# Struct miri::concurrency::sync::RwLock

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    struct RwLock {
        writer: Option<ThreadId>,
        readers: FxHashMap<ThreadId, usize>,
        writer_queue: VecDeque<ThreadId>,
        reader_queue: VecDeque<ThreadId>,
        clock_unlocked: VClock,
        clock_current_readers: VClock,
    }

Expand description

The read-write lock state.

## Fields§

§`writer: Option<ThreadId>`

The writer thread that currently owns the lock.

§`readers: FxHashMap<ThreadId, usize>`

The readers that currently own the lock and how many times they acquired the lock.

§`writer_queue: VecDeque<ThreadId>`

The queue of writer threads waiting for this lock.

§`reader_queue: VecDeque<ThreadId>`

The queue of reader threads waiting for this lock.

§`clock_unlocked: VClock`

Data race clock for writers. Tracks the happens-before ordering between each write access to a rwlock and is updated after a sequence of concurrent readers to track the happens- before ordering between the set of previous readers and the current writer. Contains the clock of the last thread to release a writer lock or the joined clock of the set of last threads to release shared reader locks.

§`clock_current_readers: VClock`

Data race clock for readers. This is temporary storage for the combined happens-before ordering for between all concurrent readers and the next writer, and the value is stored to the main data_race variable once all readers are finished. Has to be stored separately since reader lock acquires must load the clock of the last write and must not add happens-before orderings between shared reader locks. This is only relevant when there is an active reader.

## Trait Implementations§

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### impl Debug for RwLock

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#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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### impl Default for RwLock

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#### fn default() -> RwLock

Returns the “default value” for a type. Read more

## Auto Trait Implementations§

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### impl Freeze for RwLock

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### impl RefUnwindSafe for RwLock

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### impl Send for RwLock

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### impl Sync for RwLock

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### impl Unpin for RwLock

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### impl UnwindSafe for RwLock

## Blanket Implementations§

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### impl<T> Any for T
where T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for T
where T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for T
where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> Same for T

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#### type Output = T

Should always be `Self`
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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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### impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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#### fn vzip(self) -> V

## Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain `repr(...)` attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 232 bytes