Struct JoinHandle

pub struct JoinHandle<T> { /* private fields */ }

An owned permission to join on a task (await its termination).

This can be seen as an equivalent to std::thread::JoinHandle but for Future tasks rather than a thread. Note that the task associated with this JoinHandle will start running at the time Executor::spawn is called as well as according to the implemented runtime (i.e. tokio), even if JoinHandle has not been awaited.

Dropping JoinHandle will not abort or cancel the task. In other words, the task will continue to run in the background and any return value will be lost.

This struct is created by the Executor::spawn.

Implementations

impl<T> JoinHandle<T>

pub fn empty() -> Self

Provide an empty JoinHandle with no associated task.

impl<T> JoinHandle<T>

pub fn abort(&self)

Abort the task associated with the handle.

pub fn is_finished(&self) -> bool

Check if the task associated with this JoinHandle has finished.

Note that this method can return false even if JoinHandle::abort has been called on the task due to the time it may take for the task to cancel.

pub unsafe fn replace(&mut self, handle: JoinHandle<T>)

Replace the current handle with the provided JoinHandle.

Safety

Note that if this is called with a non-empty handle, the existing task will not be terminated when it is replaced.

pub unsafe fn replace_in_place(&mut self, handle: &mut JoinHandle<T>)

Replace the current handle with the provided JoinHandle.

Safety

Note that if this is called with a non-empty handle, the existing task will not be terminated when it is replaced.

Trait Implementations

impl<T> Debug for JoinHandle<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> From<JoinHandle<T>> for AbortableJoinHandle<T>

fn from(handle: JoinHandle<T>) -> Self

Converts to this type from the input type.

impl<T> Future for JoinHandle<T>

type Output = Result<T, Error>

The type of value produced on completion.

fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>

Attempts to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.