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std::experimental::ranges::is_swappable_with,std::experimental::ranges::is_swappable,(3) C++ Standard Libary std::experimental::ranges::is_swappable_with,std::experimental::ranges::is_swappable,(3)


std::experimental::ranges::is_swappable_with,std::experimental::ranges::is_swappable, - std::experimental::ranges::is_swappable_with,std::experimental::ranges::is_swappable,



Defined in header <experimental/ranges/type_traits>
template <class T, class U> (1) (ranges TS)
struct is_swappable_with;
template <class T> (2) (ranges TS)
struct is_swappable;
template <class T, class U> (3) (ranges TS)
struct is_nothrow_swappable_with;
template <class T> (4) (ranges TS)
struct is_nothrow_swappable;

1) If the expressions ranges::swap(std::declval<T>(), std::declval<U>()) and
ranges::swap(std::declval<U>(), std::declval<T>()) are both well-formed when treated
as an unevaluated operand, provides the member constant value equal true. Otherwise,
value is false. Access checks are performed as if from a context unrelated to either
2) If T is not a referenceable type (i.e., possibly cv-qualified void or a function
type with a cv-qualifier-seq or a ref-qualifier), provides a member constant value
equal to false. Otherwise, provides a member constant value equal to
ranges::is_swappable_with<T&, T&>::value.
3) Same as (1), but evaluations of both expressions from (1) are known not to throw
4) Same as (2), but uses is_nothrow_swappable_with.

T and U shall each be a complete type, (possibly cv-qualified) void, or an array of
unknown bound. Otherwise, the behavior is undefined.

Helper variable templates

template <class T, class U> (1) (ranges TS)
constexpr bool is_swappable_with_v = is_swappable_with<T, U>::value;
template <class T> (2) (ranges TS)
constexpr bool is_swappable_v = is_swappable<T>::value;
template <class T, class U>
constexpr bool is_nothrow_swappable_with_v = (3) (ranges TS)
is_nothrow_swappable_with<T, U>::value;
template <class T>
constexpr bool is_nothrow_swappable_v = (4) (ranges TS)

Inherited from std::integral_constant

Member constants

value true if T is swappable with U , false otherwise
[static] (public static member constant)

Member functions

operator bool converts the object to bool, returns value
(public member function)
operator() returns value
(C++14) (public member function)

Member types

Type Definition
value_type bool
type std::integral_constant<bool, value>


This trait does not check anything outside the immediate context of the swap
expressions: if the use of T or U would trigger template specializations, generation
of implicitly-defined special member functions etc, and those have errors, the
actual swap may not compile even if ranges::is_swappable_with<T,U>::value compiles
and evaluates to true.


This section is incomplete
Reason: no example

See also

Swappable specifies that a type can be swapped or that two types can
SwappableWith be swapped with each other
is_nothrow_swappable_with checks if objects of a type can be swapped with objects of
is_nothrow_swappable same or different type
(C++17) (class template)