1.0.0[][src]Trait frame_support::dispatch::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.

Implementations on Foreign Types

impl Sync for Argument[src]

impl Sync for FormatSpec[src]

impl Sync for Alignment[src]

impl Sync for Count[src]

impl<'_, T> Sync for RwLockWriteGuard<'_, T> where
    T: Sync + ?Sized
[src]

impl Sync for Once[src]

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

impl<T> Sync for RwLock<T> where
    T: Send + Sync + ?Sized
[src]

impl<T> Sync for SyncOnceCell<T> where
    T: Send + Sync
[src]

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

impl<'_, T> Sync for MutexGuard<'_, T> where
    T: Sync + ?Sized
[src]

impl !Sync for Args[src]

impl<T, F> Sync for SyncLazy<T, F> where
    F: Send,
    SyncOnceCell<T>: Sync
[src]

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

impl<T> Sync for Mutex<T> where
    T: Send + ?Sized
[src]

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

impl !Sync for ArgsOs[src]

impl<'_, T> Sync for RwLockReadGuard<'_, T> where
    T: Sync + ?Sized
[src]

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

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

impl Sync for Waker[src]

impl Sync for AtomicI16[src]

impl Sync for AtomicI32[src]

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

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

impl Sync for AtomicBool[src]

impl Sync for AtomicU8[src]

impl Sync for AtomicU32[src]

impl Sync for AtomicI64[src]

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

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

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

impl Sync for AtomicUsize[src]

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

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

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

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

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

impl Sync for AtomicU64[src]

impl Sync for AtomicIsize[src]

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

impl Sync for AtomicU16[src]

impl Sync for AtomicI8[src]

impl<'_, T> Sync for CursorMut<'_, T> where
    T: Sync
[src]

impl<T> Sync for Weak<T> where
    T: Send + Sync + ?Sized
[src]

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

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

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

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

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

impl<'_, T, A> Sync for Drain<'_, T, A> where
    T: Sync,
    A: Sync + Allocator
[src]

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

impl<'_> Sync for Drain<'_>[src]

impl<T, A> Sync for IntoIter<T, A> where
    T: Sync,
    A: Allocator
[src]

impl<T> Sync for Arc<T> where
    T: Send + Sync + ?Sized
[src]

impl<'_, T> Sync for Cursor<'_, T> where
    T: Sync
[src]

impl<'_, T> Sync for Drain<'_, T> where
    T: Sync
[src]

impl<'a, A> Sync for Drain<'a, A> where
    A: Array + Sync
[src]

impl<T> Sync for ThreadLocal<T> where
    T: Send

impl<T, F> Sync for Lazy<T, F> where
    F: Send,
    OnceCell<T>: Sync

impl<'a, R, T> Sync for MappedRwLockReadGuard<'a, R, T> where
    T: 'a + Sync + ?Sized,
    R: 'a + RawRwLock, 

impl<'a, R, T> Sync for MutexGuard<'a, R, T> where
    T: 'a + Sync + ?Sized,
    R: 'a + RawMutex + Sync

impl<'a, R, T> Sync for MappedMutexGuard<'a, R, T> where
    T: 'a + Sync + ?Sized,
    R: 'a + RawMutex + Sync

impl<'a, R, G, T> Sync for ReentrantMutexGuard<'a, R, G, T> where
    T: 'a + Sync + ?Sized,
    R: 'a + RawMutex + Sync,
    G: 'a + GetThreadId + Sync

impl<'a, R, T> Sync for MappedRwLockWriteGuard<'a, R, T> where
    T: 'a + Sync + ?Sized,
    R: 'a + RawRwLock, 

impl<R, T> Sync for Mutex<R, T> where
    T: Send + ?Sized,
    R: RawMutex + Sync

impl<R, G> Sync for RawReentrantMutex<R, G> where
    R: RawMutex + Sync,
    G: GetThreadId + Sync

impl<R, T> Sync for RwLock<R, T> where
    T: Send + Sync + ?Sized,
    R: RawRwLock + Sync

impl Sync for GuardNoSend

impl<'a, R, G, T> Sync for MappedReentrantMutexGuard<'a, R, G, T> where
    T: 'a + Sync + ?Sized,
    R: 'a + RawMutex + Sync,
    G: 'a + GetThreadId + Sync

impl<R, G, T> Sync for ReentrantMutex<R, G, T> where
    T: Send + ?Sized,
    R: RawMutex + Sync,
    G: GetThreadId + Sync

impl<'a, R, T> Sync for RwLockUpgradableReadGuard<'a, R, T> where
    T: 'a + Sync + ?Sized,
    R: 'a + RawRwLockUpgrade, 

impl<T, F, S> Sync for ScopeGuard<T, F, S> where
    T: Sync,
    F: FnOnce(T),
    S: Strategy
[src]

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

impl<T, C> Sync for OwnedRefMut<T, C> where
    C: Config,
    T: Sync + Clear + Default
[src]

impl<T, C> Sync for Pool<T, C> where
    C: Config,
    T: Sync + Clear + Default
[src]

impl<T, C> Sync for Slab<T, C> where
    C: Config,
    T: Sync
[src]

impl<T, C> Sync for OwnedRef<T, C> where
    C: Config,
    T: Sync + Clear + Default
[src]

impl<T, C> Sync for OwnedEntry<T, C> where
    C: Config,
    T: Sync
[src]

impl<'a, A> Sync for Drain<'a, A> where
    A: Array + Sync
[src]

impl<T, N> Sync for GenericArray<T, N> where
    T: Sync,
    N: ArrayLength<T>, 

impl<T, N> Sync for GenericArray<T, N> where
    T: Sync,
    N: ArrayLength<T>, 

impl<T> Sync for RawIntoIter<T> where
    T: Sync

impl<'_, T> Sync for RawDrain<'_, T> where
    T: Sync

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

impl<T> Sync for RawTable<T> where
    T: Sync

impl<'_, K, V, S> Sync for RawOccupiedEntryMut<'_, K, V, S> where
    K: Sync,
    V: Sync,
    S: Sync

impl Sync for AtomicWaker

impl<'_, T> Sync for MutexLockFuture<'_, T> where
    T: ?Sized

impl<'_, T, U> Sync for MappedMutexGuard<'_, T, U> where
    T: Sync + ?Sized,
    U: Sync + ?Sized

impl<T> Sync for Mutex<T> where
    T: Send + ?Sized

impl<'_, T> Sync for MutexGuard<'_, T> where
    T: Sync + ?Sized

impl<Fut> Sync for FuturesUnordered<Fut> where
    Fut: Sync

impl Sync for NotifyHandle[src]

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

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

impl Sync for AtomicTask[src]

impl<'_, K, V> Sync for OccupiedEntry<'_, K, V> where
    K: Sync,
    V: Sync
[src]

impl Sync for isize[src]

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

impl Sync for [u8][src]

impl Sync for char[src]

impl Sync for u128[src]

impl Sync for u16[src]

impl Sync for i128[src]

impl Sync for i16[src]

impl Sync for str[src]

impl Sync for f64[src]

impl Sync for u64[src]

impl Sync for u8[src]

impl Sync for i64[src]

impl Sync for i8[src]

impl<T, const N: usize> Sync for [T; N] where
    T: Sync
[src]

impl Sync for bool[src]

impl Sync for f32[src]

impl Sync for u32[src]

impl Sync for usize[src]

impl Sync for i32[src]

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Implementors

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Auto implementors

impl Sync for frame_support::dispatch::fmt::Alignment[src]

impl Sync for Never[src]

impl Sync for Void[src]

impl Sync for RuntimeMetadata[src]

impl Sync for StorageEntryModifier[src]

impl Sync for StorageEntryType[src]

impl Sync for StorageHasher[src]

impl Sync for DispatchError[src]

impl Sync for InvalidTransaction[src]

impl Sync for TransactionSource[src]

impl Sync for TransactionValidityError[src]

impl Sync for UnknownTransaction[src]

impl Sync for ChildInfo[src]

impl Sync for ChildType[src]

impl Sync for KillOutcome[src]

impl Sync for BalanceStatus[src]

impl Sync for ExistenceRequirement[src]

impl Sync for DispatchClass[src]

impl Sync for Pays[src]

impl Sync for FrameTransactionPriority[src]

impl Sync for RuntimeLogger[src]

impl Sync for Writer[src]

impl Sync for Error[src]

impl Sync for PhantomPinned[src]

impl Sync for ErrorMetadata[src]

impl Sync for FunctionArgumentMetadata[src]

impl Sync for FunctionMetadata[src]

impl Sync for ModuleConstantMetadata[src]

impl Sync for EventMetadata[src]

impl Sync for OuterEventMetadata[src]

impl Sync for Instance0[src]

impl Sync for Instance1[src]

impl Sync for Instance2[src]

impl Sync for Instance3[src]

impl Sync for Instance4[src]

impl Sync for Instance5[src]

impl Sync for Instance6[src]

impl Sync for Instance7[src]

impl Sync for Instance8[src]

impl Sync for Instance9[src]

impl Sync for Instance10[src]

impl Sync for Instance11[src]

impl Sync for Instance12[src]

impl Sync for Instance13[src]

impl Sync for Instance14[src]

impl Sync for Instance15[src]

impl Sync for DefaultByteGetter[src]

impl Sync for ExtrinsicMetadata[src]

impl Sync for ModuleMetadata[src]

impl Sync for RuntimeMetadataPrefixed[src]

impl Sync for StorageEntryMetadata[src]

impl Sync for StorageMetadata[src]

impl Sync for Blake2_128[src]

impl Sync for Blake2_128Concat[src]

impl Sync for Blake2_256[src]

impl Sync for Identity[src]

impl Sync for InherentData[src]

impl Sync for Twox64Concat[src]

impl Sync for Twox128[src]

impl Sync for Twox256[src]

impl Sync for ValidTransaction[src]

impl Sync for OptionQuery[src]

impl Sync for ValueQuery[src]

impl Sync for CallMetadata[src]

impl Sync for GetDefault[src]

impl Sync for PalletVersion[src]

impl Sync for SaturatingCurrencyToVote[src]

impl Sync for TestRandomness[src]

impl Sync for U128CurrencyToVote[src]

impl Sync for WithdrawReasons[src]

impl Sync for BlockExecutionWeight[src]

impl Sync for ExtrinsicBaseWeight[src]

impl Sync for ParityDbWeight[src]

impl Sync for RocksDbWeight[src]

impl Sync for DispatchInfo[src]

impl Sync for PostDispatchInfo[src]

impl Sync for RuntimeDbWeight[src]

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

impl<'a> !Sync for Formatter<'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, T> Sync for frame_support::dispatch::result::Iter<'a, T> where
    T: Sync
[src]

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

impl<B, O> Sync for DecodeDifferent<B, O> where
    B: Sync,
    O: Sync
[src]

impl<B, P> Sync for SignedImbalance<B, P> where
    P: Sync,
    <P as Imbalance<B>>::Opposite: Sync
[src]

impl<Balance> Sync for WeightToFeeCoefficient<Balance> where
    Balance: Sync
[src]

impl<Balance, Imbalance, Part1, Target1, Part2, Target2> Sync for SplitTwoWays<Balance, Imbalance, Part1, Target1, Part2, Target2> where
    Balance: Sync,
    Imbalance: Sync,
    Part1: Sync,
    Part2: Sync,
    Target1: Sync,
    Target2: Sync
[src]

impl<BlockNumber> Sync for DispatchTime<BlockNumber> where
    BlockNumber: Sync
[src]

impl<E> Sync for FnEncode<E>[src]

impl<F, T> Sync for ClearFilterGuard<F, T> where
    T: Sync,
    <F as FilterStack<T>>::Stack: Sync
[src]

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

impl<K, T, H> Sync for StorageKeyIterator<K, T, H> where
    H: Sync,
    K: Sync,
    T: Sync
[src]

impl<Prefix, Hasher1, Key1, Hasher2, Key2, Value, QueryKind, OnEmpty> Sync for StorageDoubleMap<Prefix, Hasher1, Key1, Hasher2, Key2, Value, QueryKind, OnEmpty> where
    Hasher1: Sync,
    Hasher2: Sync,
    Key1: Sync,
    Key2: Sync,
    OnEmpty: Sync,
    Prefix: Sync,
    QueryKind: Sync,
    Value: Sync
[src]

impl<Prefix, Hasher, Key, Value, QueryKind, OnEmpty> Sync for StorageMap<Prefix, Hasher, Key, Value, QueryKind, OnEmpty> where
    Hasher: Sync,
    Key: Sync,
    OnEmpty: Sync,
    Prefix: Sync,
    QueryKind: Sync,
    Value: Sync
[src]

impl<Prefix, Value, QueryKind, OnEmpty> Sync for StorageValue<Prefix, Value, QueryKind, OnEmpty> where
    OnEmpty: Sync,
    Prefix: Sync,
    QueryKind: Sync,
    Value: Sync
[src]

impl<R> Sync for TransactionOutcome<R> where
    R: Sync
[src]

impl<S, L, K, T> Sync for StorageMapShim<S, L, K, T> where
    K: Sync,
    L: Sync,
    S: Sync,
    T: Sync
[src]

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

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

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

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

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

impl<T, A> Sync for Vec<T, A> where
    A: Sync,
    T: Sync
[src]

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

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

impl<WD, CD, PF> Sync for FunctionOf<WD, CD, PF> where
    CD: Sync,
    PF: Sync,
    WD: Sync
[src]

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