Trait std::clone::Clone

#[lang = "clone"]
pub trait Clone {
    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.

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 derived, but can be implemented as:

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

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

Required Methods

fn clone(&self) -> Self

Returns a copy of the value.

Examples

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

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

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 StandardNormal

fn clone(&self) -> StandardNormal

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

impl Clone for LogNormal

fn clone(&self) -> LogNormal

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

impl Clone for IsaacRng

fn clone(&self) -> IsaacRng

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

impl Clone for Isaac64Rng

fn clone(&self) -> Isaac64Rng

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

impl Clone for XorShiftRng

fn clone(&self) -> XorShiftRng

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

impl Clone for Exp

fn clone(&self) -> Exp

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

impl Clone for ReseedWithDefault

fn clone(&self) -> ReseedWithDefault

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

impl Clone for ChaChaRng

fn clone(&self) -> ChaChaRng

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

impl Clone for Normal

fn clone(&self) -> Normal

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

impl Clone for Exp1

fn clone(&self) -> Exp1

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

impl Clone for _Unwind_Action

fn clone(&self) -> _Unwind_Action

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

impl Clone for _Unwind_Reason_Code

fn clone(&self) -> _Unwind_Reason_Code

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

impl<I> Clone for Utf16Encoder<I> where
    I: Clone, 

fn clone(&self) -> Utf16Encoder<I>

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

impl<T> Clone for NonZero<T> where
    T: Zeroable + Clone, 

fn clone(&self) -> NonZero<T>

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

impl Clone for timeval

fn clone(&self) -> timeval

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

impl Clone for timespec

fn clone(&self) -> timespec

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

impl Clone for stat

fn clone(&self) -> stat

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

impl Clone for utimbuf

fn clone(&self) -> utimbuf

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

impl Clone for tm

fn clone(&self) -> tm

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

Implementors

• impl Clone for DecodeUtf16Error
• impl<'a> Clone for SplitWhitespace<'a>
• impl<I> Clone for DecodeUtf16<I> where
    I: Clone + Iterator<Item = u16>, 
• impl<A, B> Clone for Zip<A, B> where
    A: Clone,
    B: Clone, 
• impl<I> Clone for Enumerate<I> where
    I: Clone, 
• impl<'a, 'b> Clone for StrSearcher<'a, 'b>
• impl Clone for FpCategory
• impl<'a, 'b> Clone for CharSliceSearcher<'a, 'b>
• impl<'a, T> Clone for std::result::Iter<'a, T>
• impl Clone for Error
• impl<I, F> Clone for Inspect<I, F> where
    F: Clone,
    I: Clone, 
• impl<I, St, F> Clone for Scan<I, St, F> where
    F: Clone,
    I: Clone,
    St: Clone, 
• impl<'a, T> Clone for Chunks<'a, T>
• impl Clone for EscapeDebug
• impl<T> Clone for Discriminant<T>
• impl<T> Clone for Option<T> where
    T: Clone, 
• impl<'a> Clone for Lines<'a>
• impl<A, B> Clone for Chain<A, B> where
    A: Clone,
    B: Clone, 
• impl<T, E> Clone for Result<T, E> where
    E: Clone,
    T: Clone, 
• impl<I> Clone for StepBy<I> where
    I: Clone, 
• impl<'a, T> Clone for Windows<'a, T>
• impl<T> Clone for Unique<T> where
    T: ?Sized, 
• impl Clone for TryFromIntError
• impl<I, F> Clone for FilterMap<I, F> where
    F: Clone,
    I: Clone, 
• impl<T> Clone for Cell<T> where
    T: Copy, 
• impl Clone for TypeId
• impl Clone for std::cmp::Ordering
• impl<I> Clone for Peekable<I> where
    I: Clone + Iterator,
    <I as Iterator>::Item: Clone, 
• impl<T> Clone for PhantomData<T> where
    T: ?Sized, 
• impl<I> Clone for Cycle<I> where
    I: Clone, 
• impl<T> Clone for Shared<T> where
    T: ?Sized, 
• impl<'a, T> Clone for std::slice::Iter<'a, T>
• impl Clone for ParseCharError
• impl<'a, P> Clone for RMatchIndices<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl Clone for TraitObject
• impl<'a> Clone for Chars<'a>
• impl<Idx> Clone for std::ops::Range<Idx> where
    Idx: Clone, 
• impl<'a, F> Clone for CharPredicateSearcher<'a, F> where
    F: Clone + FnMut(char) -> bool, 
• impl Clone for SipHasher24
• impl<I, P> Clone for TakeWhile<I, P> where
    I: Clone,
    P: Clone, 
• impl<'a, T, P> Clone for std::slice::Split<'a, T, P> where
    P: Clone + FnMut(&T) -> bool, 
• impl<'a, P> Clone for SplitTerminator<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl Clone for ParseIntError
• impl Clone for SipHasher
• impl<'a, T, P> Clone for std::slice::RSplit<'a, T, P> where
    P: Clone + FnMut(&T) -> bool,
    T: 'a + Clone, 
• impl<I> Clone for Take<I> where
    I: Clone, 
• impl Clone for std::sync::atomic::Ordering
• impl Clone for Utf8Error
• impl Clone for ParseFloatError
• impl<'a> Clone for CharSearcher<'a>
• impl<T> Clone for Rev<T> where
    T: Clone, 
• impl<T> Clone for Once<T> where
    T: Clone, 
• impl<I> Clone for DecodeUtf8<I> where
    I: Clone + Iterator<Item = u8>, 
• impl<Y, R> Clone for GeneratorState<Y, R> where
    R: Clone,
    Y: Clone, 
• impl<T> Clone for Wrapping<T> where
    T: Clone, 
• impl<'a> Clone for Bytes<'a>
• impl<I> Clone for Fuse<I> where
    I: Clone, 
• impl Clone for EscapeUnicode
• impl Clone for SipHasher13
• impl<'a, P> Clone for RMatches<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<T> Clone for RefCell<T> where
    T: Clone, 
• impl Clone for SearchStep
• impl<I> Clone for Skip<I> where
    I: Clone, 
• impl<T> Clone for ManuallyDrop<T> where
    T: Clone, 
• impl<'a, P> Clone for std::str::Split<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<I, P> Clone for SkipWhile<I, P> where
    I: Clone,
    P: Clone, 
• impl<'a, P> Clone for RSplitN<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl Clone for RangeFull
• impl<'a, A> Clone for std::option::Iter<'a, A>
• impl<'a> Clone for Arguments<'a>
• impl<'a, P> Clone for MatchIndices<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<A> Clone for std::option::IntoIter<A> where
    A: Clone, 
• impl<I, P> Clone for Filter<I, P> where
    I: Clone,
    P: Clone, 
• impl<Idx> Clone for RangeInclusive<Idx> where
    Idx: Clone, 
• impl<T> Clone for Empty<T>
• impl<H> Clone for BuildHasherDefault<H>
• impl<I> Clone for Cloned<I> where
    I: Clone, 
• impl<I, F> Clone for Map<I, F> where
    F: Clone,
    I: Clone, 
• impl<'a, P> Clone for SplitN<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<'a> Clone for LinesAny<'a>
• impl<Idx> Clone for RangeToInclusive<Idx> where
    Idx: Clone, 
• impl<Idx> Clone for RangeTo<Idx> where
    Idx: Clone, 
• impl<'a, P> Clone for std::str::RSplit<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<Idx> Clone for RangeFrom<Idx> where
    Idx: Clone, 
• impl<A> Clone for Repeat<A> where
    A: Clone, 
• impl<I, U, F> Clone for FlatMap<I, U, F> where
    F: Clone,
    I: Clone,
    U: Clone + IntoIterator,
    <U as IntoIterator>::IntoIter: Clone,
    <U as IntoIterator>::IntoIter: Clone, 
• impl Clone for EscapeDefault
• impl Clone for CharTryFromError
• impl<'a, P> Clone for RSplitTerminator<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl<'a> Clone for CharIndices<'a>
• impl<'a, P> Clone for Matches<'a, P> where
    P: Pattern<'a>,
    <P as Pattern<'a>>::Searcher: Clone, 
• impl Clone for ParseBoolError
• impl<'a, T> Clone for std::collections::btree_set::Iter<'a, T>
• impl<T> Clone for Arc<T> where
    T: ?Sized, 
• impl<K, V> Clone for BTreeMap<K, V> where
    K: Clone,
    V: Clone, 
• impl<'a, K, V> Clone for std::collections::btree_map::Range<'a, K, V>
• impl Clone for ParseError
• impl<T> Clone for Rc<T> where
    T: ?Sized, 
• impl<'a, T> Clone for std::collections::btree_set::Union<'a, T>
• impl Clone for CannotReallocInPlace
• impl<T> Clone for BinaryHeap<T> where
    T: Clone, 
• impl<T> Clone for BTreeSet<T> where
    T: Clone, 
• impl Clone for String
• impl<T> Clone for std::collections::linked_list::IntoIter<T> where
    T: Clone, 
• impl<'a, K, V> Clone for std::collections::btree_map::Values<'a, K, V>
• impl Clone for ExchangeHeapSingleton
• impl Clone for Heap
• impl<'a, T> Clone for std::collections::btree_set::SymmetricDifference<'a, T>
• impl<'a> Clone for EncodeUtf16<'a>
• impl<'a, B> Clone for Cow<'a, B> where
    B: ToOwned + ?Sized, 
• impl<'a, T> Clone for std::collections::btree_set::Range<'a, T>
• impl<'a, K, V> Clone for std::collections::btree_map::Keys<'a, K, V>
• impl<'a, T> Clone for std::collections::binary_heap::Iter<'a, T>
• impl<T> Clone for std::collections::binary_heap::IntoIter<T> where
    T: Clone, 
• impl<T> Clone for std::vec::IntoIter<T> where
    T: Clone, 
• impl<T> Clone for LinkedList<T> where
    T: Clone, 
• impl<T> Clone for std::collections::vec_deque::IntoIter<T> where
    T: Clone, 
• impl<T> Clone for VecDeque<T> where
    T: Clone, 
• impl<T> Clone for std::rc::Weak<T> where
    T: ?Sized, 
• impl<T> Clone for Bound<T> where
    T: Clone, 
• impl<'a, T> Clone for std::collections::linked_list::Iter<'a, T>
• impl<T> Clone for std::sync::Weak<T> where
    T: ?Sized, 
• impl<T> Clone for Box<[T]> where
    T: Clone, 
• impl<'a, K, V> Clone for std::collections::btree_map::Iter<'a, K, V>
• impl<'a, T> Clone for std::collections::btree_set::Difference<'a, T>
• impl Clone for Layout
• impl<T> Clone for Vec<T> where
    T: Clone, 
• impl<T> Clone for Box<T> where
    T: Clone, 
• impl<'a, T> Clone for std::collections::vec_deque::Iter<'a, T>
• impl Clone for Box<str>
• impl<'a, T> Clone for std::collections::btree_set::Intersection<'a, T>
• impl Clone for AllocErr
• impl Clone for LocalKeyState
• impl Clone for ThreadId
• impl Clone for Thread
• impl<K: Clone, V: Clone, S: Clone> Clone for HashMap<K, V, S>
• impl<'a, K, V> Clone for std::collections::hash_map::Iter<'a, K, V>
• impl<'a, K, V> Clone for std::collections::hash_map::Keys<'a, K, V>
• impl<'a, K, V> Clone for std::collections::hash_map::Values<'a, K, V>
• impl Clone for RandomState
• impl Clone for DefaultHasher
• impl<T: Clone, S: Clone> Clone for HashSet<T, S>
• impl<'a, K> Clone for std::collections::hash_set::Iter<'a, K>
• impl<'a, T, S> Clone for std::collections::hash_set::Intersection<'a, T, S>
• impl<'a, T, S> Clone for std::collections::hash_set::Difference<'a, T, S>
• impl<'a, T, S> Clone for std::collections::hash_set::SymmetricDifference<'a, T, S>
• impl<'a, T, S> Clone for std::collections::hash_set::Union<'a, T, S>
• impl Clone for VarError
• impl Clone for CString
• impl Clone for NulError
• impl Clone for FromBytesWithNulError
• impl Clone for IntoStringError
• impl Clone for OsString
• impl Clone for Metadata
• impl Clone for OpenOptions
• impl Clone for Permissions
• impl Clone for FileType
• impl<T: Clone> Clone for Cursor<T>
• impl Clone for ErrorKind
• impl Clone for SeekFrom
• impl Clone for IpAddr
• impl Clone for Ipv6MulticastScope
• impl Clone for Ipv4Addr
• impl Clone for Ipv6Addr
• impl Clone for std::net::SocketAddr
• impl Clone for SocketAddrV4
• impl Clone for SocketAddrV6
• impl Clone for AddrParseError
• impl Clone for Shutdown
• impl Clone for std::os::linux::raw::stat
• impl<'a> Clone for Prefix<'a>
• impl<'a> Clone for PrefixComponent<'a>
• impl<'a> Clone for Component<'a>
• impl<'a> Clone for Components<'a>
• impl<'a> Clone for std::path::Iter<'a>
• impl Clone for PathBuf
• impl Clone for StripPrefixError
• impl Clone for Output
• impl Clone for ExitStatus
• impl<T: Clone> Clone for SendError<T>
• impl Clone for RecvError
• impl Clone for TryRecvError
• impl Clone for RecvTimeoutError
• impl<T: Clone> Clone for TrySendError<T>
• impl<T> Clone for Sender<T>
• impl<T> Clone for SyncSender<T>
• impl Clone for WaitTimeoutResult
• impl Clone for Duration
• impl Clone for Instant
• impl Clone for SystemTime
• impl Clone for SystemTimeError
• impl<'a> Clone for EncodeWide<'a>
• impl Clone for std::os::unix::net::SocketAddr