Struct tokio::sync::Semaphore

pub struct Semaphore { /* fields omitted */ }

This is supported on feature="sync" only.

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.

Methods

impl Semaphore

pub fn new(permits: usize) -> Self

This is supported on feature="sync" only.

Creates a new semaphore with the initial number of permits

pub fn available_permits(&self) -> usize

This is supported on feature="sync" only.

Returns the current number of available permits

pub fn add_permits(&self, n: usize)

This is supported on feature="sync" only.

Adds n new permits to the semaphore.

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

This is supported on feature="sync" only.

Acquires permit from the semaphore

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

This is supported on feature="sync" only.

Tries to acquire a permit form the semaphore

Trait Implementations

impl Debug for Semaphore

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.