error-handling - 有没有办法从std::io::Error获取OS错误代码？

Question

当我运行以下命令时:

use std::fs::File;

fn main() {
    let filename = "not_exists.txt";
    let reader = File::open(filename);

    match reader {
        Ok(_) => println!(" * file '{}' opened successfully.", filename),
        Err(e) => {
            println!("{:?}", &e);
        }
    }
}

输出为:

Os { code: 2, kind: NotFound, message: "No such file or directory" }

是否可以将该代码作为整数获取？

Answer 1

使用 io::Error::raw_os_error :

match reader {
    Ok(_) => println!(" * file '{}' opened successfully.", filename),
    Err(e) => println!("{:?}", e.raw_os_error()),
}

输出:

Some(2)

也可以看看:

How does one get the error message as provided by the system without the "os error n" suffix?