1.0.0[−][src]Trait std::clone::Clone

[+] Show declaration

[+] Expand attributes
#[lang = "clone"]
pub trait Clone {
[+] Expand attributes
#[must_use = "cloning is often expensive and is not expected to have side effects"]
    fn clone(&self) -> Self;

    fn clone_from(&mut self, source: &Self) { ... }
}

[−]

A common trait for the ability to explicitly duplicate an object.

Differs from Copy in that Copy is implicit and extremely inexpensive, while Clone is always explicit and may or may not be expensive. In order to enforce these characteristics, Rust does not allow you to reimplement Copy, but you may reimplement Clone and run arbitrary code.

Since Clone is more general than Copy, you can automatically make anything Copy be Clone as well.

Derivable

This trait can be used with #[derive] if all fields are Clone. The derived implementation of clone calls clone on each field.

For a generic struct, #[derive] implements Clone conditionally by adding bound Clone on generic parameters.

// `derive` implements Clone for Reading<T> when T is Clone.
#[derive(Clone)]
struct Reading<T> {
    frequency: T,
}Run

How can I implement `Clone`?

Types that are Copy should have a trivial implementation of Clone. More formally: if T: Copy, x: T, and y: &T, then let x = y.clone(); is equivalent to let x = *y;. Manual implementations should be careful to uphold this invariant; however, unsafe code must not rely on it to ensure memory safety.

An example is a generic struct holding a function pointer. In this case, the implementation of Clone cannot be derived, but can be implemented as:

struct Generate<T>(fn() -> T);

impl<T> Copy for Generate<T> {}

impl<T> Clone for Generate<T> {
    fn clone(&self) -> Self {
        *self
    }
}Run

Additional implementors

In addition to the implementors listed below, the following types also implement Clone:

Function item types (i.e., the distinct types defined for each function)
Function pointer types (e.g., fn() -> i32)
Array types, for all sizes, if the item type also implements Clone (e.g., [i32; 123456])
Tuple types, if each component also implements Clone (e.g., (), (i32, bool))
Closure types, if they capture no value from the environment or if all such captured values implement Clone themselves. Note that variables captured by shared reference always implement Clone (even if the referent doesn't), while variables captured by mutable reference never implement Clone.

Required methods

`[+] Expand attributes #[must_use = "cloning is often expensive and is not expected to have side effects"] fn clone(&self) -> Self`[−]

Returns a copy of the value.

Examples

let hello = "Hello"; // &str implements Clone

assert_eq!("Hello", hello.clone());Run

Provided methods

`fn clone_from(&mut self, source: &Self)`[−]

Performs copy-assignment from source.

a.clone_from(&b) is equivalent to a = b.clone() in functionality, but can be overridden to reuse the resources of a to avoid unnecessary allocations.

1.0.0[−][src]Trait std::clone::Clone

Derivable

How can I implement Clone?

Additional implementors

Required methods

[+] Expand attributes#[must_use = "cloning is often expensive and is not expected to have side effects"] fn clone(&self) -> Self[−]

Examples

Provided methods

fn clone_from(&mut self, source: &Self)[−]

Implementations on Foreign Types

impl Clone for __m128[src][−]

fn clone(&self) -> __m128[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for __m128d[src][−]

fn clone(&self) -> __m128d[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for __m256d[src][−]

fn clone(&self) -> __m256d[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for __m64[src][−]

fn clone(&self) -> __m64[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for __m256[src][−]

fn clone(&self) -> __m256[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for __m512[src][−]

fn clone(&self) -> __m512[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for __m512d[src][−]

fn clone(&self) -> __m512d[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for CpuidResult[src][−]

fn clone(&self) -> CpuidResult[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for __m128i[src][−]

fn clone(&self) -> __m128i[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for __m256i[src][−]

fn clone(&self) -> __m256i[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for __m512i[src][−]

fn clone(&self) -> __m512i[src]

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl<K, V, S> Clone for HashMap<K, V, S> where K: Clone, S: Clone, V: Clone, [−]

fn clone(&self) -> HashMap<K, V, S>

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl Clone for CollectionAllocErr[−]

fn clone(&self) -> CollectionAllocErr

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl<'_, T, S> Clone for Union<'_, T, S>[−]

ⓘImportant traits for Union<'a, T, S>Important traits for Union<'a, T, S>impl<'a, T, S> Iterator for Union<'a, T, S> where S: BuildHasher, T: Eq + Hash, type Item = &'a T;fn clone(&self) -> Union<'_, T, S>

Important traits for Union<'a, T, S>

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl<'_, K, V> Clone for Keys<'_, K, V>[−]

ⓘImportant traits for Keys<'a, K, V>Important traits for Keys<'a, K, V>impl<'a, K, V> Iterator for Keys<'a, K, V> type Item = &'a K;fn clone(&self) -> Keys<'_, K, V>

Important traits for Keys<'a, K, V>

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl<'_, K, V> Clone for Iter<'_, K, V>[−]

ⓘImportant traits for Iter<'a, K, V>Important traits for Iter<'a, K, V>impl<'a, K, V> Iterator for Iter<'a, K, V> type Item = (&'a K, &'a V);fn clone(&self) -> Iter<'_, K, V>

Important traits for Iter<'a, K, V>

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl<'_, T, S> Clone for Difference<'_, T, S>[−]

ⓘImportant traits for Difference<'a, T, S>Important traits for Difference<'a, T, S>impl<'a, T, S> Iterator for Difference<'a, T, S> where S: BuildHasher, T: Eq + Hash, type Item = &'a T;fn clone(&self) -> Difference<'_, T, S>

Important traits for Difference<'a, T, S>

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl<T, S> Clone for HashSet<T, S> where S: Clone, T: Clone, [−]

fn clone(&self) -> HashSet<T, S>

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl<'_, T, S> Clone for SymmetricDifference<'_, T, S>[−]

ⓘImportant traits for SymmetricDifference<'a, T, S>Important traits for SymmetricDifference<'a, T, S>impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S> where S: BuildHasher, T: Eq + Hash, type Item = &'a T;fn clone(&self) -> SymmetricDifference<'_, T, S>

Important traits for SymmetricDifference<'a, T, S>

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl<'_, K> Clone for Iter<'_, K>[−]

ⓘImportant traits for Iter<'a, K>Important traits for Iter<'a, K>impl<'a, K> Iterator for Iter<'a, K> type Item = &'a K;fn clone(&self) -> Iter<'_, K>

Important traits for Iter<'a, K>

fn clone_from(&mut self, source: &Self)1.0.0[src]

impl<'_, T, S> Clone for Intersection<'_, T, S>[−]

ⓘImportant traits for Intersection<'a, T, S>Important traits for Intersection<'a, T, S>impl<'a, T, S> Iterator for Intersection<'a, T, S> where S: BuildHasher, T: Eq + Hash, type Item = &'a T;fn clone(&self) -> Intersection<'_, T, S>

Important traits for Intersection<'a, T, S>

fn clone_from(&mut self, source: &Self)1.0.0[src]

How can I implement `Clone`?

`[+] Expand attributes #[must_use = "cloning is often expensive and is not expected to have side effects"] fn clone(&self) -> Self`[−]

`fn clone_from(&mut self, source: &Self)`[−]

`impl Clone for __m128`[src][−]

`fn clone(&self) -> __m128`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for __m128d`[src][−]

`fn clone(&self) -> __m128d`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for __m256d`[src][−]

`fn clone(&self) -> __m256d`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for __m64`[src][−]

`fn clone(&self) -> __m64`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for __m256`[src][−]

`fn clone(&self) -> __m256`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for __m512`[src][−]

`fn clone(&self) -> __m512`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for __m512d`[src][−]

`fn clone(&self) -> __m512d`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for CpuidResult`[src][−]

`fn clone(&self) -> CpuidResult`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for __m128i`[src][−]

`fn clone(&self) -> __m128i`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for __m256i`[src][−]

`fn clone(&self) -> __m256i`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for __m512i`[src][−]

`fn clone(&self) -> __m512i`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl<K, V, S> Clone for HashMap<K, V, S> where K: Clone, S: Clone, V: Clone,` [−]

`fn clone(&self) -> HashMap<K, V, S>`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for CollectionAllocErr`[−]

`fn clone(&self) -> CollectionAllocErr`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl<'_, T, S> Clone for Union<'_, T, S>`[−]

ⓘImportant traits for Union<'a, T, S>
Important traits for Union<'a, T, S>
`impl<'a, T, S> Iterator for Union<'a, T, S> where S: BuildHasher, T: Eq + Hash, type Item = &'a T;`
`fn clone(&self) -> Union<'_, T, S>`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl<'_, K, V> Clone for Keys<'_, K, V>`[−]

ⓘImportant traits for Keys<'a, K, V>
Important traits for Keys<'a, K, V>
`impl<'a, K, V> Iterator for Keys<'a, K, V> type Item = &'a K;`
`fn clone(&self) -> Keys<'_, K, V>`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl<'_, K, V> Clone for Iter<'_, K, V>`[−]

ⓘImportant traits for Iter<'a, K, V>
Important traits for Iter<'a, K, V>
`impl<'a, K, V> Iterator for Iter<'a, K, V> type Item = (&'a K, &'a V);`
`fn clone(&self) -> Iter<'_, K, V>`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl<'_, T, S> Clone for Difference<'_, T, S>`[−]

ⓘImportant traits for Difference<'a, T, S>
Important traits for Difference<'a, T, S>
`impl<'a, T, S> Iterator for Difference<'a, T, S> where S: BuildHasher, T: Eq + Hash, type Item = &'a T;`
`fn clone(&self) -> Difference<'_, T, S>`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl<T, S> Clone for HashSet<T, S> where S: Clone, T: Clone,` [−]

`fn clone(&self) -> HashSet<T, S>`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl<'_, T, S> Clone for SymmetricDifference<'_, T, S>`[−]

ⓘImportant traits for SymmetricDifference<'a, T, S>
Important traits for SymmetricDifference<'a, T, S>
`impl<'a, T, S> Iterator for SymmetricDifference<'a, T, S> where S: BuildHasher, T: Eq + Hash, type Item = &'a T;`
`fn clone(&self) -> SymmetricDifference<'_, T, S>`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl<'_, K> Clone for Iter<'_, K>`[−]

ⓘImportant traits for Iter<'a, K>
Important traits for Iter<'a, K>
`impl<'a, K> Iterator for Iter<'a, K> type Item = &'a K;`
`fn clone(&self) -> Iter<'_, K>`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl<'_, T, S> Clone for Intersection<'_, T, S>`[−]

ⓘImportant traits for Intersection<'a, T, S>
Important traits for Intersection<'a, T, S>
`impl<'a, T, S> Iterator for Intersection<'a, T, S> where S: BuildHasher, T: Eq + Hash, type Item = &'a T;`
`fn clone(&self) -> Intersection<'_, T, S>`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl<'_, K, V> Clone for Values<'_, K, V>`[−]

ⓘImportant traits for Values<'a, K, V>
Important traits for Values<'a, K, V>
`impl<'a, K, V> Iterator for Values<'a, K, V> type Item = &'a V;`
`fn clone(&self) -> Values<'_, K, V>`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for TryDemangleError`[−]

`fn clone(&self) -> TryDemangleError`

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for std::cmp::Ordering`[src][−]

`fn clone(&self) -> Ordering`[src]

`fn clone_from(&mut self, source: &Self)`[src]

`impl Clone for std::collections::CollectionAllocErr`[src][−]

`fn clone(&self) -> CollectionAllocErr`[src]

`fn clone_from(&mut self, source: &Self)`1.0.0[src]

`impl Clone for Infallible`[src][−]

`fn clone(&self) -> Infallible`[src]