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Spin-based synchronization primitives.

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

Before deciding to use spin, we recommend reading this superb blog post by @matklad that discusses the pros and cons of spinlocks. If you have access to std, it's likely that the primitives in std::sync will serve you better except in very specific circumstances.

Features

Usage

Include the following under the [dependencies] section in your Cargo.toml file.

spin = "x.y"

Example

When calling lock on a Mutex you will get a guard value that provides access to the data. When this guard is dropped, the mutex will become available again.

extern crate spin;
use std::{sync::Arc, thread};

fn main() {
    let counter = Arc::new(spin::Mutex::new(0));

    let thread = thread::spawn({
        let counter = counter.clone();
        move || {
            for _ in 0..100 {
                *counter.lock() += 1;
            }
        }
    });

    for _ in 0..100 {
        *counter.lock() += 1;
    }

    thread.join().unwrap();

    assert_eq!(*counter.lock(), 200);
}

Feature flags

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

Remarks

It is often desirable to have a lock shared between threads. Wrapping the lock in an std::sync::Arc is route through which this might be achieved.

Locks provide zero-overhead access to their data when accessed through a mutable reference by using their get_mut methods.

The behaviour of these lock is similar to their namesakes in std::sync. they differ on the following:

Many of the feature flags listed above are enabled by default. If you're writing a library, we recommend disabling those that you don't use to avoid increasing compilation time for your crate's users. You can do this like so:

[dependencies]
spin = { version = "x.y", default-features = false, features = [...] }

Minimum Safe Rust Version (MSRV)

This crate is guaranteed to compile on a Minimum Safe Rust Version (MSRV) of 1.38.0 and above. This version will not be changed without a minor version bump.

License

spin is distributed under the MIT License, (See LICENSE).