open file error handling

---

examples/files/open-file-handling/src/main.rs

fn main() {
    //let res = this_or_that();
    //println!("{:?}", res);
}

fn this_or_that() -> Option


//
//
//use std::fs::File;
//use std::io;
//
//
//fn main() -> Result<String, io::Error> {
//    let filename = "README.md";
//    //let res = File::open(filename); // return Ok() and the Filehandle inside it
//    //println!("{:?}", res);
//
//    //let res = File::open(filename).unwrap(); // returns the Filehandle
//    //println!("{:?}", res);
//
//    let res = File::open(filename)?; // the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
//    println!("{:?}", res);
//    Ok(("ok"))
//}