FreeBSD Manual Pages
std::ranges::iter_swap(3) C++ Standard Libary std::ranges::iter_swap(3) NAME std::ranges::iter_swap - std::ranges::iter_swap Synopsis Defined in header <iterator> namespace ranges { inline namespace /*unspecified*/ { inline constexpr /*unspecified*/ iter_swap = (since C++20) /*unspecified*/; (customiza- tion point object) } } Call signature template< class I1, class I2 > constexpr void iter_swap( I1&& i1, I2&& i2 ) (since C++20) noexcept(/* see below */); Swaps values denoted by two iterators. ranges::iter_swap(i1, i2 is expression-equivalent to: 1. (void)iter_swap(i1, i2), if std::remove_cvref_t<I1> or std::re- move_cvref_t<I2> is a class or enumeration type and the expression is well- formed, where the overload resolution is performed within namespace std::ranges with the additional candidate: * void iter_swap(auto, auto) = delete; If the selected overload does not exchange the value denoted by i1 and i2, the program is ill-formed, no diagnostic required. 2. Otherwise, ranges::swap(*i1, *i2) if both I1 and I2 model indi- rectly_readable and if std::iter_reference_t<I1> and std::iter_reference_t<I2> model swappable_with. 3. Otherwise, (void)(*i1 = /*iter_exchange_move*/(i2, i1)), if std::indirectly_movable_storable<I1, I2> and std::indirectly_movable_storable<I2, I1>, where iter_ex- change_move is an exposition-only function template described below (and i1 is only evaluated once). 4. Otherwise, ranges::iter_swap(i1, i2) is ill-formed, which can result in substitution failure when ranges::iter_swap(e1, e2) appears in the immediate context of a template instantiation. The exposition-only function template iter_exchange_move is defined the equivalent of: template<class X, class Y> constexpr std::iter_value_t<X> /*iter_exchange_move*/(X&& x, Y&& y) noexcept(noexcept(std::iter_value_t<X>(std::ranges::iter_move(x)) && noexcept(*x = std::ranges::iter_move(y)))) { std::iter_value_t<X> old(std::ranges::iter_move(x)); *x = std::ranges::iter_move(y); return old; } 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_swap 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_swap_fn. All instances of __iter_swap_fn are equal. The effects of invoking different instances of type __iter_swap_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_swap 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_swap above, __iter_swap_fn models * std::invocable<__iter_swap_fn, Args...>, * std::invocable<const __iter_swap_fn, Args...>, * std::invocable<__iter_swap_fn&, Args...>, and * std::invocable<const __iter_swap_fn&, Args...>. Otherwise, no function call operator of __iter_swap_fn participates in overload resolution. See also iter_swap swaps the objects pointed to by two adjusted underlying iterators (C++20) (function template) iter_swap swaps the objects pointed to by two underlying iterators (C++20) (function template) iter_swap swaps the elements pointed to by two iterators (function template) http://cppreference.com 2022.07.31 std::ranges::iter_swap(3)
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=std::ranges::iter_swap&sektion=3&manpath=FreeBSD+Ports+15.0>