Trait Send

1.0.0 · source

pub unsafe auto trait Send { }

Expand description

Types that can be transferred across thread boundaries.

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

An example of a non-Send type is the reference-counting pointer rc::Rc. If two threads attempt to clone Rcs that point to the same reference-counted value, they might try to update the reference count at the same time, which is undefined behavior because Rc doesn’t use atomic operations. Its cousin sync::Arc does use atomic operations (incurring some overhead) and thus is Send.

See the Nomicon and the Sync trait for more details.

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1.0.0 · source§

impl !Send for Arguments<'_>

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impl !Send for LocalWaker

1.26.0 · source§

impl !Send for Args

1.26.0 · source§

impl !Send for ArgsOs

1.6.0 · source§

impl Send for alloc::string::Drain<'_>

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impl Send for Bytes<'_>

1.36.0 · source§

impl Send for Atom

Immutable, so it’s safe to be shared between threads

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impl Send for Bump

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impl Send for PrefixRange

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impl Send for SharedDeserializeMapError

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impl Send for SharedSerializeMap

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impl Send for SharedSerializeMapError

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impl Send for SharedValidator

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impl Send for SuffixRange

1.44.0 · source§

impl<'a> Send for IoSlice<'a>

1.44.0 · source§

impl<'a> Send for IoSliceMut<'a>

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impl<'a> Send for ArchiveValidator<'a>

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impl<'a, 'b, K, Q, V, S, A> Send for OccupiedEntryRef<'a, 'b, K, Q, V, S, A>
where K: Send, Q: Sync + ?Sized, V: Send, S: Send, A: Send + Allocator,

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impl<'a, 'b, K, Q, V, S, A> Send for OccupiedEntryRef<'a, 'b, K, Q, V, S, A>
where K: Send, Q: Sync + ?Sized, V: Send, S: Send, A: Send + Allocator + Clone,

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impl<'a, 'bump> Send for Drain<'a, 'bump>

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impl<'a, 'bump, T> Send for Drain<'a, 'bump, T>
where T: Send,

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

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

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

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impl<'a, T> Send for ArcBorrow<'a, T>
where T: Sync + Send + ?Sized,

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

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impl<'a, T, O> Send for Iter<'a, T, O>
where T: BitStore, O: BitOrder, &'a mut BitSlice<T, O>: Send,

Original and Original

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impl<'a, T, O> Send for IterMut<'a, T, O>
where T: BitStore, O: BitOrder, &'a mut BitSlice<T, O>: Send,

Original and Original

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impl<'bump, T> Send for IntoIter<'bump, T>
where T: Send,

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impl<A> Send for SmallVec<A>
where A: Array, <A as Array>::Item: Send,

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impl<A, B> Send for ArcUnion<A, B>
where A: Sync + Send, B: Send + Sync,

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impl<Dyn> Send for core::ptr::metadata::DynMetadata<Dyn>
where Dyn: ?Sized,

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impl<Dyn> Send for DynMetadata<Dyn>
where Dyn: ?Sized,

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impl<H, T> Send for ThinArc<H, T>
where H: Sync + Send, T: Sync + Send,

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impl<K, V> Send for IterMut<'_, K, V>
where K: Send, V: Send,

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impl<K, V> Send for IterMut<'_, K, V>
where K: Send, V: Send,

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impl<K, V, S, A> Send for OccupiedEntry<'_, K, V, S, A>
where K: Send, V: Send, S: Send, A: Send + Allocator,

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impl<K, V, S, A> Send for OccupiedEntry<'_, K, V, S, A>
where K: Send, V: Send, S: Send, A: Send + Allocator + Clone,

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impl<K, V, S, A> Send for RawOccupiedEntryMut<'_, K, V, S, A>
where K: Send, V: Send, S: Send, A: Send + Allocator,

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impl<K, V, S, A> Send for RawOccupiedEntryMut<'_, K, V, S, A>
where K: Send, V: Send, S: Send, A: Send + Allocator + Clone,

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impl<M, T, O> Send for BitRef<'_, M, T, O>
where M: Mutability, T: BitStore + Sync, O: BitOrder,

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

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

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

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

1.0.0 · source§

impl<T> !Send for *const T
where T: ?Sized,

1.0.0 · source§

impl<T> !Send for *mut T
where T: ?Sized,

1.25.0 · source§

impl<T> !Send for NonNull<T>
where T: ?Sized,

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

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impl<T> !Send for std::sync::mutex::MappedMutexGuard<'_, T>
where T: ?Sized,

1.0.0 · source§

impl<T> !Send for MutexGuard<'_, T>
where T: ?Sized,

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impl<T> !Send for ReentrantLockGuard<'_, T>
where T: ?Sized,

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impl<T> !Send for std::sync::rwlock::MappedRwLockReadGuard<'_, T>
where T: ?Sized,

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impl<T> !Send for std::sync::rwlock::MappedRwLockWriteGuard<'_, T>
where T: ?Sized,

1.0.0 · source§

impl<T> !Send for RwLockReadGuard<'_, T>
where T: ?Sized,

1.0.0 · source§

impl<T> !Send for RwLockWriteGuard<'_, T>
where T: ?Sized,

1.0.0 · source§

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

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impl<T> Send for ThinBox<T>
where T: Send + ?Sized,

ThinBox<T> is Send if T is Send because the data is owned.

1.0.0 · source§

impl<T> Send for alloc::collections::linked_list::Iter<'_, T>
where T: Sync,

1.0.0 · source§

impl<T> Send for alloc::collections::linked_list::IterMut<'_, T>
where T: Send,

1.0.0 · source§

impl<T> Send for Cell<T>
where T: Send + ?Sized,

1.0.0 · source§

impl<T> Send for RefCell<T>
where T: Send + ?Sized,

1.28.0 · source§

impl<T> Send for NonZero<T>
where T: ZeroablePrimitive + Send,

1.31.0 · source§

impl<T> Send for ChunksExactMut<'_, T>
where T: Send,

1.0.0 · source§

impl<T> Send for ChunksMut<'_, T>
where T: Send,

1.0.0 · source§

impl<T> Send for core::slice::iter::Iter<'_, T>
where T: Sync,

1.0.0 · source§

impl<T> Send for core::slice::iter::IterMut<'_, T>
where T: Send,

1.31.0 · source§

impl<T> Send for RChunksExactMut<'_, T>
where T: Send,

1.31.0 · source§

impl<T> Send for RChunksMut<'_, T>
where T: Send,

1.0.0 · source§

impl<T> Send for AtomicPtr<T>

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impl<T> Send for std::sync::mpmc::Receiver<T>
where T: Send,

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impl<T> Send for std::sync::mpmc::Sender<T>
where T: Send,

1.0.0 · source§

impl<T> Send for std::sync::mpsc::Receiver<T>
where T: Send,

1.0.0 · source§

impl<T> Send for std::sync::mpsc::Sender<T>
where T: Send,

1.0.0 · source§

impl<T> Send for SyncSender<T>
where T: Send,

1.0.0 · source§

impl<T> Send for std::sync::mutex::Mutex<T>
where T: Send + ?Sized,

1.70.0 · source§

impl<T> Send for OnceLock<T>
where T: Send,

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impl<T> Send for ReentrantLock<T>
where T: Send + ?Sized,

1.0.0 · source§

impl<T> Send for std::sync::rwlock::RwLock<T>
where T: Send + ?Sized,

1.29.0 · source§

impl<T> Send for JoinHandle<T>

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

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impl<T> Send for BitSpanError<T>
where T: BitStore,

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impl<T> Send for Bucket<T>

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impl<T> Send for Bucket<T>

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impl<T> Send for BufferScratch<T>
where T: Send,

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impl<T> Send for MisalignError<T>

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impl<T> Send for OffsetArc<T>
where T: Sync + Send,

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impl<T> Send for OutBuf<'_, T>
where T: Send,

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impl<T> Send for OutRef<'_, T>
where T: Send,

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impl<T> Send for ScratchVec<T>
where T: Send,

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impl<T> Send for UniqueArc<T>
where T: Send + ?Sized,

1.0.0 · source§

impl<T, A> !Send for Rc<T, A>
where A: Allocator, T: ?Sized,

1.4.0 · source§

impl<T, A> !Send for alloc::rc::Weak<T, A>
where A: Allocator, T: ?Sized,

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impl<T, A> Send for Cursor<'_, T, A>
where T: Sync, A: Allocator + Sync,

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impl<T, A> Send for CursorMut<'_, T, A>
where T: Send, A: Allocator + Send,

1.0.0 · source§

impl<T, A> Send for LinkedList<T, A>
where T: Send, A: Allocator + Send,

1.6.0 · source§

impl<T, A> Send for alloc::collections::vec_deque::drain::Drain<'_, T, A>
where T: Send, A: Allocator + Send,

1.4.0 · source§

impl<T, A> Send for alloc::sync::Weak<T, A>
where T: Sync + Send + ?Sized, A: Allocator + Send,

1.6.0 · source§

impl<T, A> Send for alloc::vec::drain::Drain<'_, T, A>
where T: Send, A: Send + Allocator,

1.0.0 · source§

impl<T, A> Send for alloc::vec::into_iter::IntoIter<T, A>
where T: Send, A: Allocator + Send,

1.0.0 · source§

impl<T, A> Send for swc_common::sync::Lrc<T, A>
where T: Sync + Send + ?Sized, A: Allocator + Send,

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impl<T, A> Send for OccupiedEntry<'_, T, A>
where T: Send, A: Send + Allocator,

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impl<T, A> Send for RawDrain<'_, T, A>
where A: Allocator + Send, T: Send,

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impl<T, A> Send for RawDrain<'_, T, A>
where A: Allocator + Copy + Send, T: Send,

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impl<T, A> Send for RawIntoIter<T, A>
where A: Allocator + Send, T: Send,

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impl<T, A> Send for RawIntoIter<T, A>
where A: Allocator + Clone + Send, T: Send,

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impl<T, A> Send for RawTable<T, A>
where A: Allocator + Send, T: Send,

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impl<T, A> Send for RawTable<T, A>
where A: Allocator + Clone + Send, T: Send,

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impl<T, O> Send for BitBox<T, O>
where T: BitStore, O: BitOrder,

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impl<T, O> Send for BitSlice<T, O>
where T: BitStore + Sync, O: BitOrder,

§Bit-Slice Thread Safety

This allows bit-slice references to be moved across thread boundaries only when the underlying T element can tolerate concurrency.

All BitSlice references, shared or exclusive, are only threadsafe if the T element type is Send, because any given bit-slice reference may only have partial control of a memory element that is also being shared by a bit-slice reference on another thread. As such, this is never implemented for Cell<U>, but always implemented for AtomicU and U for a given unsigned integer type U.

Atomic integers safely handle concurrent writes, cells do not allow concurrency at all, so the only missing piece is &mut BitSlice<_, U: Unsigned>. This is handled by the aliasing system that the mutable splitters employ: a mutable reference to an unsynchronized bit-slice can only cross threads when no other handle is able to exist to the elements it governs. Splitting a mutable bit-slice causes the split halves to change over to either atomics or cells, so concurrency is either safe or impossible.

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