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umanwizard • yesterday at 11:19 PM • 1 reply • view on HN

> I pretty new to Rust and I’m wondering why global mutables are hard?

They're not.

  fn main() {
      unsafe {
          COUNTER += 1;
          println!("COUNTER = {}", COUNTER);
      }
  
      unsafe {
          COUNTER += 10;
          println!("COUNTER = {}", COUNTER);
      }
  }
Global mutable variables are as easy in Rust as in any other language. Unlike other languages, Rust also provides better things that you can use instead.

Replies

raggi • today at 12:49 AM

People always complain about unsafe, so I prefer to just show the safe version.

  use std::sync::Mutex;

  static LIST: Mutex<Vec<String>> = Mutex::new(Vec::new());

  fn main() -> Result<(), Box<dyn std::error::Error>> {

      LIST.lock()?.push("hello world".to_string());
      println!("{}", LIST.lock()?[0]);

      Ok(())
  }