Struct AtomicFlag 

pub struct AtomicFlag(/* private fields */);

An atomic flag type intended to be backed by performance-optimal integer type.

The backing integer type is an implementation detail; it may vary by architecture and change in the future.

AtomicFlag is generally preferable to Atomic<bool> when you need read-modify-write (RMW) operations (e.g. Atomic::xchg()/Atomic::cmpxchg()) or when Atomic<bool> does not save memory due to padding. On some architectures that do not support byte-sized atomic RMW operations, RMW operations on Atomic<bool> are slower.

If you only use Atomic::load()/Atomic::store(), Atomic<bool> is fine.

Examples

use kernel::sync::atomic::{AtomicFlag, Relaxed};

let flag = AtomicFlag::new(false);
assert_eq!(false, flag.load(Relaxed));
flag.store(true, Relaxed);
assert_eq!(true, flag.load(Relaxed));

Implementations

impl AtomicFlag

pub const fn new(b: bool) -> Self

Creates a new atomic flag.

pub fn get_mut(&mut self) -> &mut bool

Returns a mutable reference to the underlying flag as a bool.

This is safe because the mutable reference of the atomic flag guarantees exclusive access.

Examples

use kernel::sync::atomic::{AtomicFlag, Relaxed};

let mut atomic_flag = AtomicFlag::new(false);
assert_eq!(false, atomic_flag.load(Relaxed));
*atomic_flag.get_mut() = true;
assert_eq!(true, atomic_flag.load(Relaxed));

pub fn load<Ordering: AcquireOrRelaxed>(&self, o: Ordering) -> bool

Loads the value from the atomic flag.

pub fn store<Ordering: ReleaseOrRelaxed>(&self, v: bool, o: Ordering)

Stores a value to the atomic flag.

pub fn xchg<Ordering: Ordering>(&self, new: bool, o: Ordering) -> bool

Stores a value to the atomic flag and returns the previous value.

pub fn cmpxchg<Ordering: Ordering>( &self, old: bool, new: bool, o: Ordering, ) -> Result<bool, bool>

Store a value to the atomic flag if the current value is equal to old.