Trait std::error::Error1.0.0 [] [src]

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

    fn cause(&self) -> Option<&Error> { ... }
}

Base functionality for all errors in Rust.

Required Methods

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"),
}Run

Provided Methods

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"),
    }
}Run

Methods

impl Error + 'static
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1.3.0
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Returns true if the boxed type is the same as T

1.3.0
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Returns some reference to the boxed value if it is of type T, or None if it isn't.

1.3.0
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Returns some mutable reference to the boxed value if it is of type T, or None if it isn't.

impl Error + Send + 'static
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1.3.0
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Forwards to the method defined on the type Any.

1.3.0
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Forwards to the method defined on the type Any.

1.3.0
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Forwards to the method defined on the type Any.

impl Error + Send + Sync + 'static
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1.3.0
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Forwards to the method defined on the type Any.

1.3.0
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Forwards to the method defined on the type Any.

1.3.0
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Forwards to the method defined on the type Any.

impl Error
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1.3.0
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Attempt to downcast the box to a concrete type.

impl Error + Send
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1.3.0
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Attempt to downcast the box to a concrete type.

impl Error + Send + Sync
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1.3.0
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Attempt to downcast the box to a concrete type.

Implementations on Foreign Types

impl Error for TryFromSliceError
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1.0.0
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Implementors