Learn Rust Coding · Lesson

pub and Visibility

Control access.

Private by Default

In Rust, everything inside a module is private by default. Other modules cannot see it unless you opt in with pub.

This safe default keeps implementation details hidden until you deliberately expose them.

Marking a function pub makes it callable from outside its module. Without it, the call fails to compile.

mod math {
    pub fn square(x: i32) -> i32 {
        x * x
    }
}

fn main() {
    println!("{}", math::square(5));
}