Crate async_lock

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Expand description

Async synchronization primitives.

This crate provides the following primitives:

  • Barrier - enables tasks to synchronize all together at the same time.
  • Mutex - a mutual exclusion lock.
  • RwLock - a reader-writer lock, allowing any number of readers or a single writer.
  • Semaphore - limits the number of concurrent operations.

§Relationship with std::sync

In general, you should consider using std::sync types over types from this crate.

There are two primary use cases for types from this crate:

  • You need to use a synchronization primitive in a no_std environment.
  • You need to hold a lock across an .await point. (Holding an std::sync lock guard across an .await will make your future non-Send, and is also highly likely to cause deadlocks.)

If you already use libstd and you aren’t holding locks across await points (there is a Clippy lint called await_holding_lock that emits warnings for this scenario), you should consider std::sync instead of this crate. Those types are optimized for the currently running operating system, are less complex and are generally much faster.

In contrast, async-lock’s notification system uses std::sync::Mutex under the hood if the std feature is enabled, and will fall back to a significantly slower strategy if it is not. So, there are few cases where async-lock is a win for performance over std::sync.

Modules§

  • Named futures for use with async_lock primitives.

Structs§