Struct serde::lib::core::sync::OnceState

1.51.0 · source · []
pub struct OnceState {
    poisoned: bool,
    set_state_on_drop_to: Cell<*mut ()>,
}
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

poisoned: boolset_state_on_drop_to: Cell<*mut ()>

Implementations

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

Formats the value using the given formatter. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

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

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.