1.0.0[−][src]Trait core::marker::Sync

#[lang = "sync"]
pub unsafe auto trait Sync { }
[−]

Types for which it is safe to share references between threads.

This trait is automatically implemented when the compiler determines it's appropriate.

The precise definition is: a type T is Sync if and only if &T is Send. In other words, if there is no possibility of undefined behavior (including data races) when passing &T references between threads.

As one would expect, primitive types like u8 and f64 are all Sync, and so are simple aggregate types containing them, like tuples, structs and enums. More examples of basic Sync types include "immutable" types like &T, and those with simple inherited mutability, such as Box<T>, Vec<T> and most other collection types. (Generic parameters need to be Sync for their container to be Sync.)

A somewhat surprising consequence of the definition is that &mut T is Sync (if T is Sync) even though it seems like that might provide unsynchronized mutation. The trick is that a mutable reference behind a shared reference (that is, & &mut T) becomes read-only, as if it were a & &T. Hence there is no risk of a data race.

Types that are not Sync are those that have "interior mutability" in a non-thread-safe form, such as cell::Cell and cell::RefCell. These types allow for mutation of their contents even through an immutable, shared reference. For example the set method on Cell<T> takes &self, so it requires only a shared reference &Cell<T>. The method performs no synchronization, thus Cell cannot be Sync.

Another example of a non-Sync type is the reference-counting pointer rc::Rc. Given any reference &Rc<T>, you can clone a new Rc<T>, modifying the reference counts in a non-atomic way.

For cases when one does need thread-safe interior mutability, Rust provides atomic data types, as well as explicit locking via sync::Mutex and sync::RwLock. These types ensure that any mutation cannot cause data races, hence the types are Sync. Likewise, sync::Arc provides a thread-safe analogue of Rc.

Any types with interior mutability must also use the cell::UnsafeCell wrapper around the value(s) which can be mutated through a shared reference. Failing to doing this is undefined behavior. For example, transmute-ing from &T to &mut T is invalid.

See the Nomicon for more details about Sync.

Implementors

impl Sync for AtomicBool[src]

impl Sync for AtomicI128[src]

impl Sync for AtomicI16[src]

impl Sync for AtomicI32[src]

impl Sync for AtomicI64[src]

impl Sync for AtomicI8[src]

impl Sync for AtomicIsize[src]

impl Sync for AtomicU128[src]

impl Sync for AtomicU16[src]

impl Sync for AtomicU32[src]

impl Sync for AtomicU64[src]

impl Sync for AtomicU8[src]

impl Sync for AtomicUsize[src]

impl Sync for Waker[src]

impl<'_, T: Sync> Sync for core::slice::Iter<'_, T>[src]

impl<'_, T: Sync> Sync for core::slice::IterMut<'_, T>[src]

impl<T> Sync for AtomicPtr<T>[src]

impl<T: ?Sized> !Sync for *const T[src]

impl<T: ?Sized> !Sync for *mut T[src]

impl<T: ?Sized> !Sync for Cell<T>[src]

impl<T: ?Sized> !Sync for RefCell<T>[src]

impl<T: ?Sized> !Sync for UnsafeCell<T>[src]

impl<T: ?Sized> !Sync for NonNull<T>[src]

NonNull pointers are not Sync because the data they reference may be aliased.

impl<T: Sync> Sync for LinkedList<T>

impl<'_, T: Sync> Sync for Iter<'_, T>

impl<'_, T: Sync> Sync for IterMut<'_, T>

impl<'_, T: Sync> Sync for Drain<'_, T>

impl<T: ?Sized + Sync + Send> Sync for Arc<T>

impl<T: ?Sized + Sync + Send> Sync for Weak<T>

impl<T: ?Sized> !Sync for Rc<T>

impl<T: ?Sized> !Sync for Weak<T>

impl<'_> Sync for Drain<'_>

impl<T: Sync> Sync for IntoIter<T>

impl<'_, T: Sync> Sync for Drain<'_, T>

impl !Sync for TokenStream

impl !Sync for LexError

impl !Sync for Span

impl !Sync for LineColumn

impl !Sync for TokenTree

impl !Sync for Group

impl !Sync for Punct

Auto implementors

impl !Sync for Excess

impl !Sync for TraitObject

impl !Sync for RawWaker

impl Sync for core::cmp::Ordering

impl Sync for Infallible

impl Sync for c_void

impl Sync for Alignment

impl Sync for FpCategory

impl Sync for IntErrorKind

impl Sync for SearchStep

impl Sync for core::sync::atomic::Ordering

impl Sync for AllocErr

impl Sync for CannotReallocInPlace

impl Sync for Layout

impl Sync for LayoutErr

impl Sync for TypeId

impl Sync for float64x1_t

impl Sync for float64x2_t

impl Sync for int8x16x2_t

impl Sync for int8x16x3_t

impl Sync for int8x16x4_t

impl Sync for poly64x1_t

impl Sync for poly64x2_t

impl Sync for poly8x16x2_t

impl Sync for poly8x16x3_t

impl Sync for poly8x16x4_t

impl Sync for uint8x16x2_t

impl Sync for uint8x16x3_t

impl Sync for uint8x16x4_t

impl Sync for APSR

impl Sync for SY

impl Sync for float32x2_t

impl Sync for float32x4_t

impl Sync for int16x4_t

impl Sync for int16x8_t

impl Sync for int32x2_t

impl Sync for int32x4_t

impl Sync for int64x1_t

impl Sync for int64x2_t

impl Sync for int8x16_t

impl Sync for int8x8_t

impl Sync for int8x8x2_t

impl Sync for int8x8x3_t

impl Sync for int8x8x4_t

impl Sync for poly16x4_t

impl Sync for poly16x8_t

impl Sync for poly8x16_t

impl Sync for poly8x8_t

impl Sync for poly8x8x2_t

impl Sync for poly8x8x3_t

impl Sync for poly8x8x4_t

impl Sync for uint16x4_t

impl Sync for uint16x8_t

impl Sync for uint32x2_t

impl Sync for uint32x4_t

impl Sync for uint64x1_t

impl Sync for uint64x2_t

impl Sync for uint8x16_t

impl Sync for uint8x8_t

impl Sync for uint8x8x2_t

impl Sync for uint8x8x3_t

impl Sync for uint8x8x4_t

impl Sync for v16i8

impl Sync for v16u8

impl Sync for v2f64

impl Sync for v2i64

impl Sync for v2u64

impl Sync for v4f32

impl Sync for v4i32

impl Sync for v4u32

impl Sync for v8i16

impl Sync for v8u16

impl Sync for vector_bool_long

impl Sync for vector_double

impl Sync for vector_signed_long

impl Sync for vector_unsigned_long

impl Sync for v128

impl Sync for CpuidResult

impl Sync for __m128

impl Sync for __m128d

impl Sync for __m128i

impl Sync for __m256

impl Sync for __m256d

impl Sync for __m256i

impl Sync for __m512

impl Sync for __m512d

impl Sync for __m512i

impl Sync for __m64

impl Sync for TryFromSliceError

impl Sync for core::ascii::EscapeDefault

impl Sync for BorrowError

impl Sync for BorrowMutError

impl Sync for CharTryFromError

impl Sync for DecodeUtf16Error

impl Sync for core::char::EscapeDebug

impl Sync for core::char::EscapeDefault

impl Sync for core::char::EscapeUnicode

impl Sync for ParseCharError

impl Sync for ToLowercase

impl Sync for ToUppercase

impl Sync for UnicodeVersion

impl Sync for Error

impl Sync for SipHasher

impl Sync for PhantomPinned

impl Sync for NonZeroI128

impl Sync for NonZeroI16

impl Sync for NonZeroI32

impl Sync for NonZeroI64

impl Sync for NonZeroI8

impl Sync for NonZeroIsize

impl Sync for NonZeroU128

impl Sync for NonZeroU16

impl Sync for NonZeroU32

impl Sync for NonZeroU64

impl Sync for NonZeroU8

impl Sync for NonZeroUsize

impl Sync for ParseFloatError

impl Sync for ParseIntError

impl Sync for TryFromIntError

impl Sync for RangeFull

impl Sync for NoneError

impl Sync for Utf8Lossy

impl Sync for ParseBoolError

impl Sync for Utf8Error

impl Sync for RawWakerVTable

impl Sync for Duration

impl<'a> !Sync for VaList<'a>

impl<'a> !Sync for Arguments<'a>

impl<'a> !Sync for Formatter<'a>

impl<'a> !Sync for PanicInfo<'a>

impl<'a> Sync for Location<'a>

impl<'a> Sync for Utf8LossyChunk<'a>

impl<'a> Sync for Utf8LossyChunksIter<'a>

impl<'a> Sync for CharSearcher<'a>

impl<'a> Sync for Bytes<'a>

impl<'a> Sync for CharIndices<'a>

impl<'a> Sync for Chars<'a>

impl<'a> Sync for EncodeUtf16<'a>

impl<'a> Sync for core::str::EscapeDebug<'a>

impl<'a> Sync for core::str::EscapeDefault<'a>

impl<'a> Sync for core::str::EscapeUnicode<'a>

impl<'a> Sync for Lines<'a>

impl<'a> Sync for LinesAny<'a>

impl<'a> Sync for SplitAsciiWhitespace<'a>

impl<'a> Sync for SplitWhitespace<'a>

impl<'a> Sync for Context<'a>

impl<'a, 'b> !Sync for DebugList<'a, 'b>

impl<'a, 'b> !Sync for DebugMap<'a, 'b>

impl<'a, 'b> !Sync for DebugSet<'a, 'b>

impl<'a, 'b> !Sync for DebugStruct<'a, 'b>

impl<'a, 'b> !Sync for DebugTuple<'a, 'b>

impl<'a, 'b> Sync for CharSliceSearcher<'a, 'b>

impl<'a, 'b> Sync for StrSearcher<'a, 'b>

impl<'a, A> Sync for core::option::Iter<'a, A> where
    A: Sync, 

impl<'a, A> Sync for core::option::IterMut<'a, A> where
    A: Sync, 

impl<'a, F> Sync for CharPredicateSearcher<'a, F> where
    F: MultiCharEq + Sync, 

impl<'a, P> Sync for MatchIndices<'a, P> where
    <P as Pattern<'a>>::Searcher: Sync, 

impl<'a, P> Sync for Matches<'a, P> where
    <P as Pattern<'a>>::Searcher: Sync, 

impl<'a, P> Sync for RMatchIndices<'a, P> where
    <P as Pattern<'a>>::Searcher: Sync, 

impl<'a, P> Sync for RMatches<'a, P> where
    <P as Pattern<'a>>::Searcher: Sync, 

impl<'a, P> Sync for core::str::RSplit<'a, P> where
    <P as Pattern<'a>>::Searcher: Sync, 

impl<'a, P> Sync for core::str::RSplitN<'a, P> where
    <P as Pattern<'a>>::Searcher: Sync, 

impl<'a, P> Sync for RSplitTerminator<'a, P> where
    <P as Pattern<'a>>::Searcher: Sync, 

impl<'a, P> Sync for core::str::Split<'a, P> where
    <P as Pattern<'a>>::Searcher: Sync, 

impl<'a, P> Sync for core::str::SplitN<'a, P> where
    <P as Pattern<'a>>::Searcher: Sync, 

impl<'a, P> Sync for SplitTerminator<'a, P> where
    <P as Pattern<'a>>::Searcher: Sync, 

impl<'a, T> Sync for core::result::Iter<'a, T> where
    T: Sync, 

impl<'a, T> Sync for core::result::IterMut<'a, T> where
    T: Sync, 

impl<'a, T> Sync for Chunks<'a, T> where
    T: Sync, 

impl<'a, T> Sync for ChunksExact<'a, T> where
    T: Sync, 

impl<'a, T> Sync for ChunksExactMut<'a, T> where
    T: Sync, 

impl<'a, T> Sync for ChunksMut<'a, T> where
    T: Sync, 

impl<'a, T> Sync for RChunks<'a, T> where
    T: Sync, 

impl<'a, T> Sync for RChunksExact<'a, T> where
    T: Sync, 

impl<'a, T> Sync for RChunksExactMut<'a, T> where
    T: Sync, 

impl<'a, T> Sync for RChunksMut<'a, T> where
    T: Sync, 

impl<'a, T> Sync for Windows<'a, T> where
    T: Sync, 

impl<'a, T, P> Sync for core::slice::RSplit<'a, T, P> where
    P: Sync,
    T: Sync, 

impl<'a, T, P> Sync for RSplitMut<'a, T, P> where
    P: Sync,
    T: Sync, 

impl<'a, T, P> Sync for core::slice::RSplitN<'a, T, P> where
    P: Sync,
    T: Sync, 

impl<'a, T, P> Sync for RSplitNMut<'a, T, P> where
    P: Sync,
    T: Sync, 

impl<'a, T, P> Sync for core::slice::Split<'a, T, P> where
    P: Sync,
    T: Sync, 

impl<'a, T, P> Sync for SplitMut<'a, T, P> where
    P: Sync,
    T: Sync, 

impl<'a, T, P> Sync for core::slice::SplitN<'a, T, P> where
    P: Sync,
    T: Sync, 

impl<'a, T, P> Sync for SplitNMut<'a, T, P> where
    P: Sync,
    T: Sync, 

impl<'b, T> !Sync for Ref<'b, T>

impl<'b, T> !Sync for RefMut<'b, T>

impl<A> Sync for Repeat<A> where
    A: Sync, 

impl<A> Sync for core::option::IntoIter<A> where
    A: Sync, 

impl<A, B> Sync for Chain<A, B> where
    A: Sync,
    B: Sync, 

impl<A, B> Sync for Zip<A, B> where
    A: Sync,
    B: Sync, 

impl<F> Sync for FromFn<F> where
    F: Sync, 

impl<F> Sync for OnceWith<F> where
    F: Sync, 

impl<F> Sync for RepeatWith<F> where
    F: Sync, 

impl<H> Sync for BuildHasherDefault<H> where
    H: Sync, 

impl<I> Sync for DecodeUtf16<I> where
    I: Sync, 

impl<I> Sync for Cloned<I> where
    I: Sync, 

impl<I> Sync for Copied<I> where
    I: Sync, 

impl<I> Sync for Cycle<I> where
    I: Sync, 

impl<I> Sync for Enumerate<I> where
    I: Sync, 

impl<I> Sync for Flatten<I> where
    I: Sync,
    <<I as Iterator>::Item as IntoIterator>::IntoIter: Sync, 

impl<I> Sync for Fuse<I> where
    I: Sync, 

impl<I> Sync for Peekable<I> where
    I: Sync,
    <I as Iterator>::Item: Sync, 

impl<I> Sync for Skip<I> where
    I: Sync, 

impl<I> Sync for StepBy<I> where
    I: Sync, 

impl<I> Sync for Take<I> where
    I: Sync, 

impl<I, F> Sync for FilterMap<I, F> where
    F: Sync,
    I: Sync, 

impl<I, F> Sync for Inspect<I, F> where
    F: Sync,
    I: Sync, 

impl<I, F> Sync for Map<I, F> where
    F: Sync,
    I: Sync, 

impl<I, P> Sync for Filter<I, P> where
    I: Sync,
    P: Sync, 

impl<I, P> Sync for SkipWhile<I, P> where
    I: Sync,
    P: Sync, 

impl<I, P> Sync for TakeWhile<I, P> where
    I: Sync,
    P: Sync, 

impl<I, St, F> Sync for Scan<I, St, F> where
    F: Sync,
    I: Sync,
    St: Sync, 

impl<I, U, F> Sync for FlatMap<I, U, F> where
    F: Sync,
    I: Sync,
    <U as IntoIterator>::IntoIter: Sync, 

impl<Idx> Sync for Range<Idx> where
    Idx: Sync, 

impl<Idx> Sync for RangeFrom<Idx> where
    Idx: Sync, 

impl<Idx> Sync for RangeInclusive<Idx> where
    Idx: Sync, 

impl<Idx> Sync for RangeTo<Idx> where
    Idx: Sync, 

impl<Idx> Sync for RangeToInclusive<Idx> where
    Idx: Sync, 

impl<P> Sync for Pin<P> where
    P: Sync, 

impl<T> Sync for Bound<T> where
    T: Sync, 

impl<T> Sync for Option<T> where
    T: Sync, 

impl<T> Sync for Poll<T> where
    T: Sync, 

impl<T> Sync for Reverse<T> where
    T: Sync, 

impl<T> Sync for Empty<T> where
    T: Sync, 

impl<T> Sync for Once<T> where
    T: Sync, 

impl<T> Sync for Rev<T> where
    T: Sync, 

impl<T> Sync for Discriminant<T>

impl<T> Sync for Wrapping<T> where
    T: Sync, 

impl<T> Sync for core::result::IntoIter<T> where
    T: Sync, 

impl<T> Sync for MaybeUninit<T> where
    T: Sync, 

impl<T, E> Sync for Result<T, E> where
    E: Sync,
    T: Sync, 

impl<T, F> Sync for Successors<T, F> where
    F: Sync,
    T: Sync, 

impl<T: ?Sized> Sync for PhantomData<T> where
    T: Sync, 

impl<T: ?Sized> Sync for ManuallyDrop<T> where
    T: Sync, 

impl<Y, R> Sync for GeneratorState<Y, R> where
    R: Sync,
    Y: Sync, 

impl Sync for Global

impl<T: ?Sized> Sync for Box<T> where
    T: Sync, 

impl Sync for CollectionAllocErr

impl<T> Sync for BinaryHeap<T> where
    T: Sync, 

impl<'a, T> Sync for PeekMut<'a, T> where
    T: Sync, 

impl<'a, T> Sync for Iter<'a, T> where
    T: Sync, 

impl<T> Sync for IntoIter<T> where
    T: Sync, 

impl<'a, T> Sync for Drain<'a, T> where
    T: Sync, 

impl<K, V> Sync for BTreeMap<K, V> where
    K: Sync,
    V: Sync, 

impl<'a, K, V> Sync for Iter<'a, K, V> where
    K: Sync,
    V: Sync, 

impl<'a, K, V> Sync for IterMut<'a, K, V> where
    K: Sync,
    V: Sync, 

impl<K, V> Sync for IntoIter<K, V> where
    K: Sync,
    V: Sync, 

impl<'a, K, V> Sync for Keys<'a, K, V> where
    K: Sync,
    V: Sync, 

impl<'a, K, V> Sync for Values<'a, K, V> where
    K: Sync,
    V: Sync, 

impl<'a, K, V> Sync for ValuesMut<'a, K, V> where
    K: Sync,
    V: Sync, 

impl<'a, K, V> Sync for Range<'a, K, V> where
    K: Sync,
    V: Sync, 

impl<'a, K, V> Sync for RangeMut<'a, K, V> where
    K: Sync,
    V: Sync, 

impl<'a, K, V> Sync for VacantEntry<'a, K, V> where
    K: Sync,
    V: Sync, 

impl<'a, K, V> Sync for OccupiedEntry<'a, K, V> where
    K: Sync,
    V: Sync, 

impl<'a, K, V> Sync for Entry<'a, K, V> where
    K: Sync,
    V: Sync, 

impl<T> Sync for BTreeSet<T> where
    T: Sync, 

impl<'a, T> Sync for Iter<'a, T> where
    T: Sync, 

impl<T> Sync for IntoIter<T> where
    T: Sync, 

impl<'a, T> Sync for Range<'a, T> where
    T: Sync, 

impl<'a, T> Sync for Difference<'a, T> where
    T: Sync, 

impl<'a, T> Sync for SymmetricDifference<'a, T> where
    T: Sync, 

impl<'a, T> Sync for Intersection<'a, T> where
    T: Sync, 

impl<'a, T> Sync for Union<'a, T> where
    T: Sync, 

impl<T> Sync for IntoIter<T> where
    T: Sync, 

impl<'a, T, F> !Sync for DrainFilter<'a, T, F>

impl<T> Sync for VecDeque<T> where
    T: Sync, 

impl<'a, T> Sync for Iter<'a, T> where
    T: Sync, 

impl<'a, T> Sync for IterMut<'a, T> where
    T: Sync, 

impl<T> Sync for IntoIter<T> where
    T: Sync, 

impl<'a, B: ?Sized> Sync for Cow<'a, B> where
    B: Sync,
    <B as ToOwned>::Owned: Sync, 

impl Sync for String

impl Sync for FromUtf8Error

impl Sync for FromUtf16Error

impl<T> Sync for Vec<T> where
    T: Sync, 

impl<'a, I> Sync for Splice<'a, I> where
    I: Sync,
    <I as Iterator>::Item: Sync, 

impl<'a, T, F> Sync for DrainFilter<'a, T, F> where
    F: Sync,
    T: Sync, 

impl !Sync for Diagnostic

impl !Sync for SourceFile

impl !Sync for Ident

impl !Sync for Literal

impl Sync for Level

impl Sync for Delimiter

impl Sync for Spacing

impl !Sync for IntoIter

impl Sync for Bencher

impl Sync for TestDesc

impl !Sync for TestDescAndFn

impl Sync for Metric

impl Sync for Options

impl Sync for TestOpts

impl Sync for BenchSamples

impl Sync for MetricMap

impl Sync for Concurrent

impl Sync for TestName

impl Sync for NamePadding

impl !Sync for TestFn

impl Sync for BenchMode

impl Sync for ShouldPanic

impl Sync for ColorConfig

impl Sync for OutputFormat

impl Sync for RunIgnored

impl Sync for TestResult

impl Sync for TestEvent

impl Sync for Summary