# Struct core::sync::atomic::AtomicI32 1.34.0[−][src]

    #[repr(C, align(4))]pub struct AtomicI32 { /* fields omitted */ }

An integer type which can be safely shared between threads.

This type has the same in-memory representation as the underlying integer type, `i32`. For more about the differences between atomic types and non-atomic types as well as information about the portability of this type, please see the module-level documentation.

Note: This type is only available on platforms that support atomic loads and stores of `i32`.

## Implementations

### `impl AtomicI32`[src]

#### `pub const fn new(v: i32) -> Self` 1.34.0 (const: 1.34.0)[src]

Creates a new atomic integer.

# Examples

    use std::sync::atomic::AtomicI32;

    let atomic_forty_two = AtomicI32::new(42);

Run

#### `pub fn get_mut(&mut self) -> &mut i32`[src]

Returns a mutable reference to the underlying integer.

This is safe because the mutable reference guarantees that no other threads are concurrently accessing the atomic data.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let mut some_var = AtomicI32::new(10);
    assert_eq!(*some_var.get_mut(), 10);
    *some_var.get_mut() = 5;
    assert_eq!(some_var.load(Ordering::SeqCst), 5);

Run

#### `pub fn from_mut(v: &mut i32) -> &Self`[src]

🔬 This is a nightly-only experimental API. (`atomic_from_mut` #76314)

Get atomic access to a `&mut i32`.

Note: This function is only available on targets where `i32` has an alignment of 4 bytes.

# Examples

    #![feature(atomic_from_mut)]
    use std::sync::atomic::{AtomicI32, Ordering};

    let mut some_int = 123;
    let a = AtomicI32::from_mut(&mut some_int);
    a.store(100, Ordering::Relaxed);
    assert_eq!(some_int, 100);

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#### `pub fn into_inner(self) -> i32`[src]

Consumes the atomic and returns the contained value.

This is safe because passing `self` by value guarantees that no other threads are concurrently accessing the atomic data.

# Examples

    use std::sync::atomic::AtomicI32;

    let some_var = AtomicI32::new(5);
    assert_eq!(some_var.into_inner(), 5);

Run

#### `pub fn load(&self, order: Ordering) -> i32`[src]

Loads a value from the atomic integer.

`load` takes an `Ordering` argument which describes the memory ordering of this operation. Possible values are `SeqCst`, `Acquire` and `Relaxed`.

# Panics

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

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let some_var = AtomicI32::new(5);

    assert_eq!(some_var.load(Ordering::Relaxed), 5);

Run

#### `pub fn store(&self, val: i32, order: Ordering)`[src]

Stores a value into the atomic integer.

`store` takes an `Ordering` argument which describes the memory ordering of this operation. Possible values are `SeqCst`, `Release` and `Relaxed`.

# Panics

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

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let some_var = AtomicI32::new(5);

    some_var.store(10, Ordering::Relaxed);
    assert_eq!(some_var.load(Ordering::Relaxed), 10);

Run

#### `pub fn swap(&self, val: i32, order: Ordering) -> i32`[src]

Stores a value into the atomic integer, returning the previous value.

`swap` takes an `Ordering` argument which describes the memory ordering of this operation. All ordering modes are possible. Note that using `Acquire` makes the store part of this operation `Relaxed`, and using `Release` makes the load part `Relaxed`.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let some_var = AtomicI32::new(5);

    assert_eq!(some_var.swap(10, Ordering::Relaxed), 5);

Run

#### `pub fn compare_and_swap(&self, current: i32, new: i32, order: Ordering) -> i32`[src]

👎 Deprecated since 1.50.0:

Use `compare_exchange` or `compare_exchange_weak` instead

Stores a value into the atomic integer 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. Notice that even when using `AcqRel`, the operation might fail and hence just perform an `Acquire` load, but not have `Release` semantics. Using `Acquire` makes the store part of this operation `Relaxed` if it happens, and using `Release` makes the load part `Relaxed`.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Migrating to `compare_exchange` and `compare_exchange_weak`

`compare_and_swap` is equivalent to `compare_exchange` with the following mapping for memory orderings:

Original | Success | Failure
--- | --- | ---
Relaxed | Relaxed | Relaxed
Acquire | Acquire | Acquire
Release | Release | Relaxed
AcqRel | AcqRel | Acquire
SeqCst | SeqCst | SeqCst

`compare_exchange_weak` is allowed to fail spuriously even when the comparison succeeds, which allows the compiler to generate better assembly code when the compare and swap is used in a loop.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let some_var = AtomicI32::new(5);

    assert_eq!(some_var.compare_and_swap(5, 10, Ordering::Relaxed), 5);
    assert_eq!(some_var.load(Ordering::Relaxed), 10);

    assert_eq!(some_var.compare_and_swap(6, 12, Ordering::Relaxed), 10);
    assert_eq!(some_var.load(Ordering::Relaxed), 10);

Run

#### `pub fn compare_exchange(
&self,
current: i32,
new: i32,
success: Ordering,
failure: Ordering
) -> Result<i32, i32>`[src]

Stores a value into the atomic integer 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 `current`.

`compare_exchange` takes two `Ordering` arguments to describe the memory ordering of this operation. `success` describes the required ordering for the read-modify-write operation that takes place if the comparison with `current` succeeds. `failure` describes the required ordering for the load operation that takes place when the comparison fails. Using `Acquire` as success ordering makes the store part of this operation `Relaxed`, and using `Release` makes the successful load `Relaxed`. The failure ordering can only be `SeqCst`, `Acquire` or `Relaxed` and must be equivalent to or weaker than the success ordering.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let some_var = AtomicI32::new(5);

    assert_eq!(some_var.compare_exchange(5, 10,
                                         Ordering::Acquire,
                                         Ordering::Relaxed),
               Ok(5));
    assert_eq!(some_var.load(Ordering::Relaxed), 10);

    assert_eq!(some_var.compare_exchange(6, 12,
                                         Ordering::SeqCst,
                                         Ordering::Acquire),
               Err(10));
    assert_eq!(some_var.load(Ordering::Relaxed), 10);

Run

#### `pub fn compare_exchange_weak(
&self,
current: i32,
new: i32,
success: Ordering,
failure: Ordering
) -> Result<i32, i32>`[src]

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

Unlike `AtomicI32::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. `success` describes the required ordering for the read-modify-write operation that takes place if the comparison with `current` succeeds. `failure` describes the required ordering for the load operation that takes place when the comparison fails. Using `Acquire` as success ordering makes the store part of this operation `Relaxed`, and using `Release` makes the successful load `Relaxed`. The failure ordering can only be `SeqCst`, `Acquire` or `Relaxed` and must be equivalent to or weaker than the success ordering.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let val = AtomicI32::new(4);

    let mut old = val.load(Ordering::Relaxed);
    loop {
        let new = old * 2;
        match val.compare_exchange_weak(old, new, Ordering::SeqCst, Ordering::Relaxed) {
            Ok(_) => break,
            Err(x) => old = x,
        }
    }

Run

#### `pub fn fetch_add(&self, val: i32, order: Ordering) -> i32`[src]

Adds to the current value, returning the previous value.

This operation wraps around on overflow.

`fetch_add` takes an `Ordering` argument which describes the memory ordering of this operation. All ordering modes are possible. Note that using `Acquire` makes the store part of this operation `Relaxed`, and using `Release` makes the load part `Relaxed`.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let foo = AtomicI32::new(0);
    assert_eq!(foo.fetch_add(10, Ordering::SeqCst), 0);
    assert_eq!(foo.load(Ordering::SeqCst), 10);

Run

#### `pub fn fetch_sub(&self, val: i32, order: Ordering) -> i32`[src]

Subtracts from the current value, returning the previous value.

This operation wraps around on overflow.

`fetch_sub` takes an `Ordering` argument which describes the memory ordering of this operation. All ordering modes are possible. Note that using `Acquire` makes the store part of this operation `Relaxed`, and using `Release` makes the load part `Relaxed`.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let foo = AtomicI32::new(20);
    assert_eq!(foo.fetch_sub(10, Ordering::SeqCst), 20);
    assert_eq!(foo.load(Ordering::SeqCst), 10);

Run

#### `pub fn fetch_and(&self, val: i32, order: Ordering) -> i32`[src]

Bitwise "and" with the current value.

Performs a bitwise "and" operation on the current value and the argument `val`, and sets the new value to the result.

Returns the previous value.

`fetch_and` takes an `Ordering` argument which describes the memory ordering of this operation. All ordering modes are possible. Note that using `Acquire` makes the store part of this operation `Relaxed`, and using `Release` makes the load part `Relaxed`.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let foo = AtomicI32::new(0b101101);
    assert_eq!(foo.fetch_and(0b110011, Ordering::SeqCst), 0b101101);
    assert_eq!(foo.load(Ordering::SeqCst), 0b100001);

Run

#### `pub fn fetch_nand(&self, val: i32, order: Ordering) -> i32`[src]

Bitwise "nand" with the current value.

Performs a bitwise "nand" operation on the current value and the argument `val`, and sets the new value to the result.

Returns the previous value.

`fetch_nand` takes an `Ordering` argument which describes the memory ordering of this operation. All ordering modes are possible. Note that using `Acquire` makes the store part of this operation `Relaxed`, and using `Release` makes the load part `Relaxed`.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let foo = AtomicI32::new(0x13);
    assert_eq!(foo.fetch_nand(0x31, Ordering::SeqCst), 0x13);
    assert_eq!(foo.load(Ordering::SeqCst), !(0x13 & 0x31));

Run

#### `pub fn fetch_or(&self, val: i32, order: Ordering) -> i32`[src]

Bitwise "or" with the current value.

Performs a bitwise "or" operation on the current value and the argument `val`, and sets the new value to the result.

Returns the previous value.

`fetch_or` takes an `Ordering` argument which describes the memory ordering of this operation. All ordering modes are possible. Note that using `Acquire` makes the store part of this operation `Relaxed`, and using `Release` makes the load part `Relaxed`.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let foo = AtomicI32::new(0b101101);
    assert_eq!(foo.fetch_or(0b110011, Ordering::SeqCst), 0b101101);
    assert_eq!(foo.load(Ordering::SeqCst), 0b111111);

Run

#### `pub fn fetch_xor(&self, val: i32, order: Ordering) -> i32`[src]

Bitwise "xor" with the current value.

Performs a bitwise "xor" operation on the current value and the argument `val`, and sets the new value to the result.

Returns the previous value.

`fetch_xor` takes an `Ordering` argument which describes the memory ordering of this operation. All ordering modes are possible. Note that using `Acquire` makes the store part of this operation `Relaxed`, and using `Release` makes the load part `Relaxed`.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let foo = AtomicI32::new(0b101101);
    assert_eq!(foo.fetch_xor(0b110011, Ordering::SeqCst), 0b101101);
    assert_eq!(foo.load(Ordering::SeqCst), 0b011110);

Run

#### `pub fn fetch_update<F>(
&self,
set_order: Ordering,
fetch_order: Ordering,
f: F
) -> Result<i32, i32> where
F: FnMut(i32) -> Option<i32>,` 1.45.0[src]

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.

`fetch_update` takes two `Ordering` arguments to describe the memory ordering of this operation. The first describes the required ordering for when the operation finally succeeds while the second describes the required ordering for loads. These correspond to the success and failure orderings of `AtomicI32::compare_exchange` respectively.

Using `Acquire` as success ordering makes the store part of this operation `Relaxed`, and using `Release` makes the final successful load `Relaxed`. The (failed) load ordering can only be `SeqCst`, `Acquire` or `Relaxed` and must be equivalent to or weaker than the success ordering.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let x = AtomicI32::new(7);
    assert_eq!(x.fetch_update(Ordering::SeqCst, Ordering::SeqCst, |_| None), Err(7));
    assert_eq!(x.fetch_update(Ordering::SeqCst, Ordering::SeqCst, |x| Some(x + 1)), Ok(7));
    assert_eq!(x.fetch_update(Ordering::SeqCst, Ordering::SeqCst, |x| Some(x + 1)), Ok(8));
    assert_eq!(x.load(Ordering::SeqCst), 9);

Run

#### `pub fn fetch_max(&self, val: i32, order: Ordering) -> i32` 1.45.0[src]

Maximum with the current value.

Finds the maximum of the current value and the argument `val`, and sets the new value to the result.

Returns the previous value.

`fetch_max` takes an `Ordering` argument which describes the memory ordering of this operation. All ordering modes are possible. Note that using `Acquire` makes the store part of this operation `Relaxed`, and using `Release` makes the load part `Relaxed`.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let foo = AtomicI32::new(23);
    assert_eq!(foo.fetch_max(42, Ordering::SeqCst), 23);
    assert_eq!(foo.load(Ordering::SeqCst), 42);

Run

If you want to obtain the maximum value in one step, you can use the following:

    use std::sync::atomic::{AtomicI32, Ordering};

    let foo = AtomicI32::new(23);
    let bar = 42;
    let max_foo = foo.fetch_max(bar, Ordering::SeqCst).max(bar);
    assert!(max_foo == 42);

Run

#### `pub fn fetch_min(&self, val: i32, order: Ordering) -> i32` 1.45.0[src]

Minimum with the current value.

Finds the minimum of the current value and the argument `val`, and sets the new value to the result.

Returns the previous value.

`fetch_min` takes an `Ordering` argument which describes the memory ordering of this operation. All ordering modes are possible. Note that using `Acquire` makes the store part of this operation `Relaxed`, and using `Release` makes the load part `Relaxed`.

Note: This method is only available on platforms that support atomic operations on `i32`.

# Examples

    use std::sync::atomic::{AtomicI32, Ordering};

    let foo = AtomicI32::new(23);
    assert_eq!(foo.fetch_min(42, Ordering::Relaxed), 23);
    assert_eq!(foo.load(Ordering::Relaxed), 23);
    assert_eq!(foo.fetch_min(22, Ordering::Relaxed), 23);
    assert_eq!(foo.load(Ordering::Relaxed), 22);

Run

If you want to obtain the minimum value in one step, you can use the following:

    use std::sync::atomic::{AtomicI32, Ordering};

    let foo = AtomicI32::new(23);
    let bar = 12;
    let min_foo = foo.fetch_min(bar, Ordering::SeqCst).min(bar);
    assert_eq!(min_foo, 12);

Run

#### `pub fn as_mut_ptr(&self) -> *mut i32`[src]

🔬 This is a nightly-only experimental API. (`atomic_mut_ptr` #66893)

recently added

Returns a mutable pointer to the underlying integer.

Doing non-atomic reads and writes on the resulting integer can be a data race. This method is mostly useful for FFI, where the function signature may use `*mut i32` instead of `&AtomicI32`.

Returning an `*mut` pointer from a shared reference to this atomic is safe because the atomic types work with interior mutability. All modifications of an atomic change the value through a shared reference, and can do so safely as long as they use atomic operations. Any use of the returned raw pointer requires an `unsafe` block and still has to uphold the same restriction: operations on it must be atomic.

# Examples

ⓘ

    use std::sync::atomic::AtomicI32;

    extern "C" {
        fn my_atomic_op(arg: *mut i32);
    }

    let mut atomic = AtomicI32::new(1);

    unsafe {
        my_atomic_op(atomic.as_mut_ptr());
    }

Run

## Trait Implementations

### `impl Debug for AtomicI32`[src]

#### `fn fmt(&self, f: &mut Formatter<'_>) -> Result`[src]

Formats the value using the given formatter. Read more

### `impl Default for AtomicI32`[src]

#### `fn default() -> Self`[src]

Returns the "default value" for a type. Read more

### `impl From<i32> for AtomicI32`[src]

#### `fn from(v: i32) -> Self`[src]

Converts an `i32` into an `AtomicI32`.

### `impl Sync for AtomicI32`[src]

## Auto Trait Implementations

### `impl Send for AtomicI32`[src]

### `impl Unpin for AtomicI32`[src]

## Blanket Implementations

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `pub fn type_id(&Self) -> TypeId`[src]

Gets the `TypeId` of `self`. Read more

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow(&Self) -> &T`[src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow_mut(&mut Self) -> &mut T`[src]

Mutably borrows from an owned value. Read more

### `impl<T> From<T> for T`[src]

#### `pub fn from(T) -> T`[src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `pub fn into(Self) -> U`[src]

Performs the conversion.

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `pub fn try_from(U) -> Result<T, <T as TryFrom<U>>::Error>`[src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `pub fn try_into(Self) -> Result<U, <U as TryFrom<T>>::Error>`[src]

Performs the conversion.