Generate sequential IDs for each instance of a struct

Question

I\'m writing a system where I have a collection of Objects, and each Object has a unique integral ID. Here\'s how I would do it in C++:

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Answer 1

Atomic variables can live in statics, so you can use it relatively straightforwardly (the downside is that you have global state).

Example code: (playground link)

use std::{
    sync::atomic::{AtomicUsize, Ordering},
    thread,
};

static OBJECT_COUNTER: AtomicUsize = AtomicUsize::new(0);

#[derive(Debug)]
struct Object(usize);

impl Object {
    fn new() -> Self {
        Object(OBJECT_COUNTER.fetch_add(1, Ordering::SeqCst))
    }
}

fn main() {
    let threads = (0..10)
        .map(|_| thread::spawn(|| Object::new()))
        .collect::>();

    for t in threads {
        println!("{:?}", t.join().unwrap());
    }
}