Module std::error [−] [src]

Traits for working with Errors.

The Error trait

Error is a trait representing the basic expectations for error values, i.e. values of type E in Result<T, E>. At a minimum, errors must provide a description, but they may optionally provide additional detail (via Display) and cause chain information:

fn main() { use std::fmt::Display; trait Error: Display { fn description(&self) -> &str; fn cause(&self) -> Option<&Error> { None } } }
use std::fmt::Display;

trait Error: Display {
    fn description(&self) -> &str;

    fn cause(&self) -> Option<&Error> { None }
}

The cause method is generally used when errors cross "abstraction boundaries", i.e. when a one module must report an error that is "caused" by an error from a lower-level module. This setup makes it possible for the high-level module to provide its own errors that do not commit to any particular implementation, but also reveal some of its implementation for debugging via cause chains.

Traits

Error

Base functionality for all errors in Rust.