Struct tokio::task::JoinError

pub struct JoinError { /* fields omitted */ }

Task failed to execute to completion.

Implementations

impl JoinError

pub fn is_cancelled(&self) -> bool

Returns true if the error was caused by the task being cancelled

pub fn is_panic(&self) -> bool

Returns true if the error was caused by the task panicking

Examples

use std::panic;

#[tokio::main]
async fn main() {
    let err = tokio::spawn(async {
        panic!("boom");
    }).await.unwrap_err();

    assert!(err.is_panic());
}

pub fn into_panic(self) -> Box<dyn Any + Send + 'static>

Consumes the join error, returning the object with which the task panicked.

Panics

into_panic() panics if the Error does not represent the underlying task terminating with a panic. Use is_panic to check the error reason or try_into_panic for a variant that does not panic.

Examples

use std::panic;

#[tokio::main]
async fn main() {
    let err = tokio::spawn(async {
        panic!("boom");
    }).await.unwrap_err();

    if err.is_panic() {
        // Resume the panic on the main task
        panic::resume_unwind(err.into_panic());
    }
}

pub fn try_into_panic(self) -> Result<Box<dyn Any + Send + 'static>, JoinError>

Consumes the join error, returning the object with which the task panicked if the task terminated due to a panic. Otherwise, self is returned.

Examples

use std::panic;

#[tokio::main]
async fn main() {
    let err = tokio::spawn(async {
        panic!("boom");
    }).await.unwrap_err();

    if let Ok(reason) = err.try_into_panic() {
        // Resume the panic on the main task
        panic::resume_unwind(reason);
    }
}

Trait Implementations

impl Debug for JoinError

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for JoinError

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for JoinError

fn source(&self) -> Option<&(dyn Error + 'static)>

The lower-level source of this error, if any.

fn backtrace(&self) -> Option<&Backtrace>

🔬 This is a nightly-only experimental API. (backtrace)

Returns a stack backtrace, if available, of where this error occurred.

fn description(&self) -> &str

👎 Deprecated since 1.42.0:

use the Display impl or to_string()

if let Err(e) = "xc".parse::<u32>() { // Print e itself, no need for description(). eprintln!("Error: {}", e); }

fn cause(&self) -> Option<&dyn Error>

👎 Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

impl From<JoinError> for Error

fn from(src: JoinError) -> Error

Performs the conversion.