iter_move(std::common_iterator)

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Iterator library

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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)

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std::common_iterator

Member functions
common_iterator::common_iterator
common_iterator::operator=
common_iterator::operator*common_iterator::operator->
common_iterator::operator++common_iterator::operator++(int)
Non-member functions
operator== (C++20)
operator- (C++20)
iter_move (C++20)
iter_swap (C++20)
Helper classes
incrementable_traits<std::common_iterator> (C++20)
iterator_traits<std::common_iterator> (C++20)

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friendconstexpr decltype(auto) iter_move(conststd::common_iterator& i) noexcept(noexcept(ranges::iter_move(std::declval<const I&>())) requiresstd::input_iterator<I>;		(since C++20)

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

The function body is equivalent to:return std::ranges::iter_move(std::get<I>(i.var));.

This function is not visible to ordinaryunqualified orqualified lookup, and can only be found byargument-dependent lookup whenstd::common_iterator<I, S> is an associated class of the arguments.

Ifi.var does not hold anI object (i.e. an iterator), the behavior is undefined.

[edit]Parameters

a source iterator adaptor

[edit]Return value

An rvalue reference or a prvalue temporary.

[edit]Complexity

Constant.

[edit]Example

Run this code

#include <iomanip>#include <iostream>#include <iterator>#include <string>#include <vector> void print(autoconst& rem,autoconst& v){std::cout<< rem<<'['<< size(v)<<"] { ";for(int o{};autoconst& s: v)std::cout<<(o++?", ":"")<<std::quoted(s);std::cout<<" }\n";} int main(){std::vector<std::string> p{"Andromeda","Cassiopeia","Phoenix"}, q;    print("p", p);    print("q", q); using CTI=std::counted_iterator<std::vector<std::string>::iterator>;using CI=std::common_iterator<CTI,std::default_sentinel_t>;    CI last{std::default_sentinel}; for(CI first{{p.begin(),2}}; first!= last;++first)        q.emplace_back(/* ADL */ iter_move(first));     print("p", p);    print("q", q);}

Possible output:

p[3] { "Andromeda", "Cassiopeia", "Phoenix" }q[0] {  }p[3] { "", "", "Phoenix" }q[2] { "Andromeda", "Cassiopeia" }

[edit]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 wasstd::iter_rvalue_reference_t<I>	changed todecltype(auto)

[edit]See also

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