Rust Programming Cookbook

How to do it...

Let's create an error wrapper in a few steps:

1. Open the project you created with cargo new multiple-errors with VS Code.
2. Open src/main.rs to and add some imports at the top:

use std::fmt;use std::io;use std::error::Error;

3. In our application, we will deal with three user-defined errors. Let's declare them right after the imports:

#[derive(Debug)]pub struct InvalidDeviceIdError(usize);#[derive(Debug)]pub struct DeviceNotPresentError(usize);#[derive(Debug)]pub struct UnexpectedDeviceStateError {}

4. Now for the wrapper: since we are dealing with multiple variations of something, enum will fit the purpose perfectly:

#[derive(Debug)]pub enum ErrorWrapper {    Io(io::Error),    Db(InvalidDeviceIdError), Device(DeviceNotPresentError), ...