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 and 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. 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 AtomicI8[src]

impl Sync for AtomicI16[src]

impl Sync for AtomicI32[src]

impl Sync for AtomicI64[src]

impl Sync for AtomicIsize[src]

impl Sync for AtomicU8[src]

impl Sync for AtomicU16[src]

impl Sync for AtomicU32[src]

impl Sync for AtomicU64[src]

impl Sync for AtomicUsize[src]

impl Sync for Waker[src]

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

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

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

impl<T: Sync> Sync for core::slice::IterMut<'_, 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.

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Auto implementors

impl !Sync for TraitObject[src]

impl !Sync for RawWaker[src]

impl Sync for core::cmp::Ordering[src]

impl Sync for Infallible[src]

impl Sync for c_void[src]

impl Sync for Alignment[src]

impl Sync for FpCategory[src]

impl Sync for IntErrorKind[src]

impl Sync for SearchStep[src]

impl Sync for core::sync::atomic::Ordering[src]

impl Sync for AllocError[src]

impl Sync for Layout[src]

impl Sync for LayoutError[src]

impl Sync for TypeId[src]

impl Sync for float64x1_t[src]

impl Sync for float64x2_t[src]

impl Sync for int8x16x2_t[src]

impl Sync for int8x16x3_t[src]

impl Sync for int8x16x4_t[src]

impl Sync for poly8x16x2_t[src]

impl Sync for poly8x16x3_t[src]

impl Sync for poly8x16x4_t[src]

impl Sync for uint8x16x2_t[src]

impl Sync for uint8x16x3_t[src]

impl Sync for uint8x16x4_t[src]

impl Sync for APSR[src]

impl Sync for SY[src]

impl Sync for float32x2_t[src]

impl Sync for float32x4_t[src]

impl Sync for int8x8_t[src]

impl Sync for int8x8x2_t[src]

impl Sync for int8x8x3_t[src]

impl Sync for int8x8x4_t[src]

impl Sync for int8x16_t[src]

impl Sync for int16x4_t[src]

impl Sync for int16x8_t[src]

impl Sync for int32x2_t[src]

impl Sync for int32x4_t[src]

impl Sync for int64x1_t[src]

impl Sync for int64x2_t[src]

impl Sync for poly8x8_t[src]

impl Sync for poly8x8x2_t[src]

impl Sync for poly8x8x3_t[src]

impl Sync for poly8x8x4_t[src]

impl Sync for poly8x16_t[src]

impl Sync for poly16x4_t[src]

impl Sync for poly16x8_t[src]

impl Sync for poly64x1_t[src]

impl Sync for poly64x2_t[src]

impl Sync for uint8x8_t[src]

impl Sync for uint8x8x2_t[src]

impl Sync for uint8x8x3_t[src]

impl Sync for uint8x8x4_t[src]

impl Sync for uint8x16_t[src]

impl Sync for uint16x4_t[src]

impl Sync for uint16x8_t[src]

impl Sync for uint32x2_t[src]

impl Sync for uint32x4_t[src]

impl Sync for uint64x1_t[src]

impl Sync for uint64x2_t[src]

impl Sync for vector_bool_long[src]

impl Sync for vector_double[src]

impl Sync for vector_signed_long[src]

impl Sync for vector_unsigned_long[src]

impl Sync for v128[src]

impl Sync for CpuidResult[src]

impl Sync for __m128[src]

impl Sync for __m128d[src]

impl Sync for __m128i[src]

impl Sync for __m256[src]

impl Sync for __m256d[src]

impl Sync for __m256i[src]

impl Sync for __m512[src]

impl Sync for __m512d[src]

impl Sync for __m512i[src]

impl Sync for TryFromSliceError[src]

impl Sync for core::ascii::EscapeDefault[src]

impl Sync for BorrowError[src]

impl Sync for BorrowMutError[src]

impl Sync for CharTryFromError[src]

impl Sync for DecodeUtf16Error[src]

impl Sync for core::char::EscapeDebug[src]

impl Sync for core::char::EscapeDefault[src]

impl Sync for core::char::EscapeUnicode[src]

impl Sync for ParseCharError[src]

impl Sync for ToLowercase[src]

impl Sync for ToUppercase[src]

impl Sync for Error[src]

impl Sync for SipHasher[src]

impl Sync for PhantomPinned[src]

impl Sync for NonZeroI8[src]

impl Sync for NonZeroI16[src]

impl Sync for NonZeroI32[src]

impl Sync for NonZeroI64[src]

impl Sync for NonZeroI128[src]

impl Sync for NonZeroIsize[src]

impl Sync for NonZeroU8[src]

impl Sync for NonZeroU16[src]

impl Sync for NonZeroU32[src]

impl Sync for NonZeroU64[src]

impl Sync for NonZeroU128[src]

impl Sync for NonZeroUsize[src]

impl Sync for ParseFloatError[src]

impl Sync for ParseIntError[src]

impl Sync for TryFromIntError[src]

impl Sync for RangeFull[src]

impl Sync for NoneError[src]

impl Sync for Utf8Lossy[src]

impl Sync for ParseBoolError[src]

impl Sync for Utf8Error[src]

impl Sync for RawWakerVTable[src]

impl Sync for Duration[src]

impl<'a> !Sync for Arguments<'a>[src]

impl<'a> !Sync for Formatter<'a>[src]

impl<'a> !Sync for PanicInfo<'a>[src]

impl<'a> Sync for Location<'a>[src]

impl<'a> Sync for Utf8LossyChunk<'a>[src]

impl<'a> Sync for Utf8LossyChunksIter<'a>[src]

impl<'a> Sync for CharSearcher<'a>[src]

impl<'a> Sync for Bytes<'a>[src]

impl<'a> Sync for CharIndices<'a>[src]

impl<'a> Sync for Chars<'a>[src]

impl<'a> Sync for EncodeUtf16<'a>[src]

impl<'a> Sync for core::str::EscapeDebug<'a>[src]

impl<'a> Sync for core::str::EscapeDefault<'a>[src]

impl<'a> Sync for core::str::EscapeUnicode<'a>[src]

impl<'a> Sync for Lines<'a>[src]

impl<'a> Sync for LinesAny<'a>[src]

impl<'a> Sync for SplitAsciiWhitespace<'a>[src]

impl<'a> Sync for SplitWhitespace<'a>[src]

impl<'a> Sync for Context<'a>[src]

impl<'a, 'b> !Sync for DebugList<'a, 'b>[src]

impl<'a, 'b> !Sync for DebugMap<'a, 'b>[src]

impl<'a, 'b> !Sync for DebugSet<'a, 'b>[src]

impl<'a, 'b> !Sync for DebugStruct<'a, 'b>[src]

impl<'a, 'b> !Sync for DebugTuple<'a, 'b>[src]

impl<'a, 'b> Sync for CharSliceSearcher<'a, 'b>[src]

impl<'a, 'b> Sync for StrSearcher<'a, 'b>[src]

impl<'a, 'f> !Sync for VaList<'a, 'f>[src]

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

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

impl<'a, F> Sync for CharPredicateSearcher<'a, F> where
    F: Sync
[src]

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

impl<'a, T, P> Sync for GroupBy<'a, T, P> where
    P: Sync,
    T: Sync
[src]

impl<'a, T, P> Sync for GroupByMut<'a, T, P> where
    P: Sync,
    T: Sync
[src]

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

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

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

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

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

impl<'a, T, P> Sync for SplitInclusive<'a, T, P> where
    P: Sync,
    T: Sync
[src]

impl<'a, T, P> Sync for SplitInclusiveMut<'a, T, P> where
    P: Sync,
    T: Sync
[src]

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

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

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

impl<'a, T, const N: usize> !Sync for ArrayWindows<'a, T, N>[src]

impl<'a, T, const N: usize> Sync for ArrayChunks<'a, T, N> where
    T: Sync
[src]

impl<'a, T, const N: usize> Sync for ArrayChunksMut<'a, T, N> where
    T: Sync
[src]

impl<'b, T> !Sync for Ref<'b, T>[src]

impl<'b, T> !Sync for RefMut<'b, T>[src]

impl<'f> !Sync for VaListImpl<'f>[src]

impl<A> Sync for Repeat<A> where
    A: Sync
[src]

impl<A> Sync for core::option::IntoIter<A> where
    A: Sync
[src]

impl<A, B> Sync for Chain<A, B> where
    A: Sync,
    B: Sync
[src]

impl<A, B> Sync for Zip<A, B> where
    A: Sync,
    B: Sync
[src]

impl<B, C> Sync for ControlFlow<B, C> where
    B: Sync,
    C: Sync
[src]

impl<F> Sync for PollFn<F> where
    F: Sync
[src]

impl<F> Sync for FromFn<F> where
    F: Sync
[src]

impl<F> Sync for OnceWith<F> where
    F: Sync
[src]

impl<F> Sync for RepeatWith<F> where
    F: Sync
[src]

impl<H> Sync for BuildHasherDefault<H> where
    H: Sync
[src]

impl<I> Sync for DecodeUtf16<I> where
    I: Sync
[src]

impl<I> Sync for Cloned<I> where
    I: Sync
[src]

impl<I> Sync for Copied<I> where
    I: Sync
[src]

impl<I> Sync for Cycle<I> where
    I: Sync
[src]

impl<I> Sync for Enumerate<I> where
    I: Sync
[src]

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

impl<I> Sync for Fuse<I> where
    I: Sync
[src]

impl<I> Sync for Intersperse<I> where
    I: Sync,
    <I as Iterator>::Item: Sync
[src]

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

impl<I> Sync for Skip<I> where
    I: Sync
[src]

impl<I> Sync for StepBy<I> where
    I: Sync
[src]

impl<I> Sync for Take<I> where
    I: Sync
[src]

impl<I, F> Sync for FilterMap<I, F> where
    F: Sync,
    I: Sync
[src]

impl<I, F> Sync for Inspect<I, F> where
    F: Sync,
    I: Sync
[src]

impl<I, F> Sync for Map<I, F> where
    F: Sync,
    I: Sync
[src]

impl<I, G> Sync for IntersperseWith<I, G> where
    G: Sync,
    I: Sync,
    <I as Iterator>::Item: Sync
[src]

impl<I, P> Sync for Filter<I, P> where
    I: Sync,
    P: Sync
[src]

impl<I, P> Sync for MapWhile<I, P> where
    I: Sync,
    P: Sync
[src]

impl<I, P> Sync for SkipWhile<I, P> where
    I: Sync,
    P: Sync
[src]

impl<I, P> Sync for TakeWhile<I, P> where
    I: Sync,
    P: Sync
[src]

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

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

impl<Idx> Sync for Range<Idx> where
    Idx: Sync
[src]

impl<Idx> Sync for RangeFrom<Idx> where
    Idx: Sync
[src]

impl<Idx> Sync for RangeInclusive<Idx> where
    Idx: Sync
[src]

impl<Idx> Sync for RangeTo<Idx> where
    Idx: Sync
[src]

impl<Idx> Sync for RangeToInclusive<Idx> where
    Idx: Sync
[src]

impl<P> Sync for Pin<P> where
    P: Sync
[src]

impl<T> !Sync for OnceCell<T>[src]

impl<T> Sync for Bound<T> where
    T: Sync
[src]

impl<T> Sync for Option<T> where
    T: Sync
[src]

impl<T> Sync for Poll<T> where
    T: Sync
[src]

impl<T> Sync for Reverse<T> where
    T: Sync
[src]

impl<T> Sync for Pending<T> where
    T: Sync
[src]

impl<T> Sync for Ready<T> where
    T: Sync
[src]

impl<T> Sync for Once<T> where
    T: Sync
[src]

impl<T> Sync for Rev<T> where
    T: Sync
[src]

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

impl<T> Sync for Wrapping<T> where
    T: Sync
[src]

impl<T> Sync for core::result::IntoIter<T> where
    T: Sync
[src]

impl<T> Sync for MaybeUninit<T> where
    T: Sync
[src]

impl<T, E> Sync for Result<T, E> where
    E: Sync,
    T: Sync
[src]

impl<T, F> Sync for Successors<T, F> where
    F: Sync,
    T: Sync
[src]

impl<T, F = fn() -> T> !Sync for Lazy<T, F>[src]

impl<T, const N: usize> Sync for core::array::IntoIter<T, N> where
    T: Sync
[src]

impl<T: ?Sized> Sync for PhantomData<T> where
    T: Sync
[src]

impl<T: ?Sized> Sync for ManuallyDrop<T> where
    T: Sync
[src]

impl<Y, R> Sync for GeneratorState<Y, R> where
    R: Sync,
    Y: Sync
[src]

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