[][src]Struct tokio::sync::Semaphore

pub struct Semaphore { /* fields omitted */ }

Counting semaphore performing asynchronous permit aquisition.

A semaphore maintains a set of permits. Permits are used to synchronize access to a shared resource. A semaphore differs from a mutex in that it can allow more than one concurrent caller to access the shared resource at a time.

When acquire is called and the semaphore has remaining permits, the function immediately returns a permit. However, if no remaining permits are available, acquire (asynchronously) waits until an outstanding permit is dropped. At this point, the freed permit is assigned to the caller.

Implementations

impl Semaphore[src]

pub fn new(permits: usize) -> Self[src]

Creates a new semaphore with the initial number of permits.

pub fn available_permits(&self) -> usize[src]

Returns the current number of available permits.

pub fn add_permits(&self, n: usize)[src]

Adds n new permits to the semaphore.

The maximum number of permits is usize::MAX >> 3, and this function will panic if the limit is exceeded.

pub async fn acquire<'_, '_>(&'_ self) -> SemaphorePermit<'_>[src]

Acquires permit from the semaphore.

pub fn try_acquire(&self) -> Result<SemaphorePermit, TryAcquireError>[src]

Tries to acquire a permit from the semaphore.

pub async fn acquire_owned(self: Arc<Self>) -> OwnedSemaphorePermit[src]

Acquires permit from the semaphore.

The semaphore must be wrapped in an Arc to call this method.

pub fn try_acquire_owned(
    self: Arc<Self>
) -> Result<OwnedSemaphorePermit, TryAcquireError>
[src]

Tries to acquire a permit from the semaphore.

The semaphore must be wrapped in an Arc to call this method.

Trait Implementations

impl Debug for Semaphore[src]

Auto Trait Implementations

impl !RefUnwindSafe for Semaphore

impl Send for Semaphore

impl Sync for Semaphore

impl Unpin for Semaphore

impl !UnwindSafe for Semaphore

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized
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impl<T> Borrow<T> for T where
    T: ?Sized
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impl<T> BorrowMut<T> for T where
    T: ?Sized
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impl<T> From<T> for T[src]

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

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.