std::ranges::iter_move(3) C++ Standard Libary std::ranges::iter_move(3) NAME std::ranges::iter_move - std::ranges::iter_move Synopsis Defined in header <iterator> inline namespace /* unspecified */ { inline constexpr /* unspecified */ iter_move = /* (since C++20) unspecified */; (customization point object) } Call signature template< class T > requires /* see below */ (since C++20) constexpr decltype(auto) iter_move( T&& t ) noexcept(/* see below */); Obtains an rvalue reference or a prvalue temporary from a given itera- tor. A ranges::iter_move(t) is expression-equivalent to: 1. iter_move(t), if t has a class or enumeration type and the expres- sion is well-formed when treated as an unevaluated operand, where the over- load resolution of iter_move is performed only with the candidates found by argument-dependent lookup. 2. Otherwise, std::move(*t) if *t is well-formed and is an lvalue. 3. Otherwise, *t if *t is well-formed and is an rvalue. In all other cases, a call to ranges::iter_move is ill-formed, which can result in substitution failure when ranges::iter_move(e) appears in the immediate context of a template instantiation. If ranges::iter_move(e) is not equal to *e, the program is ill-formed, no diagnostic required. Customization point objects The name ranges::iter_move denotes a customization point object, which is a const function object of a literal semiregular class type. For exposition pur- poses, the cv-unqualified version of its type is denoted as __iter_move_fn. All instances of __iter_move_fn are equal. The effects of invoking dif- ferent instances of type __iter_move_fn on the same arguments are equivalent, regardless of whether the expression denoting the instance is an lvalue or rvalue, and is const-qualified or not (however, a volatile-qualified instance is not required to be invocable). Thus, ranges::iter_move can be copied freely and its copies can be used interchangeably. Given a set of types Args..., if std::declval<Args>()... meet the re- quirements for arguments to ranges::iter_move above, __iter_move_fn models * std::invocable<__iter_move_fn, Args...>, * std::invocable<const __iter_move_fn, Args...>, * std::invocable<__iter_move_fn&, Args...>, and * std::invocable<const __iter_move_fn&, Args...>. Otherwise, no function call operator of __iter_move_fn participates in overload resolution. Example This section is incomplete Reason: no example See also iter_move casts the result of dereferencing the adjusted underlying it- erator to its (C++20) associated rvalue reference type (function) iter_move casts the result of dereferencing the underlying iterator to its (C++20) associated rvalue reference type (function) Category: * Todo no example http://cppreference.com 2024.06.10 std::ranges::iter_move(3)
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