Struct std::sync::PoisonError

[+] Show declaration

pub struct PoisonError<T> { /* fields omitted */ }

[−] Expand description

A type of error which can be returned whenever a lock is acquired.

Both Mutexes and RwLocks are poisoned whenever a thread fails while the lock is held. The precise semantics for when a lock is poisoned is documented on each lock, but once a lock is poisoned then all future acquisitions will return this error.

Examples

use std::sync::{Arc, Mutex};
use std::thread;

let mutex = Arc::new(Mutex::new(1));

// poison the mutex
let c_mutex = mutex.clone();
let _ = thread::spawn(move || {
    let mut data = c_mutex.lock().unwrap();
    *data = 2;
    panic!();
}).join();

match mutex.lock() {
    Ok(_) => unreachable!(),
    Err(p_err) => {
        let data = p_err.get_ref();
        println!("recovered: {}", data);
    }
};

Methods

impl<T> PoisonError<T>

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pub fn new(guard: T) -> PoisonError<T>

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Creates a PoisonError.

This is generally created by methods like Mutex::lock or RwLock::read.

pub fn into_inner(self) -> T

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Consumes this error indicating that a lock is poisoned, returning the underlying guard to allow access regardless.

Examples

use std::collections::HashSet;
use std::sync::{Arc, Mutex};
use std::thread;

let mutex = Arc::new(Mutex::new(HashSet::new()));

// poison the mutex
let c_mutex = mutex.clone();
let _ = thread::spawn(move || {
    let mut data = c_mutex.lock().unwrap();
    data.insert(10);
    panic!();
}).join();

let p_err = mutex.lock().unwrap_err();
let data = p_err.into_inner();
println!("recovered {} items", data.len());

Important traits for &'a mut I

impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;impl<'a, R: Read + ?Sized> Read for &'a mut Rimpl<'a, W: Write + ?Sized> Write for &'a mut W

pub fn get_ref(&self) -> &T

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Reaches into this error indicating that a lock is poisoned, returning a reference to the underlying guard to allow access regardless.

Important traits for &'a mut I

impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;impl<'a, R: Read + ?Sized> Read for &'a mut Rimpl<'a, W: Write + ?Sized> Write for &'a mut W

pub fn get_mut(&mut self) -> &mut T

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Reaches into this error indicating that a lock is poisoned, returning a mutable reference to the underlying guard to allow access regardless.

Trait Implementations

impl<T> Error for PoisonError<T>

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fn description(&self) -> &str

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This method is soft-deprecated.

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

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Deprecating in 1.33.0

: replaced by Error::source, which can support downcasting

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

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

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

impl<T> Display for PoisonError<T>

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fn fmt(&self, f: &mut Formatter) -> Result

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Formats the value using the given formatter.

impl<T> Debug for PoisonError<T>

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fn fmt(&self, f: &mut Formatter) -> Result

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Formats the value using the given formatter.

impl<T> From<PoisonError<T>> for TryLockError<T>

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fn from(err: PoisonError<T>) -> TryLockError<T>

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Performs the conversion.