Arc example rarely executes all threads

[c-antin]

Running the example of Arc results in a variing number of prints.

Is this a bug in rust or is thread::spawn not used correctly/up-to-date? Sometimes there are even incomplete prints:

[c-antin]

Oh, I know the reason now! The main thread ends before all threads are run.
See https://doc.rust-lang.org/book/ch16-01-threads.html

[c-antin]

This way all threads are waited for:

use std::sync::Arc;
use std::thread;

fn main() {
    // This variable declaration is where its value is specified.
    let apple = Arc::new("the same apple");

    let mut threads = vec![];

    for _ in 0..10 {
        // Here there is no value specification as it is a pointer to a reference
        // in the memory heap.
        let apple = Arc::clone(&apple);

        threads.push(thread::spawn(move || {
            // As Arc was used, threads can be spawned using the value allocated
            // in the Arc variable pointer's location.
            println!("{:?}", apple);
        }));
    }

    for handle in threads {
        handle.join().unwrap();
    }
}

[Rqnsom]

Hi c-antin,

I've updated this just recently, but without using join function, but with sleep instead:

Joining threads could be used, but that concept is later introduced in 20.1. Threads, so I prefer simple sleep here.

See my PR for more:
#1552 (comment)

[Rqnsom]

Should we then close this issue?

[marioidival]

Yes! Thanks for that @Rqnsom and @c-antin