make_move_iterator (C++11) default_sentinel_tdefault_sentinel (C++20)(C++20) unreachable_sentinel_tunreachable_sentinel (C++20)(C++20)	front_insert_iterator back_insert_iterator inserter insert_iterator front_inserter back_inserter move_sentinel (C++20)	common_iterator (C++20) counted_iterator (C++20) basic_const_iterator (C++23) const_iterator (C++23) const_sentinel (C++23) make_const_iterator (C++23) make_const_sentinel (C++23)
Stream iterators istream_iterator    ostream_iterator istreambuf_iterator ostreambuf_iterator	Iterator customization points ranges::iter_move (C++20) ranges::iter_swap (C++20)
Iterator operations advance distance prev (C++11)   next (C++11) ranges::advance (C++20) ranges::distance (C++20) ranges::prev (C++20) ranges::next (C++20)	Range access begincbegin (C++11)(C++14) rbegincrbegin (C++14)(C++14)   endcend (C++11)(C++14) rendcrend (C++14)(C++14)   sizessize (C++17)(C++20) empty (C++17) data (C++17)

 

std::counted_iterator

Member functions

counted_iterator::counted_iterator

counted_iterator::operator=

counted_iterator::base

counted_iterator::count

counted_iterator::operator*counted_iterator::operator->

counted_iterator::operator[]

counted_iterator::operator++counted_iterator::operator++(int)counted_iterator::operator+counted_iterator::operator+=counted_iterator::operator--counted_iterator::operator--(int)counted_iterator::operator-counted_iterator::operator-=

Non-member functions

operator==operator<=> (C++20)(C++20)

operator==(default_sentinel_t) (C++20)

operator+ (C++20)

operator- (C++20)

operator-(default_sentinel_t) (C++20)

iter_move (C++20)

iter_swap (C++20)

Helper classes

iterator_traits<std::counted_iterator> (C++20)

 

friend constexpr decltype(auto) iter_move( const std::counted_iterator& i ) noexcept(noexcept(ranges::iter_move(i.base()))) requires std::input_iterator<I>;		(since C++20)

Casts the result of dereferencing the underlying iterator to its associated rvalue reference type.

Equivalent to return ranges::iter_move(i.base());.

If i.count() > 0 is false, the behavior is undefined.	(until C++26)
If i.count() > 0 is false: If the implementation is hardened, a contract violation occurs. If the implementation is not hardened, the behavior is undefined.	(since C++26)

This function is not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when std::counted_iterator<I> is an associated class of the arguments.

Parameters

i

-

a source iterator adaptor

Return value

An rvalue reference or a prvalue temporary.

Complexity

Constant.

Example

Run this code

#include <iomanip>
#include <iostream>
#include <iterator>
#include <string>
#include <vector>

void print(const auto& rem, const auto& v)
{
    std::cout << rem << '[' << size(v) << "] {";
    for (char comma[]{0, ' ', 0}; const auto& s : v)
        std::cout << comma << std::quoted(s), *comma = ',';
    std::cout << "}\n";
}

int main()
{
    std::vector<std::string> p{"Alpha", "Bravo", "Charlie"}, q;
    print("p", p);
    print("q", q);
    
    using RI = std::counted_iterator<std::vector<std::string>::iterator>;
    
    for (RI iter{p.begin(), 2}; iter != std::default_sentinel; ++iter)
        q.emplace_back(/* ADL */ iter_move(iter));
    
    print("p", p);
    print("q", q);
}

Possible output:

p[3] {"Alpha", "Bravo", "Charlie"}
q[0] {}
p[3] {"", "", "Charlie"}
q[2] {"Alpha", "Bravo"}

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 3953	C++20	the return type was std::iter_rvalue_reference_t<I>	changed to decltype(auto)

See also

iter_move (C++20)	casts the result of dereferencing an object to its associated rvalue reference type (customization point object)
iter_swap (C++20)	swaps the objects pointed to by two underlying iterators (function template)
move (C++11)	converts the argument to an xvalue (function template)
move_if_noexcept (C++11)	converts the argument to an xvalue if the move constructor does not throw (function template)
forward (C++11)	forwards a function argument and use the type template argument to preserve its value category (function template)
ranges::move (C++20)	moves a range of elements to a new location (algorithm function object)
ranges::move_backward (C++20)	moves a range of elements to a new location in backwards order (algorithm function object)