Struct JoinHandle 

pub struct JoinHandle<T>(/* private fields */);

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

This can be thought of as the equivalent of std::thread::JoinHandle for a crate::LocalSpawnPool task rather than a thread. You do not need to .await the JoinHandle to make the task execute — it will start running in the background immediately. When awaiting the JoinHandle<T>, you will obtain an Option<T>, where T is the output of the spawned future associated with this handle: it will be None if the task was aborted.

A JoinHandle detaches the associated task when it is dropped, which means that there is no longer any handle to the task, and no way to join on it.

This struct is created by the crate::LocalSpawnPool::spawn and crate::spawn functions.

Cancel safety

The JoinHandle<T> type is cancel safe. If it is used as the event in a tokio::select! statement and some other branch completes first, then it is guaranteed that the output of the task is not lost.

If a JoinHandle is dropped, then the task continues running in the background and its return value is lost.

Implementations

impl<T> JoinHandle<T>

pub fn abort(&self)

Aborts the task associated with the handle.

pub fn is_finished(&self) -> bool

Returns true if the task has finished executing. If the task was aborted before finishing execution, it returns false.

pub fn is_aborted(&self) -> bool

Returns true if the task has been aborted. If JoinHandle::abort was called after the task finished executing, it still returns false.

Trait Implementations

impl<T> Future for JoinHandle<T>

type Output = Option<T>

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.