FreeBSD Manual Pages
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*/; (customiza- tion point object) } Call signature template< class T > requires /* see below */ constexpr decltype(auto) iter_move( T&& t ) noexcept(/* see below */); Obtains an rvalue reference or a prvalue temporary from a given it- erator. A call to ranges::iter_move is expression-equivalent to: 1. iter_move(std::forward<T>(t)), if std::remove_cvref_t<T> is a class or enumeration type and the expression is well-formed in unevalu- ated context, where the overload resolution is performed with the following candi- dates: * void iter_move(); * any declarations of iter_move found by argument-dependent lookup. 2. Otherwise, std::move(*std::forward<T>(t)) if *std::forward<T>(t) is well-formed and is an lvalue. 3. Otherwise, *std::forward<T>(t) if *std::forward<T>(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 imme- diate context of a template instantiation. If ranges::iter_move(e) is not equal to *e, the program is ill- formed, no diagnostic required. Expression-equivalent Expression e is expression-equivalent to expression f, if * e and f have the same effects, and * either both are constant subexpressions or else neither is a constant subexpression, and * either both are potentially-throwing or else neither is poten- tially-throwing (i.e. noexcept(e) == noexcept(f)). 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 purposes, 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 different instances of type __iter_move_fn on the same arguments are equiva- lent, 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 requirements 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. See also iter_move casts the result of dereferencing the adjusted underlying iterator 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) http://cppreference.com 2022.07.31 std::ranges::iter_move(3)
NAME | Synopsis | rvalue. | See also
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=std::ranges::iter_move&sektion=3&manpath=FreeBSD+Ports+15.0>