Attribute Macro tokio::main

#[main]

Marks async function to be executed by selected runtime. This macro helps set up a Runtime without requiring the user to use Runtime or Builder directly.

Function arguments:

Arguments are allowed for any functions aside from main which is special

Usage

Using default

#[tokio::main(flavor = "current_thread")]
async fn main() {
    println!("Hello world");
}

Equivalent code not using #[tokio::main]

fn main() {
    tokio::runtime::Builder::new_current_thread()
        .enable_all()
        .build()
        .unwrap()
        .block_on(async {
            println!("Hello world");
        })
}

Rename package

use tokio as tokio1;

#[tokio1::main(crate = "tokio1")]
async fn main() {
    println!("Hello world");
}

Equivalent code not using #[tokio::main]

use tokio as tokio1;

fn main() {
    tokio1::runtime::Builder::new_multi_thread()
        .enable_all()
        .build()
        .unwrap()
        .block_on(async {
            println!("Hello world");
        })
}