# [−][src]Struct crossbeam_utils::sync::Parker

    pub struct Parker { /* fields omitted */ }

A thread parking primitive.

Conceptually, each `Parker` has an associated token which is initially not present:

- The `park` method blocks the current thread unless or until the token is available, at which point it automatically consumes the token. It may also return spuriously, without consuming the token.

- The `park_timeout` method works the same as `park`, but blocks for a specified maximum time.

- The `unpark` method atomically makes the token available if it wasn't already. Because the token is initially absent, `unpark` followed by `park` will result in the second call returning immediately.

In other words, each `Parker` acts a bit like a spinlock that can be locked and unlocked using `park` and `unpark`.

# Examples

    use std::thread;
    use std::time::Duration;
    use crossbeam_utils::sync::Parker;

    let mut p = Parker::new();
    let u = p.unparker().clone();

    // Make the token available.
    u.unpark();
    // Wakes up immediately and consumes the token.
    p.park();

    thread::spawn(move || {
        thread::sleep(Duration::from_millis(500));
        u.unpark();
    });

    // Wakes up when `u.unpark()` provides the token, but may also wake up
    // spuriously before that without consuming the token.
    p.park();

## Methods

### `impl Parker`[src]

#### `pub fn new() -> Parker`[src]

Creates a new `Parker`.

# Examples

    use crossbeam_utils::sync::Parker;

    let p = Parker::new();

#### `pub fn park(&self)`[src]

Blocks the current thread until the token is made available.

A call to `park` may wake up spuriously without consuming the token, and callers should be prepared for this possibility.

# Examples

    use crossbeam_utils::sync::Parker;

    let mut p = Parker::new();
    let u = p.unparker().clone();

    // Make the token available.
    u.unpark();

    // Wakes up immediately and consumes the token.
    p.park();

#### `pub fn park_timeout(&self, timeout: Duration)`[src]

Blocks the current thread until the token is made available, but only for a limited time.

A call to `park_timeout` may wake up spuriously without consuming the token, and callers should be prepared for this possibility.

# Examples

    use std::time::Duration;
    use crossbeam_utils::sync::Parker;

    let mut p = Parker::new();

    // Waits for the token to become available, but will not wait longer than 500 ms.
    p.park_timeout(Duration::from_millis(500));

#### `pub fn unparker(&self) -> &Unparker`[src]

Returns a reference to an associated `Unparker`.

The returned `Unparker` doesn't have to be used by reference - it can also be cloned.

# Examples

    use crossbeam_utils::sync::Parker;

    let mut p = Parker::new();
    let u = p.unparker().clone();

    // Make the token available.
    u.unpark();
    // Wakes up immediately and consumes the token.
    p.park();

## Trait Implementations

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

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

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

Formats the value using the given formatter. Read more

## Auto Trait Implementations

### `impl Unpin for Parker`

### `impl !Sync for Parker`

### `impl !UnwindSafe for Parker`

### `impl !RefUnwindSafe for Parker`

## Blanket Implementations

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

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

Performs the conversion.

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

#### `fn from(t: T) -> T`[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.

#### `fn try_from(value: 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.

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

Performs the conversion.

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

####
ⓘImportant traits for &'_ mut W

### Important traits for &'_ mut W

`impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;`
`fn borrow_mut(&mut self) -> &mut T`[src]

Mutably borrows from an owned value. Read more

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

####
ⓘImportant traits for &'_ mut W

### Important traits for &'_ mut W

`impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Unpin + Future + ?Sized, type Output = <F as Future>::Output;`
`fn borrow(&self) -> &T`[src]

Immutably borrows from an owned value. Read more

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

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

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

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