Struct tokio::task::JoinHandle [−][src]
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 task rather than a thread.
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 task::spawn
and task::spawn_blocking
functions.
Examples
Creation from task::spawn
:
use tokio::task; let join_handle: task::JoinHandle<_> = task::spawn(async { // some work here });
Creation from task::spawn_blocking
:
use tokio::task; let join_handle: task::JoinHandle<_> = task::spawn_blocking(|| { // some blocking work here });
Child being detached and outliving its parent:
use tokio::task; use tokio::time; use std::time::Duration; let original_task = task::spawn(async { let _detached_task = task::spawn(async { // Here we sleep to make sure that the first task returns before. time::delay_for(Duration::from_millis(10)).await; // This will be called, even though the JoinHandle is dropped. println!("♫ Still alive ♫"); }); }); original_task.await.expect("The task being joined has panicked"); println!("Original task is joined."); // We make sure that the new task has time to run, before the main // task returns. time::delay_for(Duration::from_millis(1000)).await;
Trait Implementations
impl<T> Debug for JoinHandle<T> where
T: Debug,
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T: Debug,
impl<T> Drop for JoinHandle<T>
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impl<T> Future for JoinHandle<T>
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type Output = Result<T, JoinError>
The type of value produced on completion.
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>
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impl<T: Send> Send for JoinHandle<T>
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impl<T: Send> Sync for JoinHandle<T>
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impl<T> Unpin for JoinHandle<T>
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Auto Trait Implementations
impl<T> !RefUnwindSafe for JoinHandle<T>
impl<T> !UnwindSafe for JoinHandle<T>
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut Tⓘ
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<F> IntoFuture for F where
F: Future,
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F: Future,
type Output = <F as Future>::Output
into_future
)The output that the future will produce on completion.
type Future = F
into_future
)Which kind of future are we turning this into?
pub fn into_future(self) -> <F as IntoFuture>::Future
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<F, T, E> TryFuture for F where
F: Future<Output = Result<T, E>> + ?Sized,
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F: Future<Output = Result<T, E>> + ?Sized,
type Ok = T
The type of successful values yielded by this future
type Error = E
The type of failures yielded by this future
pub fn try_poll(
self: Pin<&mut F>,
cx: &mut Context<'_>
) -> Poll<<F as Future>::Output>
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self: Pin<&mut F>,
cx: &mut Context<'_>
) -> Poll<<F as Future>::Output>
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,