# Struct std::sync::atomic::AtomicPtr [−] [src]

    pub struct AtomicPtr<T> {
        // some fields omitted
    }

1.0.0

A raw pointer type which can be safely shared between threads.

## Methods

### `impl<T> AtomicPtr<T>`

#### `const fn new(p: *mut T) -> AtomicPtr<T>`

Creates a new `AtomicPtr`.

# Examples

fn main() { use std::sync::atomic::AtomicPtr; let ptr = &mut 5; let atomic_ptr = AtomicPtr::new(ptr); }

    use std::sync::atomic::AtomicPtr;

    let ptr = &mut 5;
    let atomic_ptr  = AtomicPtr::new(ptr);

#### `fn load(&self, order: Ordering) -> *mut T`

Loads a value from the pointer.

`load` takes an `Ordering` argument which describes the memory ordering of this operation.

# Panics

Panics if `order` is `Release` or `AcqRel`.

# Examples

fn main() { use std::sync::atomic::{AtomicPtr, Ordering}; let ptr = &mut 5; let some_ptr = AtomicPtr::new(ptr); let value = some_ptr.load(Ordering::Relaxed); }

    use std::sync::atomic::{AtomicPtr, Ordering};

    let ptr = &mut 5;
    let some_ptr  = AtomicPtr::new(ptr);

    let value = some_ptr.load(Ordering::Relaxed);

#### `fn store(&self, ptr: *mut T, order: Ordering)`

Stores a value into the pointer.

`store` takes an `Ordering` argument which describes the memory ordering of this operation.

# Examples

fn main() { use std::sync::atomic::{AtomicPtr, Ordering}; let ptr = &mut 5; let some_ptr = AtomicPtr::new(ptr); let other_ptr = &mut 10; some_ptr.store(other_ptr, Ordering::Relaxed); }

    use std::sync::atomic::{AtomicPtr, Ordering};

    let ptr = &mut 5;
    let some_ptr  = AtomicPtr::new(ptr);

    let other_ptr = &mut 10;

    some_ptr.store(other_ptr, Ordering::Relaxed);

# Panics

Panics if `order` is `Acquire` or `AcqRel`.

#### `fn swap(&self, ptr: *mut T, order: Ordering) -> *mut T`

Stores a value into the pointer, returning the old value.

`swap` takes an `Ordering` argument which describes the memory ordering of this operation.

# Examples

fn main() { use std::sync::atomic::{AtomicPtr, Ordering}; let ptr = &mut 5; let some_ptr = AtomicPtr::new(ptr); let other_ptr = &mut 10; let value = some_ptr.swap(other_ptr, Ordering::Relaxed); }

    use std::sync::atomic::{AtomicPtr, Ordering};

    let ptr = &mut 5;
    let some_ptr  = AtomicPtr::new(ptr);

    let other_ptr = &mut 10;

    let value = some_ptr.swap(other_ptr, Ordering::Relaxed);

#### `fn compare_and_swap(&self, current: *mut T, new: *mut T, order: Ordering) -> *mut T`

Stores a value into the pointer if the current value is the same as the `current` value.

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

`compare_and_swap` also takes an `Ordering` argument which describes the memory ordering of this operation.

# Examples

fn main() { use std::sync::atomic::{AtomicPtr, Ordering}; let ptr = &mut 5; let some_ptr = AtomicPtr::new(ptr); let other_ptr = &mut 10; let another_ptr = &mut 10; let value = some_ptr.compare_and_swap(other_ptr, another_ptr, Ordering::Relaxed); }

    use std::sync::atomic::{AtomicPtr, Ordering};

    let ptr = &mut 5;
    let some_ptr  = AtomicPtr::new(ptr);

    let other_ptr   = &mut 10;
    let another_ptr = &mut 10;

    let value = some_ptr.compare_and_swap(other_ptr, another_ptr, Ordering::Relaxed);

#### `fn compare_exchange(&self, current: *mut T, new: *mut T, success: Ordering, failure: Ordering) -> Result<*mut T, *mut T>`

Unstable (`extended_compare_and_swap` #31767)

: recently added

Stores a value into the pointer if the current value is the same as the `current` value.

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 `new`.

`compare_exchange` takes two `Ordering` arguments to describe the memory ordering of this operation. The first describes the required ordering if the operation succeeds while the second describes the required ordering when the operation fails. The failure ordering can't be `Acquire` or `AcqRel` and must be equivalent or weaker than the success ordering.

# Examples

#![feature(extended_compare_and_swap)] fn main() { use std::sync::atomic::{AtomicPtr, Ordering}; let ptr = &mut 5; let some_ptr = AtomicPtr::new(ptr); let other_ptr = &mut 10; let another_ptr = &mut 10; let value = some_ptr.compare_exchange(other_ptr, another_ptr, Ordering::SeqCst, Ordering::Relaxed); }

    use std::sync::atomic::{AtomicPtr, Ordering};

    let ptr = &mut 5;
    let some_ptr  = AtomicPtr::new(ptr);

    let other_ptr   = &mut 10;
    let another_ptr = &mut 10;

    let value = some_ptr.compare_exchange(other_ptr, another_ptr,
                                          Ordering::SeqCst, Ordering::Relaxed);

#### `fn compare_exchange_weak(&self, current: *mut T, new: *mut T, success: Ordering, failure: Ordering) -> Result<*mut T, *mut T>`

Unstable (`extended_compare_and_swap` #31767)

: recently added

Stores a value into the pointer if the current value is the same as the `current` value.

Unlike `compare_exchange`, this function is allowed to spuriously fail even when the comparison succeeds, which can result in more efficient code on some platforms. The return value is a result indicating whether the new value was written and containing the previous value.

`compare_exchange_weak` takes two `Ordering` arguments to describe the memory ordering of this operation. The first describes the required ordering if the operation succeeds while the second describes the required ordering when the operation fails. The failure ordering can't be `Acquire` or `AcqRel` and must be equivalent or weaker than the success ordering.

# Examples

#![feature(extended_compare_and_swap)] fn main() { use std::sync::atomic::{AtomicPtr, Ordering}; let some_ptr = AtomicPtr::new(&mut 5); let new = &mut 10; let mut old = some_ptr.load(Ordering::Relaxed); loop { match some_ptr.compare_exchange_weak(old, new, Ordering::SeqCst, Ordering::Relaxed) { Ok(_) => break, Err(x) => old = x, } } }

    use std::sync::atomic::{AtomicPtr, Ordering};

    let some_ptr = AtomicPtr::new(&mut 5);

    let new = &mut 10;
    let mut old = some_ptr.load(Ordering::Relaxed);
    loop {
        match some_ptr.compare_exchange_weak(old, new, Ordering::SeqCst, Ordering::Relaxed) {
            Ok(_) => break,
            Err(x) => old = x,
        }
    }

## Trait Implementations

### `impl<T> Default for AtomicPtr<T>`

#### `fn default() -> AtomicPtr<T>`

### `impl<T> Debug for AtomicPtr<T>`1.3.0

#### `fn fmt(&self, f: &mut Formatter) -> Result<(), Error>`

### `impl<T> Sync for AtomicPtr<T>`

### `impl<T> Send for AtomicPtr<T>`

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