Struct WaitGroup 

pub struct WaitGroup { /* private fields */ }

A synchronisation barrier: wait for a set of goroutines to complete.

The typical usage pattern is:

use std::sync::Arc;
use go_lib::sync::WaitGroup;

let wg = Arc::new(WaitGroup::new());
for i in 0..5 {
    let wg = Arc::clone(&wg);
    go_lib::run(move || {
        wg.add(1);
        // ... spawn goroutine that calls wg.done() when finished ...
    });
}
// wg.wait();  // blocks until all Done() calls have been made

Implementations

impl WaitGroup

pub fn new() -> Self

Create a new WaitGroup with a counter of zero.

pub fn add(&self, delta: i64)

Add delta to the counter.

delta is typically positive when called before spawning goroutines and negative when they finish (see done).

Panics

Panics if the counter drops below zero.

pub fn done(&self)

Decrement the counter by one.

Shorthand for self.add(-1).

pub fn wait(&self)

Block until the counter is zero.

When called from a goroutine: suspends the goroutine back into the scheduler via gopark so the M and P remain free to run other goroutines. Resumed by add calling goready when the counter reaches zero.

When called from a bare OS thread (outside the go-lib scheduler): blocks the thread on an internal Condvar.

Trait Implementations

impl Default for WaitGroup

fn default() -> Self

Returns the “default value” for a type.