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.