[−][src]Struct tokio_sync::semaphore::Permit
A semaphore permit
Tracks the lifecycle of a semaphore permit.
An instance of Permit
is intended to be used with a single instance of
Semaphore
. Using a single instance of Permit
with multiple semaphore
instances will result in unexpected behavior.
Permit
does not release the permit back to the semaphore on drop. It
is the user's responsibility to ensure that Permit::release
is called
before dropping the permit.
Methods
impl Permit
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pub fn new() -> Permit
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Create a new Permit
.
The permit begins in the "unacquired" state.
Examples
use tokio_sync::semaphore::Permit; let permit = Permit::new(); assert!(!permit.is_acquired());
pub fn is_acquired(&self) -> bool
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Returns true if the permit has been acquired
pub fn poll_acquire(&mut self, semaphore: &Semaphore) -> Poll<(), AcquireError>
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Try to acquire the permit. If no permits are available, the current task is notified once a new permit becomes available.
pub fn try_acquire(
&mut self,
semaphore: &Semaphore
) -> Result<(), TryAcquireError>
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&mut self,
semaphore: &Semaphore
) -> Result<(), TryAcquireError>
Try to acquire the permit.
pub fn release(&mut self, semaphore: &Semaphore)
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Release a permit back to the semaphore
pub fn forget(&mut self)
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Forget the permit without releasing it back to the semaphore.
After calling forget
, poll_acquire
is able to acquire new permit
from the sempahore.
Repeatedly calling forget
without associated calls to add_permit
will result in the semaphore losing all permits.
Trait Implementations
Auto Trait Implementations
impl Send for Permit
impl Unpin for Permit
impl Sync for Permit
impl !UnwindSafe for Permit
impl !RefUnwindSafe for Permit
Blanket Implementations
impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> From<T> for T
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,