Struct axtask::WaitQueue

pub struct WaitQueue { /* private fields */ }

Available on crate feature multitask only.

A queue to store sleeping tasks.

Examples

use axtask::WaitQueue;
use core::sync::atomic::{AtomicU32, Ordering};

static VALUE: AtomicU32 = AtomicU32::new(0);
static WQ: WaitQueue = WaitQueue::new();

axtask::init_scheduler();
// spawn a new task that updates `VALUE` and notifies the main task
axtask::spawn(|| {
    assert_eq!(VALUE.load(Ordering::Relaxed), 0);
    VALUE.fetch_add(1, Ordering::Relaxed);
    WQ.notify_one(true); // wake up the main task
});

WQ.wait(); // block until `notify()` is called
assert_eq!(VALUE.load(Ordering::Relaxed), 1);

Implementations

impl WaitQueue

pub const fn new() -> Self

Creates an empty wait queue.

pub fn with_capacity(capacity: usize) -> Self

Creates an empty wait queue with space for at least capacity elements.

pub fn wait(&self)

Blocks the current task and put it into the wait queue, until other task notifies it.

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

where F: Fn() -> bool,

Blocks the current task and put it into the wait queue, until the given condition becomes true.

Note that even other tasks notify this task, it will not wake up until the condition becomes true.

pub fn wait_timeout(&self, dur: Duration) -> bool

Available on crate feature irq only.

Blocks the current task and put it into the wait queue, until other tasks notify it, or the given duration has elapsed.

pub fn wait_timeout_until<F>(&self, dur: Duration, condition: F) -> bool

where F: Fn() -> bool,

Available on crate feature irq only.

Blocks the current task and put it into the wait queue, until the given condition becomes true, or the given duration has elapsed.

Note that even other tasks notify this task, it will not wake up until the above conditions are met.

pub fn notify_one(&self, resched: bool) -> bool

Wakes up one task in the wait queue, usually the first one.

If resched is true, the current task will be preempted when the preemption is enabled.

pub fn notify_all(&self, resched: bool)

Wakes all tasks in the wait queue.

If resched is true, the current task will be preempted when the preemption is enabled.

pub fn notify_task(&mut self, resched: bool, task: &AxTaskRef) -> bool

Wake up the given task in the wait queue.

If resched is true, the current task will be preempted when the preemption is enabled.