Trait frame_support::dispatch::marker::Sync1.0.0[][src]

#[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

impl Sync for FormatSpec

impl Sync for Alignment

impl Sync for Count

impl !Sync for Args[src]

impl !Sync for ArgsOs[src]

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

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

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

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

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

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

impl Sync for Once[src]

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

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

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

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

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

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

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

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

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

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

impl Sync for AtomicU16[src]

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

impl Sync for AtomicBool[src]

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

impl Sync for AtomicI32[src]

impl<Dyn> Sync for DynMetadata<Dyn> where
    Dyn: ?Sized
[src]

impl Sync for AtomicU8[src]

impl Sync for AtomicU32[src]

impl Sync for AtomicU64[src]

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

impl Sync for AtomicI64[src]

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

impl Sync for Waker[src]

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

impl Sync for AtomicI16[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 Sync for AtomicIsize[src]

impl Sync for AtomicUsize[src]

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

impl Sync for AtomicI8[src]

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

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

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

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

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

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

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

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

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

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

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

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

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

impl<T, C> Sync for OwnedRef<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 OwnedRefMut<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, T> Sync for Drain<'a, T> where
    T: Sync + Array
[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>, 
[src]

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

impl Sync for GuardNoSend[src]

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

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

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

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

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
[src]

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

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
[src]

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

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

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

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

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

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

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

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

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

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

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

impl Sync for AtomicWaker[src]

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

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

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

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

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

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

impl Sync for isize

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

impl Sync for [u8]

impl Sync for char

impl Sync for u128

impl Sync for u16

impl Sync for i128

impl Sync for i16

impl Sync for str

impl Sync for f64

impl Sync for u64

impl Sync for u8

impl Sync for i64

impl Sync for i8

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

impl Sync for bool

impl Sync for f32

impl Sync for u32

impl Sync for usize

impl Sync for i32

Loading content...

Implementors

Loading content...

Auto implementors

impl Sync for frame_support::dispatch::fmt::Alignment

impl Sync for Never

impl Sync for Void

impl Sync for RuntimeMetadata

impl Sync for StorageEntryModifier

impl Sync for StorageEntryType

impl Sync for StorageHasher

impl Sync for DispatchError

impl Sync for InvalidTransaction

impl Sync for TransactionSource

impl Sync for TransactionValidityError

impl Sync for UnknownTransaction

impl Sync for ChildInfo

impl Sync for ChildType

impl Sync for KillOutcome

impl Sync for BalanceStatus

impl Sync for ExistenceRequirement

impl Sync for DispatchClass

impl Sync for Pays

impl Sync for FrameTransactionPriority

impl Sync for RuntimeLogger

impl Sync for Writer

impl Sync for Error

impl Sync for PhantomPinned

impl Sync for ErrorMetadata

impl Sync for FunctionArgumentMetadata

impl Sync for FunctionMetadata

impl Sync for ModuleConstantMetadata

impl Sync for EventMetadata

impl Sync for OuterEventMetadata

impl Sync for Instance0

impl Sync for Instance1

impl Sync for Instance2

impl Sync for Instance3

impl Sync for Instance4

impl Sync for Instance5

impl Sync for Instance6

impl Sync for Instance7

impl Sync for Instance8

impl Sync for Instance9

impl Sync for Instance10

impl Sync for Instance11

impl Sync for Instance12

impl Sync for Instance13

impl Sync for Instance14

impl Sync for Instance15

impl Sync for DefaultByteGetter

impl Sync for ExtrinsicMetadata

impl Sync for ModuleMetadata

impl Sync for RuntimeMetadataPrefixed

impl Sync for StorageEntryMetadata

impl Sync for StorageMetadata

impl Sync for Blake2_128

impl Sync for Blake2_128Concat

impl Sync for Blake2_256

impl Sync for Identity

impl Sync for InherentData

impl Sync for Twox64Concat

impl Sync for Twox128

impl Sync for Twox256

impl Sync for ValidTransaction

impl Sync for OptionQuery

impl Sync for ValueQuery

impl Sync for CallMetadata

impl Sync for GetDefault

impl Sync for PalletVersion

impl Sync for SaturatingCurrencyToVote

impl Sync for TestRandomness

impl Sync for U128CurrencyToVote

impl Sync for WithdrawReasons

impl Sync for BlockExecutionWeight

impl Sync for ExtrinsicBaseWeight

impl Sync for ParityDbWeight

impl Sync for RocksDbWeight

impl Sync for DispatchInfo

impl Sync for PostDispatchInfo

impl Sync for RuntimeDbWeight

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

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

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

impl<B, O> Sync for DecodeDifferent<B, O> where
    B: Sync,
    O: Sync

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

impl<Balance> Sync for WeightToFeeCoefficient<Balance> where
    Balance: Sync

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

impl<BlockNumber> Sync for DispatchTime<BlockNumber> where
    BlockNumber: Sync

impl<E> Sync for FnEncode<E>

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

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

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

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

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

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

impl<R> Sync for TransactionOutcome<R> where
    R: Sync

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

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

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

impl<T> Sync for PrefixIterator<T>

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

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

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

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

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

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

Loading content...