# [−][src]Struct crossbeam::sync::WaitGroup

    pub struct WaitGroup { /* fields omitted */ }

Enables threads to synchronize the beginning or end of some computation.

# Wait groups vs barriers

`WaitGroup` is very similar to `Barrier`, but there are a few differences:

- `Barrier` needs to know the number of threads at construction, while `WaitGroup` is cloned to register more threads.

- A `Barrier` can be reused even after all threads have synchronized, while a `WaitGroup` synchronizes threads only once.

- All threads wait for others to reach the `Barrier`. With `WaitGroup`, each thread can choose to either wait for other threads or to continue without blocking.

# Examples

    use crossbeam_utils::sync::WaitGroup;
    use std::thread;

    // Create a new wait group.
    let wg = WaitGroup::new();

    for _ in 0..4 {
        // Create another reference to the wait group.
        let wg = wg.clone();

        thread::spawn(move || {
            // Do some work.

            // Drop the reference to the wait group.
            drop(wg);
        });
    }

    // Block until all threads have finished their work.
    wg.wait();

## Methods

### `impl WaitGroup`[src]

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

Creates a new wait group and returns the single reference to it.

# Examples

    use crossbeam_utils::sync::WaitGroup;

    let wg = WaitGroup::new();

#### `pub fn wait(self)`[src]

Drops this reference and waits until all other references are dropped.

# Examples

    use crossbeam_utils::sync::WaitGroup;
    use std::thread;

    let wg = WaitGroup::new();

    thread::spawn({
        let wg = wg.clone();
        move || {
            // Block until both threads have reached `wait()`.
            wg.wait();
        }
    });

    // Block until both threads have reached `wait()`.
    wg.wait();

## Trait Implementations

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

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

Formats the value using the given formatter. Read more

### `impl Clone for WaitGroup`[src]

#### `fn clone(&self) -> WaitGroup`[src]

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`1.0.0[src]

Performs copy-assignment from `source`. Read more

### `impl Drop for WaitGroup`[src]

#### `fn drop(&mut self)`[src]

Executes the destructor for this type. Read more

## Auto Trait Implementations

### `impl Send for WaitGroup`

### `impl Unpin for WaitGroup`

### `impl Sync for WaitGroup`

### `impl !UnwindSafe for WaitGroup`

### `impl !RefUnwindSafe for WaitGroup`

## Blanket Implementations

### `impl<T> ToOwned for T where
T: Clone,` [src]

#### `type Owned = T`

The resulting type after obtaining ownership.

#### `fn to_owned(&self) -> T`[src]

Creates owned data from borrowed data, usually by cloning. Read more

#### `fn clone_into(&self, target: &mut T)`[src]

🔬 This is a nightly-only experimental API. (`toowned_clone_into`)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

### `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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