std::experimental::ranges::is_swappable_with, std::experimental::ranges::is_swappable, std::experimental::ranges::is_nothrow_swappable_with, std::experimental::ranges::is_nothrow_swappable

 

C++

Language

Standard Library Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals 2 TS)

Extensions for parallelism (parallelism TS)

Extensions for parallelism 2 (parallelism TS v2)

Extensions for concurrency (concurrency TS)

Concepts (concepts TS)

Ranges (ranges TS)

Special mathematical functions (special math TR)

 

Ranges

Concepts

General utilities

Iterators

Ranges

Algorithms

 

General utilities library

Utility components
swap	exchange
Function objects
invoke identity	equal_to not_equal_to	greater less	greater_equal less_equal
Metaprogramming and type traits
is_swappable_withis_swappable	is_nothrow_swappable_withis_nothrow_swappable	common_reference common_type
Tagged pairs and tuples
TagSpecifier TaggedType	tagged tag specifiers	tagged_pair make_tagged_pair	tagged_tuple make_tagged_tuple

 

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

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 type.

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 exceptions.

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

Inherited from std::integral_constant

Member constants

value [static]

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

Member functions

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

Member types

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

Notes

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.

See also

SwappableSwappableWith	specifies that a type can be swapped or that two types can be swapped with each other (concept)
is_swappable_withis_swappableis_nothrow_swappable_withis_nothrow_swappable (C++17)(C++17)(C++17)(C++17)	checks if objects of a type can be swapped with objects of same or different type (class template)