pub struct OnceState {
pub(crate) inner: OnceState,
}
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
.
Fields§
§inner: OnceState
Implementations§
source§impl OnceState
impl OnceState
1.51.0 · 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());
});
An unpoisoned Once
:
use std::sync::Once;
static INIT: Once = Once::new();
INIT.call_once_force(|state| {
assert!(!state.is_poisoned());
});
Trait Implementations§
Auto Trait Implementations§
impl !Freeze for OnceState
impl !RefUnwindSafe for OnceState
impl Send for OnceState
impl !Sync for OnceState
impl Unpin for OnceState
impl UnwindSafe for OnceState
Blanket Implementations§
§impl<T> ArchivePointee for T
impl<T> ArchivePointee for T
§type ArchivedMetadata = ()
type ArchivedMetadata = ()
The archived version of the pointer metadata for this type.
§fn pointer_metadata(
_: &<T as ArchivePointee>::ArchivedMetadata,
) -> <T as Pointee>::Metadata
fn pointer_metadata( _: &<T as ArchivePointee>::ArchivedMetadata, ) -> <T as Pointee>::Metadata
Converts some archived metadata to the pointer metadata for itself.
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
§impl<T> LayoutRaw for T
impl<T> LayoutRaw for T
§fn layout_raw(_: <T as Pointee>::Metadata) -> Result<Layout, LayoutError>
fn layout_raw(_: <T as Pointee>::Metadata) -> Result<Layout, LayoutError>
Returns the layout of the type.