1.0.0[][src]Trait scale_info::prelude::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 Weak<T> where
    T: Send + Sync + ?Sized
[src]

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

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

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

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

impl<'_> Sync for scale_info::prelude::string::Drain<'_>1.6.0[src]

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

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

impl<'_, T> Sync for scale_info::prelude::collections::linked_list::Iter<'_, T> where
    T: Sync
[src]

impl<'_, T> Sync for scale_info::prelude::collections::linked_list::IterMut<'_, T> where
    T: Sync
[src]

impl<'_, T> Sync for scale_info::prelude::collections::vec_deque::Drain<'_, T> where
    T: Sync
1.6.0[src]

impl<'_, T> Sync for scale_info::prelude::collections::vec_deque::IterMut<'_, T> where
    T: Sync
[src]

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

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

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

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Auto implementors

impl Sync for Fieldless[src]

impl Sync for Fields[src]

impl Sync for NamedFields[src]

impl Sync for NoFields[src]

impl Sync for NoVariants[src]

impl Sync for UnnamedFields[src]

impl Sync for VariantFields[src]

impl Sync for Variants[src]

impl Sync for PathAssigned[src]

impl Sync for PathNotAssigned[src]

impl Sync for PathError[src]

impl Sync for TypeDefPrimitive[src]

impl Sync for MetaForm[src]

impl Sync for Ordering[src]

impl Sync for TryReserveError[src]

impl Sync for scale_info::prelude::fmt::Alignment[src]

impl Sync for FpCategory[src]

impl Sync for IntErrorKind[src]

impl Sync for TypeId[src]

impl Sync for DefaultHasher[src]

impl Sync for RandomState[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 FromUtf8Error[src]

impl Sync for FromUtf16Error[src]

impl Sync for String[src]

impl Sync for MetaType[src]

impl Sync for Registry[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, I, A> Sync for Splice<'a, I, A> where
    A: Sync,
    I: Sync,
    <I as Iterator>::Item: Sync
[src]

impl<'a, K> Sync for scale_info::prelude::collections::hash_set::Drain<'a, K> where
    K: Sync
[src]

impl<'a, K> Sync for scale_info::prelude::collections::hash_set::Iter<'a, K> where
    K: Sync
[src]

impl<'a, K, F> Sync for scale_info::prelude::collections::hash_set::DrainFilter<'a, K, F> where
    F: Sync,
    K: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::btree_map::Entry<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::hash_map::Entry<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::btree_map::Iter<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::btree_map::IterMut<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::btree_map::Keys<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::btree_map::OccupiedEntry<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::btree_map::Range<'a, K, V> where
    K: Sync,
    V: Sync
[src]

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

impl<'a, K, V> Sync for scale_info::prelude::collections::btree_map::VacantEntry<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::btree_map::Values<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::btree_map::ValuesMut<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::hash_map::Drain<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::hash_map::Iter<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::hash_map::IterMut<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::hash_map::Keys<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::hash_map::OccupiedEntry<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::hash_map::VacantEntry<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::hash_map::Values<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V> Sync for scale_info::prelude::collections::hash_map::ValuesMut<'a, K, V> where
    K: Sync,
    V: Sync
[src]

impl<'a, K, V, F> Sync for scale_info::prelude::collections::btree_map::DrainFilter<'a, K, V, F> where
    F: Sync,
    K: Sync,
    V: Sync
[src]

impl<'a, K, V, F> Sync for scale_info::prelude::collections::hash_map::DrainFilter<'a, K, V, F> where
    F: Sync,
    K: Sync,
    V: Sync
[src]

impl<'a, K, V, S> Sync for RawEntryMut<'a, K, V, S> where
    K: Sync,
    S: Sync,
    V: Sync
[src]

impl<'a, K, V, S> Sync for RawEntryBuilder<'a, K, V, S> where
    K: Sync,
    S: Sync,
    V: Sync
[src]

impl<'a, K, V, S> Sync for RawEntryBuilderMut<'a, K, V, S> where
    K: Sync,
    S: Sync,
    V: Sync
[src]

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

impl<'a, K, V, S> Sync for RawVacantEntryMut<'a, K, V, S> where
    K: Sync,
    S: Sync,
    V: Sync
[src]

impl<'a, T> Sync for Symbol<'a, T>[src]

impl<'a, T> Sync for scale_info::prelude::collections::binary_heap::Drain<'a, T> where
    T: Sync
[src]

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

impl<'a, T> Sync for scale_info::prelude::collections::binary_heap::Iter<'a, T> where
    T: Sync
[src]

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

impl<'a, T> Sync for scale_info::prelude::collections::btree_set::Difference<'a, T> where
    T: Sync
[src]

impl<'a, T> Sync for scale_info::prelude::collections::btree_set::Intersection<'a, T> where
    T: Sync
[src]

impl<'a, T> Sync for scale_info::prelude::collections::btree_set::Iter<'a, T> where
    T: Sync
[src]

impl<'a, T> Sync for scale_info::prelude::collections::btree_set::Range<'a, T> where
    T: Sync
[src]

impl<'a, T> Sync for scale_info::prelude::collections::btree_set::SymmetricDifference<'a, T> where
    T: Sync
[src]

impl<'a, T> Sync for scale_info::prelude::collections::btree_set::Union<'a, T> where
    T: Sync
[src]

impl<'a, T> Sync for scale_info::prelude::collections::vec_deque::Iter<'a, T> where
    T: Sync
[src]

impl<'a, T, F> !Sync for scale_info::prelude::collections::linked_list::DrainFilter<'a, T, F>[src]

impl<'a, T, F> Sync for scale_info::prelude::collections::btree_set::DrainFilter<'a, T, F> where
    F: Sync,
    T: Sync
[src]

impl<'a, T, F, A> Sync for scale_info::prelude::vec::DrainFilter<'a, T, F, A> where
    A: Sync,
    F: Sync,
    T: Sync
[src]

impl<'a, T, S> Sync for scale_info::prelude::collections::hash_set::Difference<'a, T, S> where
    S: Sync,
    T: Sync
[src]

impl<'a, T, S> Sync for scale_info::prelude::collections::hash_set::Intersection<'a, T, S> where
    S: Sync,
    T: Sync
[src]

impl<'a, T, S> Sync for scale_info::prelude::collections::hash_set::SymmetricDifference<'a, T, S> where
    S: Sync,
    T: Sync
[src]

impl<'a, T, S> Sync for scale_info::prelude::collections::hash_set::Union<'a, T, S> where
    S: Sync,
    T: Sync
[src]

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

impl<K> Sync for scale_info::prelude::collections::hash_set::IntoIter<K> where
    K: Sync
[src]

impl<K, V> Sync for scale_info::prelude::collections::btree_map::IntoIter<K, V> where
    K: Sync,
    V: Sync
[src]

impl<K, V> Sync for scale_info::prelude::collections::btree_map::IntoKeys<K, V> where
    K: Sync,
    V: Sync
[src]

impl<K, V> Sync for scale_info::prelude::collections::btree_map::IntoValues<K, V> where
    K: Sync,
    V: Sync
[src]

impl<K, V> Sync for scale_info::prelude::collections::hash_map::IntoIter<K, V> where
    K: Sync,
    V: Sync
[src]

impl<K, V> Sync for scale_info::prelude::collections::hash_map::IntoKeys<K, V> where
    K: Sync,
    V: Sync
[src]

impl<K, V> Sync for scale_info::prelude::collections::hash_map::IntoValues<K, V> where
    K: Sync,
    V: Sync
[src]

impl<K, V> Sync for BTreeMap<K, V> where
    K: Sync,
    V: Sync
[src]

impl<K, V, S> Sync for HashMap<K, V, S> where
    K: Sync,
    S: Sync,
    V: Sync
[src]

impl<S> Sync for TypeBuilder<S>[src]

impl<S> Sync for PortableForm<S> where
    S: Sync
[src]

impl<S> Sync for PortableRegistry<S> where
    S: Sync
[src]

impl<T> Sync for TypeDef<T> where
    <T as Form>::String: Sync,
    <T as Form>::Type: Sync
[src]

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

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

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

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

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

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

impl<T> Sync for scale_info::prelude::collections::binary_heap::IntoIter<T> where
    T: Sync
[src]

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

impl<T> Sync for scale_info::prelude::collections::btree_set::IntoIter<T> where
    T: Sync
[src]

impl<T> Sync for scale_info::prelude::collections::linked_list::IntoIter<T> where
    T: Sync
[src]

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

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

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

impl<T> Sync for scale_info::prelude::collections::vec_deque::IntoIter<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 Field<T> where
    <T as Form>::String: Sync,
    <T as Form>::Type: Sync
[src]

impl<T> Sync for Path<T> where
    <T as Form>::String: Sync
[src]

impl<T> Sync for Type<T> where
    <T as Form>::String: Sync,
    <T as Form>::Type: Sync
[src]

impl<T> Sync for TypeDefArray<T> where
    <T as Form>::Type: Sync
[src]

impl<T> Sync for TypeDefComposite<T> where
    <T as Form>::String: Sync,
    <T as Form>::Type: Sync
[src]

impl<T> Sync for TypeDefPhantom<T> where
    <T as Form>::Type: Sync
[src]

impl<T> Sync for TypeDefSequence<T> where
    <T as Form>::Type: Sync
[src]

impl<T> Sync for TypeDefTuple<T> where
    <T as Form>::Type: Sync
[src]

impl<T> Sync for TypeDefVariant<T> where
    <T as Form>::String: Sync,
    <T as Form>::Type: Sync
[src]

impl<T> Sync for Variant<T> where
    <T as Form>::String: Sync,
    <T as Form>::Type: Sync
[src]

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

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

impl<T, S> Sync for HashSet<T, S> where
    S: Sync,
    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<T: ?Sized, A> Sync for Box<T, A> where
    A: Sync,
    T: Sync
[src]

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