Struct Barrier

pub struct Barrier { /* private fields */ }

Available on unstable only.

A barrier enables multiple tasks to synchronize the beginning of some computation.

Examples

use async_std::sync::{Arc, Barrier};
use async_std::task;

let mut handles = Vec::with_capacity(10);
let barrier = Arc::new(Barrier::new(10));
for _ in 0..10 {
    let c = barrier.clone();
    // The same messages will be printed together.
    // You will NOT see any interleaving.
    handles.push(task::spawn(async move {
        println!("before wait");
        c.wait().await;
        println!("after wait");
    }));
}
// Wait for the other futures to finish.
for handle in handles {
    handle.await;
}

Implementations

impl Barrier

pub fn new(n: usize) -> Barrier

Creates a new barrier that can block a given number of tasks.

A barrier will block n-1 tasks which call wait and then wake up all tasks at once when the nth task calls wait.

Examples

use std::sync::Barrier;

let barrier = Barrier::new(10);

pub async fn wait(&self) -> BarrierWaitResult

Blocks the current task until all tasks have rendezvoused here.

Barriers are re-usable after all tasks have rendezvoused once, and can be used continuously.

A single (arbitrary) task will receive a BarrierWaitResult that returns true from is_leader when returning from this function, and all other tasks will receive a result that will return false from is_leader.

Examples

use async_std::sync::{Arc, Barrier};
use async_std::task;

let mut handles = Vec::with_capacity(10);
let barrier = Arc::new(Barrier::new(10));
for _ in 0..10 {
    let c = barrier.clone();
    // The same messages will be printed together.
    // You will NOT see any interleaving.
    handles.push(task::spawn(async move {
        println!("before wait");
        c.wait().await;
        println!("after wait");
    }));
}
// Wait for the other futures to finish.
for handle in handles {
    handle.await;
}

Trait Implementations

impl Debug for Barrier

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

Formats the value using the given formatter.