ch3-07-release-acquire-unsafe.rs

use std::sync::atomic::AtomicBool;
use std::sync::atomic::Ordering::{Acquire, Release};
use std::thread;
use std::time::Duration;

static mut DATA: u64 = 0;
static READY: AtomicBool = AtomicBool::new(false);

fn main() {
    thread::spawn(|| {
        // Safety: Nothing else is accessing DATA,
        // because we haven't set the READY flag yet.
        unsafe { DATA = 123 };
        READY.store(true, Release); // Everything from before this store ..
    });
    while !READY.load(Acquire) { // .. is visible after this loads `true`.
        thread::sleep(Duration::from_millis(100));
        println!("waiting...");
    }
    // Safety: Nothing is mutating DATA, because READY is set.
    println!("{}", unsafe { DATA });
}