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Trait std::clone::Clone

#[lang = "clone"]pub trait Clone {
#[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,
}

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
    }
}

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

`#[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());

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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.

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Implementations on Foreign Types

`impl Clone for __m256i`[src]

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

`impl Clone for __m64`[src]

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

`impl Clone for __m128`[src]

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

`impl Clone for __m128d`[src]

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

`impl Clone for __m512i`[src]

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

`impl Clone for __m512`[src]

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

`impl<'a, P> Clone for SplitInclusive<'a, P> where P: Pattern<'a>, >::Searcher: Clone,` [src]

fn clone(&self) -> SplitInclusive<'a, P>ⓘNotable traits for SplitInclusive<'a, P>
impl<'a, P> Iterator for SplitInclusive<'a, P> where
    P: Pattern<'a>, 
    type Item = &'a str;

Trait std::clone::Clone

Derivable

How can I implement Clone?

Additional implementors

Required methods

#[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 __m256i[src]

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

impl Clone for __m64[src]

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

impl Clone for __m128[src]

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

impl Clone for __m128d[src]

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

impl Clone for __m512i[src]

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

impl Clone for __m512[src]

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

impl<'a, P> Clone for SplitInclusive<'a, P> where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Clone, [src]

fn clone(&self) -> SplitInclusive<'a, P>ⓘNotable traits for SplitInclusive<'a, P> impl<'a, P> Iterator for SplitInclusive<'a, P> where P: Pattern<'a>, type Item = &'a str; [src]

Notable traits for SplitInclusive<'a, P>

impl Clone for __m256d[src]

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

impl Clone for CpuidResult[src]

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

impl Clone for __m128i[src]

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

impl Clone for __m256[src]

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

impl Clone for __m512d[src]

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

impl<'_, T, P> Clone for SplitInclusive<'_, T, P> where P: Clone + FnMut(&T) -> bool, [src]

fn clone(&self) -> SplitInclusive<'_, T, P>ⓘNotable traits for SplitInclusive<'a, T, P> impl<'a, T, P> Iterator for SplitInclusive<'a, T, P> where P: FnMut(&T) -> bool, type Item = &'a [T]; [src]

Notable traits for SplitInclusive<'a, T, P>

Implementors

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

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

impl Clone for TryReserveError[src]

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

impl Clone for Infallible[src]

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

impl Clone for VarError[src]

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

impl Clone for ErrorKind[src]

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

impl Clone for SeekFrom[src]

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

impl Clone for IpAddr[src]

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

impl Clone for Ipv6MulticastScope[src]

fn clone(&self) -> Ipv6MulticastScope[src]

impl Clone for Shutdown[src]

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

impl Clone for std::net::SocketAddr[src]

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

impl Clone for FpCategory[src]

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

impl Clone for IntErrorKind[src]

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

impl Clone for SearchStep[src]

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

impl Clone for std::sync::atomic::Ordering[src]

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

impl Clone for RecvTimeoutError[src]

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

impl Clone for TryRecvError[src]

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

impl Clone for bool[src]

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

impl Clone for char[src]

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

impl Clone for f32[src]

fn clone(&self) -> f32[src]

impl Clone for f64[src]

fn clone(&self) -> f64[src]

impl Clone for i8[src]

How can I implement `Clone`?

`#[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 __m256i`[src]

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

`impl Clone for __m64`[src]

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

`impl Clone for __m128`[src]

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

`impl Clone for __m128d`[src]

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

`impl Clone for __m512i`[src]

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

`impl Clone for __m512`[src]

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

`impl<'a, P> Clone for SplitInclusive<'a, P> where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Clone,` [src]

`fn clone(&self) -> SplitInclusive<'a, P>ⓘNotable traits for SplitInclusive<'a, P> impl<'a, P> Iterator for SplitInclusive<'a, P> where P: Pattern<'a>, type Item = &'a str;`[src]

`impl Clone for __m256d`[src]

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

`impl Clone for CpuidResult`[src]

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

`impl Clone for __m128i`[src]

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

`impl Clone for __m256`[src]

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

`impl Clone for __m512d`[src]

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

`impl<'_, T, P> Clone for SplitInclusive<'_, T, P> where P: Clone + FnMut(&T) -> bool,` [src]

`fn clone(&self) -> SplitInclusive<'_, T, P>ⓘNotable traits for SplitInclusive<'a, T, P> impl<'a, T, P> Iterator for SplitInclusive<'a, T, P> where P: FnMut(&T) -> bool, type Item = &'a [T];`[src]

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

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

`impl Clone for TryReserveError`[src]

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

`impl Clone for Infallible`[src]

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

`impl Clone for VarError`[src]

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

`impl Clone for ErrorKind`[src]

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

`impl Clone for SeekFrom`[src]

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

`impl Clone for IpAddr`[src]

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

`impl Clone for Ipv6MulticastScope`[src]

`fn clone(&self) -> Ipv6MulticastScope`[src]

`impl Clone for Shutdown`[src]

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

`impl Clone for std::net::SocketAddr`[src]

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

`impl Clone for FpCategory`[src]

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

`impl Clone for IntErrorKind`[src]

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

`impl Clone for SearchStep`[src]

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

`impl Clone for std::sync::atomic::Ordering`[src]

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

`impl Clone for RecvTimeoutError`[src]

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

`impl Clone for TryRecvError`[src]

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

`impl Clone for bool`[src]

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

`impl Clone for char`[src]

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

`impl Clone for f32`[src]

`fn clone(&self) -> f32`[src]

`impl Clone for f64`[src]

`fn clone(&self) -> f64`[src]

`impl Clone for i8`[src]

`fn clone(&self) -> i8`[src]

`impl Clone for i16`[src]

`fn clone(&self) -> i16`[src]

`impl Clone for i32`[src]

`fn clone(&self) -> i32`[src]

`impl Clone for i64`[src]

`fn clone(&self) -> i64`[src]

`impl Clone for i128`[src]

`fn clone(&self) -> i128`[src]

`impl Clone for isize`[src]