std::experimental::ranges::is_swappable_with, std::experimental::ranges::is_swappable, std::experimental::ranges::is_nothrow_swappable_with, std::experimental::ranges::is_nothrow_swappable
From cppreference.com
| Defined in header <experimental/ranges/type_traits>
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template< class T, class U >
struct is_swappable_with;
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(1) | (ranges TS) |
template< class T >
struct is_swappable;
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(2) | (ranges TS) |
template< class T, class U >
struct is_nothrow_swappable_with;
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(3) | (ranges TS) |
template< class T >
struct is_nothrow_swappable;
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(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.
Contents
Helper variable templates
template< class T, class U >
constexpr bool is_swappable_with_v = is_swappable_with<T, U>::value;
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(1) | (ranges TS) |
template< class T >
constexpr bool is_swappable_v = is_swappable<T>::value;
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(2) | (ranges TS) |
template< class T, class U >
constexpr bool is_nothrow_swappable_with_v = is_nothrow_swappable_with<T, U>::value;
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(3) | (ranges TS) |
template< class T >
constexpr bool is_nothrow_swappable_v = is_nothrow_swappable<T>::value;
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(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
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bool
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type
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std::integral_constant<bool, value>
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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.
Example
| This section is incomplete Reason: no example |
See also
| specifies that a type can be swapped or that two types can be swapped with each other (concept) | |
(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) |