3 ms·
> I pretty new to Rust and I’m wondering why global mutables are hard? They're not. fn main() { unsafe { COUNTER += 1; println!("C
by School-Cotton 11mo ago
> 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.
- raggi 11mo agoPeople 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(()) }
- hu3 11mo agoThis is completely different from the previous example. It doesn't increment anything for starters. The example would be more convoluted if it did the same thing. And strings in rust always delivers the WTFs I need o na Friday: "hello world".to_string()
- raggi 11mo agouse std::sync::Mutex; fn main() -> Result<(), Box<dyn std::error::Error>> { static PEDANTRY: Mutex<u64> = Mutex::new(0); *PEDANTRY.lock()? += 1; println!("{}", PEDANTRY.lock()?); Ok(()) }
- hu3 11mo agoStill different. Yours only increments once. Doesn't pass basic QA. And declaring a static variable inside a function, even if in main, smells.
- raggi 11mo agoOP you keep comparing to doesn't even declare the variable. I'm done with you.
- School-Cotton 11mo agoOP here, not showing how to declare the variable was an oversight on my part. static mut COUNTER: u32 = 0; (at top-level) If on 2024 edition, you will additionally need #![allow(static_mut_refs)]
- raggi 11mo agoYup, your example was fine, as I said I just wanted to show a safe method too :-)