std::experi...s_swappable,(3)

💖 NAME 💖

hey bestie! welcome to std::experi...s_swappable,(3) from the C++ Standard Libary manual set 💖. this page is serving these trait names:

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

yes, it literally lists std::experimental::ranges::is_swappable_with and std::experimental::ranges::is_swappable twice with a - in the middle, and we are not gonna pretend that’s not a whole vibe 💀

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🦋 Synopsis 🦋

first, here’s the floating line the synopsis starts with:

std::experimental::ranges::is_nothrow_swappable

then it drops the header and declarations like this:

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. (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, it provides the member constant value equal to true. otherwise, value is false. access checks are performed as if from a context unrelated to either type.
2. (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), it provides a member constant value equal to false. otherwise, it provides a member constant value equal to ranges::is_swappable_with<T&, T&>::value.
3. (3) — same as (1), but evaluations of both expressions from (1) are known not to throw exceptions.
4. (4) — same as (2), but uses is_nothrow_swappable_with.

bestie, listen: T and U shall each be a complete type, (possibly cv-qualified) void, or an array of unknown bound. otherwise, the behavior is undefined. not cute, not slay, just undefined 😭

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💅 Member constants 💅

• value — true if T is swappable with U, false otherwise. it’s a [static] public static member constant ✨

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🎀 Member functions 🎀

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

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🌸 Member types 🌸

• value_type — bool
• type — 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. like, the trait can say yes while the actual swap still faceplants 😭

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🍓 Example 🍓

it is literally this, bestie:

This section is incomplete
Reason: no example

no example, just vibes 🙈

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👑 See also 👑

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

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⭐ Category ⭐

• Todo no example

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okay that’s the whole page, bestie 🫶 — it lives at http://cppreference.com, dated 2024.06.10, and it’s std::experi...s_swappable,(3). mwah 💋✨