code_learner46 · 09.05.2026

Can you use global variables in Rust? How to declare global state?

Hello! I've been writing in Rust for a couple of weeks and ran into a problem. I need to store application configuration and a request counter accessible from different modules. In C++ I would do it like this: ```rust // My attempt (doesn't compile) static COUNTER: i32 = 0; static CONFIG: HashMap = HashMap::new(); fn increment() { COUNTER += 1; // Error: cannot assign to immutable static } fn main() { CONFIG.insert("host".to_string(), "localhost".to_string()); // Error println!("{}", COUNTER); } ``` The compiler complains about mutability and about `HashMap` it says something about `const fn` and allocations. I read that global variables in Rust are complicated, but how do you do shared settings then? I need: 1. A simple counter that can be incremented from different threads. 2. A co

0 responses

No answers yet.