Trait error::Error
[−]
[src]
pub trait Error: Debug + Display { fn description(&self) -> &str; fn cause(&self) -> Option<&Error> { ... } }
Required Methods
fn description(&self) -> &str
A short description of the error.
The description should only be used for a simple message.
It should not contain newlines or sentence-ending punctuation,
to facilitate embedding in larger user-facing strings.
For showing formatted error messages with more information see
Display
.
Examples
use std::error::Error; match "xc".parse::<u32>() { Err(e) => { println!("Error: {}", e.description()); } _ => println!("No error"), }
Provided Methods
fn cause(&self) -> Option<&Error>
The lower-level cause of this error, if any.
Examples
use std::error::Error; use std::fmt; #[derive(Debug)] struct SuperError { side: SuperErrorSideKick, } impl fmt::Display for SuperError { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "SuperError is here!") } } impl Error for SuperError { fn description(&self) -> &str { "I'm the superhero of errors" } fn cause(&self) -> Option<&Error> { Some(&self.side) } } #[derive(Debug)] struct SuperErrorSideKick; impl fmt::Display for SuperErrorSideKick { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "SuperErrorSideKick is here!") } } impl Error for SuperErrorSideKick { fn description(&self) -> &str { "I'm SuperError side kick" } } fn get_super_error() -> Result<(), SuperError> { Err(SuperError { side: SuperErrorSideKick }) } fn main() { match get_super_error() { Err(e) => { println!("Error: {}", e.description()); println!("Caused by: {}", e.cause().unwrap()); } _ => println!("No error"), } }