Rc shared ownership in Rust

Reference counting for multiple owners of one value.

use std::rc::Rc;

fn main() {
    let shared = Rc::new(vec![1, 2, 3]);
    let a = Rc::clone(&shared);
    let b = Rc::clone(&shared);

    let count = Rc::strong_count(&shared);
    let total: i32 = a.iter().sum();
    println!("{count} {total} {}", b.len());
}

How it works

1. Rc::new wraps a value for sharing.
2. Rc::clone bumps the count, not the data.
3. strong_count reports how many owners exist.

Keywords and builtins used here

• fn
• i32
• let
• main
• use

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Type this snippet

Step 2 of 2 in Smart pointers, step 14 of 15 in Ownership & borrowing.

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