CODEWITHSUNDEEP
rust
mnk802
mnk802

Reputation: 115

Rust Error When Passing Reference to TCPListener

use std::net::{TcpListener, TcpStream};

pub struct Server {
    addr: String,
}

impl Server{
    pub fn new(addr: String) -> Self {
        Self {
            addr: addr
        }
    }

    pub fn run(&self) { // can make this (self) since we can give ownership of addr to run function.
        println!("Listening on: {}", self.addr);
        
        let listener = TcpListener::bind(self.addr);
    }

}

I am new to rust so please forgive the ignorance. I am trying to pass a reference of self.addr to the TcpListener but it is throwing this error:

cannot move out of `self.addr` which is behind a shared reference
move occurs because `self.addr` has type `String`, which does not implement the `Copy` trait

When I change it to

let listener = TcpListener::bind(&self.addr);

it works. I thought that &self was already a reference to the variable self.addr which I am trying to use. So why do I need to reference it again for the TcpListener?

Upvotes: 1

Views: 185

Answers (1)

Chayim Friedman
Chayim Friedman

Reputation: 71005

self is a reference. self.addr is not.

When you access self.addr, you dereference self. self.addr has type String, not &String. If you want a reference (or to not move it), you need to take a reference explicitly.

Upvotes: 1

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