Crate spin

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Expand description

This crate provides spin-based versions of the primitives in std::sync and std::lazy. Because synchronization is done through spinning, the primitives are suitable for use in no_std environments.


  • Mutex, RwLock, Once/SyncOnceCell, and SyncLazy equivalents

  • Support for no_std environments

  • lock_api compatibility

  • Upgradeable RwLock guards

  • Guards can be sent and shared between threads

  • Guard leaking

  • Ticket locks

  • Different strategies for dealing with contention

Relationship with std::sync

While spin is not a drop-in replacement for std::sync (and should not be considered as such) an effort is made to keep this crate reasonably consistent with std::sync.

Many of the types defined in this crate have ‘additional capabilities’ when compared to std::sync:

Conversely, the types in this crate do not have some of the features std::sync has:

Feature flags

The crate comes with a few feature flags that you may wish to use.

  • lock_api enables support for lock_api

  • ticket_mutex uses a ticket lock for the implementation of Mutex

  • fair_mutex enables a fairer implementation of Mutex that uses eventual fairness to avoid starvation

  • std enables support for thread yielding instead of spinning



  • barrierbarrier
    Synchronization primitive allowing multiple threads to synchronize the beginning of some computation.
  • lazylazy
    Synchronization primitives for lazy evaluation.
  • lock_apilock_api
    Spin synchronisation primitives, but compatible with lock_api.
  • mutexmutex
    Locks that have the same behaviour as a mutex.
  • onceonce
    Synchronization primitives for one-time evaluation.
  • Strategies that determine the behaviour of locks when encountering contention.
  • rwlockrwlock
    A lock that provides data access to either one writer or many readers.

Type Definitions