Struct `OnceState`

pub struct OnceState { pub(crate) inner: OnceState }

State yielded to [Once::call_once_force()]’s closure parameter. The state can be used to query the poison status of the Once.

Fields

inner: OnceState

Implementations

`impl OnceState`

fn is_poisoned(&self) -> bool

Returns true if the associated Once was poisoned prior to the invocation of the closure passed to [Once::call_once_force()].

Examples

A poisoned [Once]:

use std::sync::Once;
use std::thread;

static INIT: Once = Once::new();

// poison the once
let handle = thread::spawn(|| {
    INIT.call_once(|| panic!());
});
assert!(handle.join().is_err());

INIT.call_once_force(|state| {
    assert!(state.is_poisoned());
});

An unpoisoned [Once]:

use std::sync::Once;

static INIT: Once = Once::new();

INIT.call_once_force(|state| {
    assert!(!state.is_poisoned());
});

fn poison(&self)

Poison the associated Once without explicitly panicking.

Trait Implementations

`impl Debug for OnceState`

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

Auto Trait Implementations

`impl !Freeze for OnceState`

`impl !RefUnwindSafe for OnceState`

`impl !Sync for OnceState`

`impl Send for OnceState`

`impl Unpin for OnceState`

`impl UnsafeUnpin for OnceState`

`impl UnwindSafe for OnceState`

Blanket Implementations

`impl<T> Any for OnceState where T: 'static + ?Sized,`

fn type_id(&self) -> TypeId

`impl<T> Borrow<T> for OnceState where T: ?Sized,`

fn borrow(&self) -> &T

`impl<T> BorrowMut<T> for OnceState where T: ?Sized,`

fn borrow_mut(&mut self) -> &mut T

`impl<T> From<T> for OnceState`

fn from(t: T) -> T: Returns the argument unchanged.

`impl<T> SizeHint for OnceState where T: ?Sized,`

fn lower_bound(&self) -> usize
fn upper_bound(&self) -> Option<usize>

`impl<T> SizedTypeProperties for OnceState`

`impl<T, U> Into for OnceState where U: From<T>,`

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of [From]<T> for U chooses to do.

`impl<T, U> TryFrom for OnceState where U: Into<T>,`

type Error = Infallible;
fn try_from(value: U) -> Result<T, <T as TryFrom>::Error>

`impl<T, U> TryInto for OnceState where U: TryFrom<T>,`

type Error = >::Error;
fn try_into(self) -> Result<U, >::Error>