pub struct OnceState { /* private fields */ }Expand description
State yielded to Once::call_once_force()’s closure parameter. The state
can be used to query the poison status of the Once.
Implementations§
source§impl OnceState
impl OnceState
sourcepub fn is_poisoned(&self) -> bool
pub 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());
});RunAn unpoisoned Once:
use std::sync::Once;
static INIT: Once = Once::new();
INIT.call_once_force(|state| {
assert!(!state.is_poisoned());
});RunTrait Implementations§
Auto Trait Implementations§
impl !RefUnwindSafe for OnceState
impl Send for OnceState
impl !Sync for OnceState
impl Unpin for OnceState
impl UnwindSafe for OnceState
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more