std::clone::Clone - Rust
Description: API documentation for the Rust `Clone` trait in crate `std`.
Keywords: rust, rustlang, rust-lang, Clone

# Trait std::clone::Clone 1.0.0[−][src]

    #[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 `derive`d implementation of `clone` calls `clone` on each field.

## 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 an array holding more than 32 elements of a type that is `Clone`; the standard library only implements `Clone` up until arrays of size 32. In this case, the implementation of `Clone` cannot be `derive`d, but can be implemented as:

    #[derive(Copy)]
    struct Stats {
       frequencies: [i32; 100],
    }

    impl Clone for Stats {
        fn clone(&self) -> Stats { *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

### `
#[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.

## Implementations on Foreign Types

###

`impl Clone for TryFromSliceError`

[src]

####

`fn clone(&self) -> TryFromSliceError`

[src]

####

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

1.0.0
[src]

## Implementors

- `impl<'a> Clone for Chars<'a>` | [src]

- `impl<I> Clone for Cloned<I> where I: Clone,` | [src]

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

- `impl<Y, R> Clone for GeneratorState<Y, R> where R: Clone, Y: Clone,` | [src]

- `impl Clone for ToUppercase` | [src]

- `impl Clone for Utf8Error` | [src]

- `impl<I> Clone for Cycle<I> where I: Clone,` | [src]

- `impl<I, U> Clone for Flatten<I> where I: Iterator + Clone, U: Iterator + Clone, <I as Iterator>::Item: IntoIterator, <<I as Iterator>::Item as IntoIterator>::IntoIter == U, <<I as Iterator>::Item as IntoIterator>::Item == <U as Iterator>::Item,` | [src]

- `impl Clone for EscapeUnicode` | [src]

- `impl<I, F> Clone for FilterMap<I, F> where F: Clone, I: Clone,` | [src]

- `impl Clone for LayoutErr` | [src]

- `impl<I> Clone for StepBy<I> where I: Clone,` | [src]

- `impl<Idx> Clone for std::ops::Range<Idx> where Idx: Clone,` | [src]

- `impl Clone for NonZeroUsize` | [src]

- `impl Clone for usize` | [src]

- `impl Clone for u16` | [src]

- `impl<T> Clone for Bound<T> where T: Clone,` | [src]

- `impl Clone for !` | [src]

- `impl Clone for isize` | [src]

- `impl<Idx> Clone for RangeInclusive<Idx> where Idx: Clone,` | [src]

- `impl Clone for u64` | [src]

- `impl<T, E> Clone for Result<T, E> where E: Clone, T: Clone,` | [src]

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

- `impl<T> Clone for Once<T> where T: Clone,` | [src]

- `impl<Idx> Clone for RangeFrom<Idx> where Idx: Clone,` | [src]

- `impl Clone for CannotReallocInPlace` | [src]

- `impl Clone for Error` | [src]

- `impl<'a> Clone for CharSearcher<'a>` | [src]

- `impl Clone for LocalWaker` | [src]

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

- `impl<T> Clone for *mut T where T: ?Sized,` | [src]

- `impl<A, B> Clone for Zip<A, B> where A: Clone, B: Clone,` | [src]

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

- `impl<A> Clone for std::option::IntoIter<A> where A: Clone,` | [src]

- `impl<A, B> Clone for Chain<A, B> where A: Clone, B: Clone,` | [src]

- `impl Clone for CharTryFromError` | [src]

- `impl<T> Clone for std::result::IntoIter<T> where T: Clone,` | [src]

- `impl Clone for UnicodeVersion` | [src]

- `impl<I, U, F> Clone for FlatMap<I, U, F> where F: Clone, I: Clone, U: Clone + IntoIterator, <U as IntoIterator>::IntoIter: Clone,` | [src]

- `impl Clone for SipHasher` | [src]

- `impl<'a, T> Clone for Chunks<'a, T>` | [src]

- `impl Clone for ParseIntError` | [src]

- `impl Clone for TraitObject` | [src]

- `impl Clone for f32` | [src]

- `impl<'a, P> Clone for std::str::Split<'a, P> where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Clone,` | [src]

- `impl<A> Clone for Repeat<A> where A: Clone,` | [src]

- `impl<I> Clone for DecodeUtf16<I> where I: Clone + Iterator<Item = u16>,` | [src]

- `impl<'a, A> Clone for std::option::Iter<'a, A>` | [src]

- `impl Clone for Pinned` | [src]

- `impl Clone for NonZeroU32` | [src]

- `impl Clone for RangeFull` | [src]

- `impl Clone for FpCategory` | [src]

- `impl Clone for NonZeroU16` | [src]

- `impl<H> Clone for BuildHasherDefault<H>` | [src]

- `impl Clone for NoneError` | [src]

- `impl Clone for i8` | [src]

- `impl<I, P> Clone for SkipWhile<I, P> where I: Clone, P: Clone,` | [src]

- `impl<F> Clone for RepeatWith<F> where F: Clone,` | [src]

- `impl<'a, T, P> Clone for std::slice::Split<'a, T, P> where P: Clone + FnMut(&T) -> bool,` | [src]

- `impl<T> Clone for RefCell<T> where T: Clone,` | [src]

- `impl<'a> Clone for Bytes<'a>` | [src]

- `impl Clone for u8` | [src]

- `impl<I, P> Clone for Filter<I, P> where I: Clone, P: Clone,` | [src]

- `impl Clone for NonZeroU128` | [src]

- `impl<I> Clone for DecodeUtf8<I> where I: Clone + Iterator<Item = u8>,` | [src]

- `impl Clone for EscapeDebug` | [src]

- `impl<'a> Clone for EncodeUtf16<'a>` | [src]

- `impl<T> Clone for PhantomData<T> where T: ?Sized,` | [src]

- `impl<I> Clone for Enumerate<I> where I: Clone,` | [src]

- `impl Clone for Layout` | [src]

- `impl<I, St, F> Clone for Scan<I, St, F> where F: Clone, I: Clone, St: Clone,` | [src]

- `impl<I> Clone for Peekable<I> where I: Clone + Iterator, <I as Iterator>::Item: Clone,` | [src]

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

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

- `impl Clone for Waker` | [src]

- `impl<T> Clone for ManuallyDrop<T> where T: Clone,` | [src]

- `impl Clone for ParseBoolError` | [src]

- `impl<T> Clone for Discriminant<T>` | [src]

- `impl<'a> Clone for Arguments<'a>` | [src]

- `impl Clone for u32` | [src]

- `impl<I> Clone for Take<I> where I: Clone,` | [src]

- `impl<Idx> Clone for RangeTo<Idx> where Idx: Clone,` | [src]

- `impl<T> Clone for Option<T> where T: Clone,` | [src]

- `impl<'a> Clone for SplitWhitespace<'a>` | [src]

- `impl<I, F> Clone for Map<I, F> where F: Clone, I: Clone,` | [src]

- `impl Clone for i128` | [src]

- `impl Clone for i64` | [src]

- `impl<T> Clone for *const T where T: ?Sized,` | [src]

- `impl<'a, 'b> Clone for CharSliceSearcher<'a, 'b>` | [src]

- `impl<'a> Clone for SplitAsciiWhitespace<'a>` | [src]

- `impl<'a, T> Clone for std::result::Iter<'a, T>` | [src]

- `impl Clone for char` | [src]

- `impl Clone for bool` | [src]

- `impl<'a, T> Clone for ExactChunks<'a, T>` | [src]

- `impl Clone for u128` | [src]

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

- `impl Clone for ToLowercase` | [src]

- `impl Clone for ParseFloatError` | [src]

- `impl<I> Clone for Fuse<I> where I: Clone,` | [src]

- `impl Clone for f64` | [src]

- `impl Clone for TryFromIntError` | [src]

- `impl<'a> Clone for Lines<'a>` | [src]

- `impl<'a, T> Clone for std::slice::Iter<'a, T>` | [src]

- `impl Clone for EscapeDefault` | [src]

- `impl<'a> Clone for CharIndices<'a>` | [src]

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

- `impl<I> Clone for Skip<I> where I: Clone,` | [src]

- `impl Clone for Duration` | [src]

- `impl<'a, T> Clone for &'a T where T: ?Sized,` | [src]

- `impl<I, P> Clone for TakeWhile<I, P> where I: Clone, P: Clone,` | [src]

- `impl Clone for NonZeroU64` | [src]

- `impl Clone for i16` | [src]

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

- `impl Clone for NonZeroU8` | [src]

- `impl<T> Clone for Empty<T>` | [src]

- `impl<T> Clone for Rev<T> where T: Clone,` | [src]

- `impl Clone for ParseCharError` | [src]

- `impl<I, F> Clone for Inspect<I, F> where F: Clone, I: Clone,` | [src]

- `impl Clone for i32` | [src]

- `impl<'a, 'b> Clone for StrSearcher<'a, 'b>` | [src]

- `impl<T> Clone for Reverse<T> where T: Clone,` | [src]

- `impl<T> Clone for Wrapping<T> where T: Clone,` | [src]

- `impl Clone for TypeId` | [src]

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

- `impl<T> Clone for Poll<T> where T: Clone,` | [src]

- `impl Clone for AllocErr` | [src]

- `impl<'a, F> Clone for CharPredicateSearcher<'a, F> where F: Clone + FnMut(char) -> bool,` | [src]

- `impl<T> Clone for Cell<T> where T: Copy,` | [src]

- `impl Clone for SearchStep` | [src]

- `impl<Idx> Clone for RangeToInclusive<Idx> where Idx: Clone,` | [src]

- `impl<'a, T, P> Clone for std::slice::RSplit<'a, T, P> where P: Clone + FnMut(&T) -> bool, T: 'a + Clone,` | [src]

- `impl<'a, P> Clone for std::str::RSplit<'a, P> where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: Clone,` | [src]

- `impl<'a> Clone for LinesAny<'a>` | [src]

- `impl<'a, T> Clone for Windows<'a, T>` | [src]

- `impl Clone for DecodeUtf16Error` | [src]

- `impl<T> Clone for NonNull<T> where T: ?Sized,` | [src]

- `impl<'a, T> Clone for std::collections::btree_set::Union<'a, T>` | [src]

- `impl<T> Clone for Box<[T]> where T: Clone,` | [src]

- `impl Clone for String` | [src]

- `impl<T> Clone for Box<T> where T: Clone,` | [src]

- `impl<T> Clone for Arc<T> where T: ?Sized,` | [src]

- `impl<T> Clone for std::vec::IntoIter<T> where T: Clone,` | [src]

- `impl Clone for ParseError` | [src]

- `impl Clone for Global` | [src]

- `impl<'a, K, V> Clone for std::collections::btree_map::Values<'a, K, V>` | [src]

- `impl<'a, T> Clone for std::collections::btree_set::Difference<'a, T>` | [src]

- `impl<'a, K, V> Clone for std::collections::btree_map::Iter<'a, K, V>` | [src]

- `impl<'a, T> Clone for std::collections::btree_set::Iter<'a, T>` | [src]

- `impl<T> Clone for std::collections::linked_list::IntoIter<T> where T: Clone,` | [src]

- `impl<T> Clone for VecDeque<T> where T: Clone,` | [src]

- `impl<'a, B> Clone for Cow<'a, B> where B: ToOwned + ?Sized,` | [src]

- `impl<'a, T> Clone for std::collections::btree_set::Range<'a, T>` | [src]

- `impl<'a, T> Clone for std::collections::btree_set::Intersection<'a, T>` | [src]

- `impl<'a, K, V> Clone for std::collections::btree_map::Keys<'a, K, V>` | [src]

- `impl<'a, T> Clone for std::collections::btree_set::SymmetricDifference<'a, T>` | [src]

- `impl<T> Clone for Vec<T> where T: Clone,` | [src]

- `impl<T> Clone for LinkedList<T> where T: Clone,` | [src]

- `impl<T> Clone for std::collections::vec_deque::IntoIter<T> where T: Clone,` | [src]

- `impl<T> Clone for std::rc::Weak<T> where T: ?Sized,` | [src]

- `impl<'a, T> Clone for std::collections::linked_list::Iter<'a, T>` | [src]

- `impl<T> Clone for std::sync::Weak<T> where T: ?Sized,` | [src]

- `impl<T> Clone for Rc<T> where T: ?Sized,` | [src]

- `impl<T> Clone for BTreeSet<T> where T: Clone,` | [src]

- `impl<'a, T> Clone for std::collections::binary_heap::Iter<'a, T>` | [src]

- `impl<K, V> Clone for BTreeMap<K, V> where K: Clone, V: Clone,` | [src]

- `impl<T> Clone for BinaryHeap<T> where T: Clone,` | [src]

- `impl Clone for CollectionAllocErr` | [src]

- `impl Clone for Box<str>` | [src]

- `impl<T> Clone for std::collections::binary_heap::IntoIter<T> where T: Clone,` | [src]

- `impl<'a, K, V> Clone for std::collections::btree_map::Range<'a, K, V>` | [src]

- `impl<'a, T> Clone for std::collections::vec_deque::Iter<'a, T>` | [src]

- `impl Clone for ThreadId` | [src]

- `impl Clone for Thread` | [src]

- `impl<K: Clone, V: Clone, S: Clone> Clone for HashMap<K, V, S>` | [src]

- `impl<'a, K, V> Clone for std::collections::hash_map::Iter<'a, K, V>` | [src]

- `impl<'a, K, V> Clone for std::collections::hash_map::Keys<'a, K, V>` | [src]

- `impl<'a, K, V> Clone for std::collections::hash_map::Values<'a, K, V>` | [src]

- `impl Clone for RandomState` | [src]

- `impl Clone for DefaultHasher` | [src]

- `impl<T: Clone, S: Clone> Clone for HashSet<T, S>` | [src]

- `impl<'a, K> Clone for std::collections::hash_set::Iter<'a, K>` | [src]

- `impl<'a, T, S> Clone for std::collections::hash_set::Intersection<'a, T, S>` | [src]

- `impl<'a, T, S> Clone for std::collections::hash_set::Difference<'a, T, S>` | [src]

- `impl<'a, T, S> Clone for std::collections::hash_set::SymmetricDifference<'a, T, S>` | [src]

- `impl<'a, T, S> Clone for std::collections::hash_set::Union<'a, T, S>` | [src]

- `impl Clone for VarError` | [src]

- `impl Clone for CString` | [src]

- `impl Clone for NulError` | [src]

- `impl Clone for FromBytesWithNulError` | [src]

- `impl Clone for IntoStringError` | [src]

- `impl Clone for Box<CStr>` | [src]

- `impl Clone for OsString` | [src]

- `impl Clone for Box<OsStr>` | [src]

- `impl Clone for Metadata` | [src]

- `impl Clone for OpenOptions` | [src]

- `impl Clone for Permissions` | [src]

- `impl Clone for FileType` | [src]

- `impl<T: Clone> Clone for Cursor<T>` | [src]

- `impl Clone for ErrorKind` | [src]

- `impl Clone for SeekFrom` | [src]

- `impl Clone for IpAddr` | [src]

- `impl Clone for Ipv6MulticastScope` | [src]

- `impl Clone for Ipv4Addr` | [src]

- `impl Clone for Ipv6Addr` | [src]

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

- `impl Clone for SocketAddrV4` | [src]

- `impl Clone for SocketAddrV6` | [src]

- `impl Clone for AddrParseError` | [src]

- `impl Clone for Shutdown` | [src]

- `impl Clone for stat` | [src]

- `impl<'a> Clone for Prefix<'a>` | [src]

- `impl<'a> Clone for PrefixComponent<'a>` | [src]

- `impl<'a> Clone for Component<'a>` | [src]

- `impl<'a> Clone for Components<'a>` | [src]

- `impl<'a> Clone for std::path::Iter<'a>` | [src]

- `impl<'a> Clone for Ancestors<'a>` | [src]

- `impl Clone for PathBuf` | [src]

- `impl Clone for Box<Path>` | [src]

- `impl Clone for StripPrefixError` | [src]

- `impl Clone for Output` | [src]

- `impl Clone for ExitStatus` | [src]

- `impl Clone for ExitCode` | [src]

- `impl<T: Clone> Clone for SendError<T>` | [src]

- `impl Clone for RecvError` | [src]

- `impl Clone for TryRecvError` | [src]

- `impl Clone for RecvTimeoutError` | [src]

- `impl<T: Clone> Clone for TrySendError<T>` | [src]

- `impl<T> Clone for Sender<T>` | [src]

- `impl<T> Clone for SyncSender<T>` | [src]

- `impl Clone for WaitTimeoutResult` | [src]

- `impl Clone for Instant` | [src]

- `impl Clone for SystemTime` | [src]

- `impl Clone for SystemTimeError` | [src]

- `impl<'a> Clone for EncodeWide<'a>` | [src]

- `impl Clone for std::os::unix::net::SocketAddr` | [src]

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