Struct WaitGroup

pub struct WaitGroup { /* private fields */ }

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();

Implementations

impl WaitGroup

pub fn new() -> Self

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)

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 Clone for WaitGroup

fn clone(&self) -> WaitGroup

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for WaitGroup

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

Formats the value using the given formatter.

impl Default for WaitGroup

fn default() -> Self

Returns the “default value” for a type.

impl Drop for WaitGroup

fn drop(&mut self)

Executes the destructor for this type.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 8 bytes