Struct tokio_util::loom::sync::Barrier

pub struct Barrier {
    lock: Mutex<BarrierState>,
    cvar: Condvar,
    num_threads: usize,
}

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

Examples

use std::sync::{Arc, Barrier};
use std::thread;

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

Fields

lock: Mutex<BarrierState>

cvar: Condvar

num_threads: usize

Implementations

impl Barrier

pub const fn new(n: usize) -> Barrier

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

A barrier will block n-1 threads which call wait() and then wake up all threads at once when the nth thread calls wait().

Examples

use std::sync::Barrier;

let barrier = Barrier::new(10);

pub fn wait(&self) -> BarrierWaitResult

Blocks the current thread until all threads have rendezvoused here.

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

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

Examples

use std::sync::{Arc, Barrier};
use std::thread;

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

Trait Implementations

impl Debug for Barrier

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

Formats the value using the given formatter.