Struct WaitQueue 

pub struct WaitQueue { /* private fields */ }

A FIFO queue of tasks waiting for an event.

See the module documentation for usage notes and the lost-wakeup guarantee.

Implementations

impl WaitQueue

pub const fn new() -> Self

Create a new empty wait queue.

pub fn wait(&self)

Block the calling task until explicitly woken.

Prefer wait_until when you have a condition to test, to avoid spurious-wakeup loops and to benefit from the compile-time condition guarantee.

Panics

Panics if called outside of a task context (no current task).

pub fn wait_until<F, T>(&self, condition: F) -> T

where F: FnMut() -> Option<T>,

Block the calling task until condition() returns Some(T).

The condition is checked under the waiters lock, then the task is inserted into the queue (still under the lock) before blocking. This makes the check-then-block sequence atomic with respect to concurrent wake_one() / wake_all() calls.

The task is re-woken for every notification and re-evaluates the condition; spurious wakeups are impossible because the condition is always re-checked before the next sleep.

Panics

Panics if called outside of a task context (no current task).

pub fn wake_one(&self) -> bool

Wake the first waiting task (FIFO order).

Returns true if a task was successfully woken, false if the queue was empty.

pub fn wake_all(&self) -> usize

Wake all waiting tasks.

Returns the number of tasks that were woken.

pub fn waiter_count(&self) -> usize

Returns the number of tasks currently registered in this queue.