#[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.
This trait can be used with #[derive]
if all fields are Clone
. The derive
d implementation of clone
calls clone
on each field.
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 } }
fn clone(&self) -> Self
Returns a copy of the value.
let hello = "Hello"; // &str implements Clone assert_eq!("Hello", hello.clone());
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.
impl Clone for TryFromSliceError
[src]
fn clone(&self) -> TryFromSliceError
[src]
fn clone_from(&mut self, source: &Self)
impl<T> Clone for NonZero<T> where
T: Zeroable + Clone,
[src]
impl<I> Clone for Utf16Encoder<I> where
I: Clone,
[src]
fn clone(&self) -> Utf16Encoder<I>
[src]
fn clone_from(&mut self, source: &Self)
impl<'a> Clone for EncodeUtf16<'a>
impl<T> Clone for Rc<T> where
T: ?Sized,
impl<T> Clone for std::vec::IntoIter<T> where
T: Clone,
impl Clone for String
impl<T> Clone for std::rc::Weak<T> where
T: ?Sized,
impl<T> Clone for BinaryHeap<T> where
T: Clone,
impl<'a, T> Clone for std::collections::btree_set::SymmetricDifference<'a, T>
impl<T> Clone for std::collections::vec_deque::IntoIter<T> where
T: Clone,
impl<'a, T> Clone for std::collections::btree_set::Range<'a, T>
impl<'a, T> Clone for std::collections::btree_set::Union<'a, T>
impl<T> Clone for Box<T> where
T: Clone,
impl<T> Clone for std::collections::binary_heap::IntoIter<T> where
T: Clone,
impl<T> Clone for BTreeSet<T> where
T: Clone,
impl<'a, T> Clone for std::collections::binary_heap::Iter<'a, T>
impl Clone for ExchangeHeapSingleton
impl<T> Clone for Bound<T> where
T: Clone,
impl<T> Clone for Arc<T> where
T: ?Sized,
impl<T> Clone for VecDeque<T> where
T: Clone,
impl<'a, B> Clone for Cow<'a, B> where
B: ToOwned + ?Sized,
impl<K, V> Clone for BTreeMap<K, V> where
K: Clone,
V: Clone,
impl<'a, T> Clone for std::collections::btree_set::Iter<'a, T>
impl Clone for Layout
impl<T> Clone for LinkedList<T> where
T: Clone,
impl<T> Clone for Vec<T> where
T: Clone,
impl Clone for Box<str>
impl<'a, T> Clone for std::collections::vec_deque::Iter<'a, T>
impl Clone for AllocErr
impl<T> Clone for Box<[T]> where
T: Clone,
impl<'a, K, V> Clone for std::collections::btree_map::Values<'a, K, V>
impl Clone for ParseError
impl Clone for Heap
impl<'a, K, V> Clone for std::collections::btree_map::Keys<'a, K, V>
impl<T> Clone for std::sync::Weak<T> where
T: ?Sized,
impl Clone for CannotReallocInPlace
impl<'a, K, V> Clone for std::collections::btree_map::Range<'a, K, V>
impl<'a, T> Clone for std::collections::btree_set::Difference<'a, T>
impl<T> Clone for std::collections::linked_list::IntoIter<T> where
T: Clone,
impl<'a, T> Clone for std::collections::btree_set::Intersection<'a, T>
impl<'a, K, V> Clone for std::collections::btree_map::Iter<'a, K, V>
impl<'a, T> Clone for std::collections::linked_list::Iter<'a, T>
impl Clone for TypeId
impl Clone for std::sync::atomic::Ordering
impl<T> Clone for Discriminant<T>
impl<Idx> Clone for RangeFrom<Idx> where
Idx: Clone,
impl<A> Clone for std::option::IntoIter<A> where
A: Clone,
impl<'a, P> Clone for SplitN<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<I> Clone for Fuse<I> where
I: Clone,
impl Clone for FpCategory
impl<I, P> Clone for SkipWhile<I, P> where
I: Clone,
P: Clone,
impl<T> Clone for ManuallyDrop<T> where
T: Clone,
impl<I> Clone for Peekable<I> where
I: Clone + Iterator,
<I as Iterator>::Item: Clone,
impl<'a, P> Clone for RMatchIndices<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<I, F> Clone for Map<I, F> where
F: Clone,
I: Clone,
impl<'a, P> Clone for SplitTerminator<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<Y, R> Clone for GeneratorState<Y, R> where
R: Clone,
Y: Clone,
impl<'a, A> Clone for std::option::Iter<'a, A>
impl Clone for Error
impl Clone for EscapeUnicode
impl Clone for ParseIntError
impl<T> Clone for Once<T> where
T: Clone,
impl Clone for EscapeDefault
impl Clone for ParseFloatError
impl<'a> Clone for Chars<'a>
impl<T> Clone for std::result::IntoIter<T> where
T: Clone,
impl Clone for ParseBoolError
impl Clone for TryFromIntError
impl<'a, P> Clone for RMatches<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<I> Clone for Cloned<I> where
I: Clone,
impl<'a> Clone for Bytes<'a>
impl<I, F> Clone for FilterMap<I, F> where
F: Clone,
I: Clone,
impl Clone for ParseCharError
impl<I> Clone for Cycle<I> where
I: Clone,
impl<'a> Clone for CharIndices<'a>
impl<I, F> Clone for Inspect<I, F> where
F: Clone,
I: Clone,
impl<I> Clone for DecodeUtf8<I> where
I: Clone + Iterator<Item = u8>,
impl Clone for TraitObject
impl<I, P> Clone for Filter<I, P> where
I: Clone,
P: Clone,
impl Clone for SearchStep
impl Clone for Utf8Error
impl<'a, P> Clone for Matches<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl Clone for Infallible
impl<'a, 'b> Clone for StrSearcher<'a, 'b>
impl<A, B> Clone for Zip<A, B> where
A: Clone,
B: Clone,
impl<T> Clone for Option<T> where
T: Clone,
impl<I> Clone for StepBy<I> where
I: Clone,
impl Clone for SipHasher13
impl<'a, P> Clone for RSplitTerminator<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl Clone for SipHasher
impl<T> Clone for Cell<T> where
T: Copy,
impl<T> Clone for Wrapping<T> where
T: Clone,
impl Clone for SipHasher24
impl<'a, T, P> Clone for std::slice::Split<'a, T, P> where
P: Clone + FnMut(&T) -> bool,
impl<'a, T, P> Clone for std::slice::RSplit<'a, T, P> where
P: Clone + FnMut(&T) -> bool,
T: 'a + Clone,
impl Clone for EscapeDebug
impl<'a, F> Clone for CharPredicateSearcher<'a, F> where
F: Clone + FnMut(char) -> bool,
impl<I> Clone for Skip<I> where
I: Clone,
impl Clone for NoneError
impl<T, E> Clone for Result<T, E> where
E: Clone,
T: Clone,
impl<'a, T> Clone for Chunks<'a, T>
impl<T> Clone for Empty<T>
impl<Idx> Clone for std::ops::Range<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<'a, T> Clone for std::slice::Iter<'a, T>
impl<T> Clone for PhantomData<T> where
T: ?Sized,
impl<Idx> Clone for RangeInclusive<Idx> where
Idx: Clone,
impl<I> Clone for Take<I> where
I: Clone,
impl<Idx> Clone for RangeToInclusive<Idx> where
Idx: Clone,
impl<'a> Clone for LinesAny<'a>
impl Clone for std::cmp::Ordering
impl<I> Clone for Enumerate<I> where
I: Clone,
impl<'a, 'b> Clone for CharSliceSearcher<'a, 'b>
impl<'a, P> Clone for std::str::Split<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<'a, T> Clone for std::result::Iter<'a, T>
impl<I, St, F> Clone for Scan<I, St, F> where
F: Clone,
I: Clone,
St: Clone,
impl<'a> Clone for Arguments<'a>
impl<I, P> Clone for TakeWhile<I, P> where
I: Clone,
P: Clone,
impl<T> Clone for Rev<T> where
T: Clone,
impl<T> Clone for RefCell<T> where
T: Clone,
impl Clone for CharTryFromError
impl<'a, T> Clone for Windows<'a, T>
impl<A, B> Clone for Chain<A, B> where
A: Clone,
B: Clone,
impl<H> Clone for BuildHasherDefault<H>
impl<'a> Clone for Lines<'a>
impl<'a> Clone for CharSearcher<'a>
impl<A> Clone for Repeat<A> where
A: Clone,
impl Clone for RangeFull
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<T> Clone for Unique<T> where
T: ?Sized,
impl<'a, P> Clone for RSplitN<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<Idx> Clone for RangeTo<Idx> where
Idx: Clone,
impl<'a, P> Clone for MatchIndices<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: Clone,
impl<T> Clone for Shared<T> where
T: ?Sized,
impl Clone for DecodeUtf16Error
impl<'a> Clone for SplitWhitespace<'a>
impl Clone for UnicodeVersion
impl<I> Clone for DecodeUtf16<I> where
I: Clone + Iterator<Item = u16>,
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 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
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/clone/trait.Clone.html