# Error code E0752

The entry point of the program was marked as `async`.

Erroneous code example:

    async fn main() -> Result<(), ()> { // error!
        Ok(())
    }

`fn main()` or the specified start function is not allowed to be `async`. Not having a correct async runtime library setup may cause this error. To fix it, declare the entry point without `async`:

    fn main() -> Result<(), ()> { // ok!
        Ok(())
    }