Struct crossbeam_utils::atomic::AtomicCell

#[repr(transparent)]
pub struct AtomicCell<T: ?Sized> { /* fields omitted */ }

A thread-safe mutable memory location.

This type is equivalent to Cell, except it can also be shared among multiple threads.

Operations on AtomicCells use atomic instructions whenever possible, and synchronize using global locks otherwise. You can call AtomicCell::<T>::is_lock_free() to check whether atomic instructions or locks will be used.

Atomic loads use the Acquire ordering and atomic stores use the Release ordering.

Implementations

impl<T> AtomicCell<T>

pub const fn new(val: T) -> AtomicCell<T>

Creates a new atomic cell initialized with val.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7);

pub fn into_inner(self) -> T

Consumes the atomic and returns the contained value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7);
let v = a.into_inner();

assert_eq!(v, 7);

pub const fn is_lock_free() -> bool

Returns true if operations on values of this type are lock-free.

If the compiler or the platform doesn’t support the necessary atomic instructions, AtomicCell<T> will use global locks for every potentially concurrent atomic operation.

Examples

use crossbeam_utils::atomic::AtomicCell;

// This type is internally represented as `AtomicUsize` so we can just use atomic
// operations provided by it.
assert_eq!(AtomicCell::<usize>::is_lock_free(), true);

// A wrapper struct around `isize`.
struct Foo {
    bar: isize,
}
// `AtomicCell<Foo>` will be internally represented as `AtomicIsize`.
assert_eq!(AtomicCell::<Foo>::is_lock_free(), true);

// Operations on zero-sized types are always lock-free.
assert_eq!(AtomicCell::<()>::is_lock_free(), true);

// Very large types cannot be represented as any of the standard atomic types, so atomic
// operations on them will have to use global locks for synchronization.
assert_eq!(AtomicCell::<[u8; 1000]>::is_lock_free(), false);

pub fn store(&self, val: T)

Stores val into the atomic cell.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7);

assert_eq!(a.load(), 7);
a.store(8);
assert_eq!(a.load(), 8);

pub fn swap(&self, val: T) -> T

Stores val into the atomic cell and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7);

assert_eq!(a.load(), 7);
assert_eq!(a.swap(8), 7);
assert_eq!(a.load(), 8);

impl<T: ?Sized> AtomicCell<T>

pub fn as_ptr(&self) -> *mut T

Returns a raw pointer to the underlying data in this atomic cell.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(5);

let ptr = a.as_ptr();

impl<T: Default> AtomicCell<T>

pub fn take(&self) -> T

Takes the value of the atomic cell, leaving Default::default() in its place.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(5);
let five = a.take();

assert_eq!(five, 5);
assert_eq!(a.into_inner(), 0);

impl<T: Copy> AtomicCell<T>

pub fn load(&self) -> T

Loads a value from the atomic cell.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7);

assert_eq!(a.load(), 7);

impl<T: Copy + Eq> AtomicCell<T>

pub fn compare_and_swap(&self, current: T, new: T) -> T

👎 Deprecated:

Use compare_exchange instead

If the current value equals current, stores new into the atomic cell.

The return value is always the previous value. If it is equal to current, then the value was updated.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(1);

assert_eq!(a.compare_and_swap(2, 3), 1);
assert_eq!(a.load(), 1);

assert_eq!(a.compare_and_swap(1, 2), 1);
assert_eq!(a.load(), 2);

pub fn compare_exchange(&self, current: T, new: T) -> Result<T, T>

If the current value equals current, stores new into the atomic cell.

The return value is a result indicating whether the new value was written and containing the previous value. On success this value is guaranteed to be equal to current.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(1);

assert_eq!(a.compare_exchange(2, 3), Err(1));
assert_eq!(a.load(), 1);

assert_eq!(a.compare_exchange(1, 2), Ok(1));
assert_eq!(a.load(), 2);

pub fn fetch_update<F>(&self, f: F) -> Result<T, T> where
    F: FnMut(T) -> Option<T>, 

Fetches the value, and applies a function to it that returns an optional new value. Returns a Result of Ok(previous_value) if the function returned Some(_), else Err(previous_value).

Note: This may call the function multiple times if the value has been changed from other threads in the meantime, as long as the function returns Some(_), but the function will have been applied only once to the stored value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7);
assert_eq!(a.fetch_update(|_| None), Err(7));
assert_eq!(a.fetch_update(|a| Some(a + 1)), Ok(7));
assert_eq!(a.fetch_update(|a| Some(a + 1)), Ok(8));
assert_eq!(a.load(), 9);

impl AtomicCell<u8>

pub fn fetch_add(&self, val: u8) -> u8

Increments the current value by val and returns the previous value.

The addition wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u8);

assert_eq!(a.fetch_add(3), 7);
assert_eq!(a.load(), 10);

pub fn fetch_sub(&self, val: u8) -> u8

Decrements the current value by val and returns the previous value.

The subtraction wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u8);

assert_eq!(a.fetch_sub(3), 7);
assert_eq!(a.load(), 4);

pub fn fetch_and(&self, val: u8) -> u8

Applies bitwise “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u8);

assert_eq!(a.fetch_and(3), 7);
assert_eq!(a.load(), 3);

pub fn fetch_or(&self, val: u8) -> u8

Applies bitwise “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u8);

assert_eq!(a.fetch_or(16), 7);
assert_eq!(a.load(), 23);

pub fn fetch_xor(&self, val: u8) -> u8

Applies bitwise “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u8);

assert_eq!(a.fetch_xor(2), 7);
assert_eq!(a.load(), 5);

impl AtomicCell<i8>

pub fn fetch_add(&self, val: i8) -> i8

Increments the current value by val and returns the previous value.

The addition wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i8);

assert_eq!(a.fetch_add(3), 7);
assert_eq!(a.load(), 10);

pub fn fetch_sub(&self, val: i8) -> i8

Decrements the current value by val and returns the previous value.

The subtraction wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i8);

assert_eq!(a.fetch_sub(3), 7);
assert_eq!(a.load(), 4);

pub fn fetch_and(&self, val: i8) -> i8

Applies bitwise “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i8);

assert_eq!(a.fetch_and(3), 7);
assert_eq!(a.load(), 3);

pub fn fetch_or(&self, val: i8) -> i8

Applies bitwise “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i8);

assert_eq!(a.fetch_or(16), 7);
assert_eq!(a.load(), 23);

pub fn fetch_xor(&self, val: i8) -> i8

Applies bitwise “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i8);

assert_eq!(a.fetch_xor(2), 7);
assert_eq!(a.load(), 5);

impl AtomicCell<u16>

pub fn fetch_add(&self, val: u16) -> u16

Increments the current value by val and returns the previous value.

The addition wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u16);

assert_eq!(a.fetch_add(3), 7);
assert_eq!(a.load(), 10);

pub fn fetch_sub(&self, val: u16) -> u16

Decrements the current value by val and returns the previous value.

The subtraction wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u16);

assert_eq!(a.fetch_sub(3), 7);
assert_eq!(a.load(), 4);

pub fn fetch_and(&self, val: u16) -> u16

Applies bitwise “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u16);

assert_eq!(a.fetch_and(3), 7);
assert_eq!(a.load(), 3);

pub fn fetch_or(&self, val: u16) -> u16

Applies bitwise “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u16);

assert_eq!(a.fetch_or(16), 7);
assert_eq!(a.load(), 23);

pub fn fetch_xor(&self, val: u16) -> u16

Applies bitwise “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u16);

assert_eq!(a.fetch_xor(2), 7);
assert_eq!(a.load(), 5);

impl AtomicCell<i16>

pub fn fetch_add(&self, val: i16) -> i16

Increments the current value by val and returns the previous value.

The addition wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i16);

assert_eq!(a.fetch_add(3), 7);
assert_eq!(a.load(), 10);

pub fn fetch_sub(&self, val: i16) -> i16

Decrements the current value by val and returns the previous value.

The subtraction wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i16);

assert_eq!(a.fetch_sub(3), 7);
assert_eq!(a.load(), 4);

pub fn fetch_and(&self, val: i16) -> i16

Applies bitwise “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i16);

assert_eq!(a.fetch_and(3), 7);
assert_eq!(a.load(), 3);

pub fn fetch_or(&self, val: i16) -> i16

Applies bitwise “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i16);

assert_eq!(a.fetch_or(16), 7);
assert_eq!(a.load(), 23);

pub fn fetch_xor(&self, val: i16) -> i16

Applies bitwise “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i16);

assert_eq!(a.fetch_xor(2), 7);
assert_eq!(a.load(), 5);

impl AtomicCell<u32>

pub fn fetch_add(&self, val: u32) -> u32

Increments the current value by val and returns the previous value.

The addition wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u32);

assert_eq!(a.fetch_add(3), 7);
assert_eq!(a.load(), 10);

pub fn fetch_sub(&self, val: u32) -> u32

Decrements the current value by val and returns the previous value.

The subtraction wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u32);

assert_eq!(a.fetch_sub(3), 7);
assert_eq!(a.load(), 4);

pub fn fetch_and(&self, val: u32) -> u32

Applies bitwise “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u32);

assert_eq!(a.fetch_and(3), 7);
assert_eq!(a.load(), 3);

pub fn fetch_or(&self, val: u32) -> u32

Applies bitwise “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u32);

assert_eq!(a.fetch_or(16), 7);
assert_eq!(a.load(), 23);

pub fn fetch_xor(&self, val: u32) -> u32

Applies bitwise “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u32);

assert_eq!(a.fetch_xor(2), 7);
assert_eq!(a.load(), 5);

impl AtomicCell<i32>

pub fn fetch_add(&self, val: i32) -> i32

Increments the current value by val and returns the previous value.

The addition wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i32);

assert_eq!(a.fetch_add(3), 7);
assert_eq!(a.load(), 10);

pub fn fetch_sub(&self, val: i32) -> i32

Decrements the current value by val and returns the previous value.

The subtraction wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i32);

assert_eq!(a.fetch_sub(3), 7);
assert_eq!(a.load(), 4);

pub fn fetch_and(&self, val: i32) -> i32

Applies bitwise “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i32);

assert_eq!(a.fetch_and(3), 7);
assert_eq!(a.load(), 3);

pub fn fetch_or(&self, val: i32) -> i32

Applies bitwise “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i32);

assert_eq!(a.fetch_or(16), 7);
assert_eq!(a.load(), 23);

pub fn fetch_xor(&self, val: i32) -> i32

Applies bitwise “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i32);

assert_eq!(a.fetch_xor(2), 7);
assert_eq!(a.load(), 5);

impl AtomicCell<u64>

pub fn fetch_add(&self, val: u64) -> u64

Increments the current value by val and returns the previous value.

The addition wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u64);

assert_eq!(a.fetch_add(3), 7);
assert_eq!(a.load(), 10);

pub fn fetch_sub(&self, val: u64) -> u64

Decrements the current value by val and returns the previous value.

The subtraction wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u64);

assert_eq!(a.fetch_sub(3), 7);
assert_eq!(a.load(), 4);

pub fn fetch_and(&self, val: u64) -> u64

Applies bitwise “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u64);

assert_eq!(a.fetch_and(3), 7);
assert_eq!(a.load(), 3);

pub fn fetch_or(&self, val: u64) -> u64

Applies bitwise “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u64);

assert_eq!(a.fetch_or(16), 7);
assert_eq!(a.load(), 23);

pub fn fetch_xor(&self, val: u64) -> u64

Applies bitwise “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7u64);

assert_eq!(a.fetch_xor(2), 7);
assert_eq!(a.load(), 5);

impl AtomicCell<i64>

pub fn fetch_add(&self, val: i64) -> i64

Increments the current value by val and returns the previous value.

The addition wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i64);

assert_eq!(a.fetch_add(3), 7);
assert_eq!(a.load(), 10);

pub fn fetch_sub(&self, val: i64) -> i64

Decrements the current value by val and returns the previous value.

The subtraction wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i64);

assert_eq!(a.fetch_sub(3), 7);
assert_eq!(a.load(), 4);

pub fn fetch_and(&self, val: i64) -> i64

Applies bitwise “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i64);

assert_eq!(a.fetch_and(3), 7);
assert_eq!(a.load(), 3);

pub fn fetch_or(&self, val: i64) -> i64

Applies bitwise “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i64);

assert_eq!(a.fetch_or(16), 7);
assert_eq!(a.load(), 23);

pub fn fetch_xor(&self, val: i64) -> i64

Applies bitwise “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7i64);

assert_eq!(a.fetch_xor(2), 7);
assert_eq!(a.load(), 5);

impl AtomicCell<usize>

pub fn fetch_add(&self, val: usize) -> usize

Increments the current value by val and returns the previous value.

The addition wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7usize);

assert_eq!(a.fetch_add(3), 7);
assert_eq!(a.load(), 10);

pub fn fetch_sub(&self, val: usize) -> usize

Decrements the current value by val and returns the previous value.

The subtraction wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7usize);

assert_eq!(a.fetch_sub(3), 7);
assert_eq!(a.load(), 4);

pub fn fetch_and(&self, val: usize) -> usize

Applies bitwise “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7usize);

assert_eq!(a.fetch_and(3), 7);
assert_eq!(a.load(), 3);

pub fn fetch_or(&self, val: usize) -> usize

Applies bitwise “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7usize);

assert_eq!(a.fetch_or(16), 7);
assert_eq!(a.load(), 23);

pub fn fetch_xor(&self, val: usize) -> usize

Applies bitwise “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7usize);

assert_eq!(a.fetch_xor(2), 7);
assert_eq!(a.load(), 5);

impl AtomicCell<isize>

pub fn fetch_add(&self, val: isize) -> isize

Increments the current value by val and returns the previous value.

The addition wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7isize);

assert_eq!(a.fetch_add(3), 7);
assert_eq!(a.load(), 10);

pub fn fetch_sub(&self, val: isize) -> isize

Decrements the current value by val and returns the previous value.

The subtraction wraps on overflow.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7isize);

assert_eq!(a.fetch_sub(3), 7);
assert_eq!(a.load(), 4);

pub fn fetch_and(&self, val: isize) -> isize

Applies bitwise “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7isize);

assert_eq!(a.fetch_and(3), 7);
assert_eq!(a.load(), 3);

pub fn fetch_or(&self, val: isize) -> isize

Applies bitwise “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7isize);

assert_eq!(a.fetch_or(16), 7);
assert_eq!(a.load(), 23);

pub fn fetch_xor(&self, val: isize) -> isize

Applies bitwise “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(7isize);

assert_eq!(a.fetch_xor(2), 7);
assert_eq!(a.load(), 5);

impl AtomicCell<bool>

pub fn fetch_and(&self, val: bool) -> bool

Applies logical “and” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(true);

assert_eq!(a.fetch_and(true), true);
assert_eq!(a.load(), true);

assert_eq!(a.fetch_and(false), true);
assert_eq!(a.load(), false);

pub fn fetch_or(&self, val: bool) -> bool

Applies logical “or” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(false);

assert_eq!(a.fetch_or(false), false);
assert_eq!(a.load(), false);

assert_eq!(a.fetch_or(true), false);
assert_eq!(a.load(), true);

pub fn fetch_xor(&self, val: bool) -> bool

Applies logical “xor” to the current value and returns the previous value.

Examples

use crossbeam_utils::atomic::AtomicCell;

let a = AtomicCell::new(true);

assert_eq!(a.fetch_xor(false), true);
assert_eq!(a.load(), true);

assert_eq!(a.fetch_xor(true), true);
assert_eq!(a.load(), false);

Trait Implementations

impl<T: Copy + Debug> Debug for AtomicCell<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Default> Default for AtomicCell<T>

fn default() -> AtomicCell<T>

Returns the “default value” for a type.

impl<T> From<T> for AtomicCell<T>

fn from(val: T) -> AtomicCell<T>

Performs the conversion.

impl<T> RefUnwindSafe for AtomicCell<T>

impl<T: Send> Send for AtomicCell<T>

impl<T: Send> Sync for AtomicCell<T>

impl<T> UnwindSafe for AtomicCell<T>