Module tokio_sync::semaphore

Thread-safe, asynchronous counting semaphore.

A Semaphore instance holds a set of permits. Permits are used to synchronize access to a shared resource.

Before accessing the shared resource, callers acquire a permit from the semaphore. Once the permit is acquired, the caller then enters the critical section. If no permits are available, then acquiring the semaphore returns NotReady. The task is notified once a permit becomes available.

Structs

AcquireError	Error returned by Permit::poll_acquire.
Permit	A semaphore permit
Semaphore	Futures-aware semaphore.
TryAcquireError	Error returned by Permit::try_acquire.