Struct async_std::task::JoinHandle

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

A handle that awaits the result of a task.

Dropping a JoinHandle will detach the task, meaning that there is no longer a handle to the task and no way to join on it.

Created when a task is spawned.

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impl<T> JoinHandle<T>

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pub fn task(&self) -> &Task

Returns a handle to the underlying task.

§Examples
use async_std::task;

let handle = task::spawn(async {
    1 + 2
});
println!("id = {}", handle.task().id());
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pub async fn cancel(self) -> Option<T>

Cancel this task.

Trait Implementations§

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impl<T: Debug> Debug for JoinHandle<T>

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

Formats the value using the given formatter. Read more
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impl<T> Drop for JoinHandle<T>

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fn drop(&mut self)

Executes the destructor for this type. Read more
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impl<T> Future for JoinHandle<T>

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type Output = T

The type of value produced on completion.
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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. Read more

Auto Trait Implementations§

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impl<T> Freeze for JoinHandle<T>

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impl<T> RefUnwindSafe for JoinHandle<T>

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impl<T> Send for JoinHandle<T>
where T: Send,

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impl<T> Sync for JoinHandle<T>

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impl<T> Unpin for JoinHandle<T>

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impl<T> UnwindSafe for JoinHandle<T>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<F> FutureExt for F
where F: Future + ?Sized,

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

A convenience for calling Future::poll() on !Unpin types.
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fn or<F>(self, other: F) -> Or<Self, F>
where Self: Sized, F: Future<Output = Self::Output>,

Returns the result of self or other future, preferring self if both are ready. Read more
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fn race<F>(self, other: F) -> Race<Self, F>
where Self: Sized, F: Future<Output = Self::Output>,

Returns the result of self or other future, with no preference if both are ready. Read more
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fn catch_unwind(self) -> CatchUnwind<Self>
where Self: Sized + UnwindSafe,

Catches panics while polling the future. Read more
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fn boxed<'a>(self) -> Pin<Box<dyn Future<Output = Self::Output> + Send + 'a>>
where Self: Sized + Send + 'a,

Boxes the future and changes its type to dyn Future + Send + 'a. Read more
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fn boxed_local<'a>(self) -> Pin<Box<dyn Future<Output = Self::Output> + 'a>>
where Self: Sized + 'a,

Boxes the future and changes its type to dyn Future + 'a. Read more
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impl<T> FutureExt for T
where T: Future + ?Sized,

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fn delay(self, dur: Duration) -> DelayFuture<Self>
where Self: Sized,

Available on unstable only.
Returns a Future that delays execution for a specified time. Read more
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fn flatten(self) -> FlattenFuture<Self, <Self::Output as IntoFuture>::Future>
where Self: Sized, <Self as Future>::Output: IntoFuture,

Available on unstable only.
Flatten out the execution of this future when the result itself can be converted into another future. Read more
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fn race<F>(self, other: F) -> Race<Self, F>
where Self: Future + Sized, F: Future<Output = <Self as Future>::Output>,

Available on unstable only.
Waits for one of two similarly-typed futures to complete. Read more
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fn try_race<F, T, E>(self, other: F) -> TryRace<Self, F>
where Self: Future<Output = Result<T, E>> + Sized, F: Future<Output = <Self as Future>::Output>,

Available on unstable only.
Waits for one of two similarly-typed fallible futures to complete. Read more
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fn join<F>(self, other: F) -> Join<Self, F>
where Self: Future + Sized, F: Future,

Available on unstable only.
Waits for two similarly-typed futures to complete. Read more
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fn try_join<F, A, B, E>(self, other: F) -> TryJoin<Self, F>
where Self: Future<Output = Result<A, E>> + Sized, F: Future<Output = Result<B, E>>,

Available on unstable only.
Waits for two similarly-typed fallible futures to complete. Read more
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fn timeout(self, dur: Duration) -> TimeoutFuture<Self>
where Self: Sized,

Available on unstable only.
Waits for both the future and a timeout, if the timeout completes before the future, it returns a TimeoutError. Read more
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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<F> IntoFuture for F
where F: Future,

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type Output = <F as Future>::Output

The output that the future will produce on completion.
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type IntoFuture = F

Which kind of future are we turning this into?
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fn into_future(self) -> <F as IntoFuture>::IntoFuture

Creates a future from a value. Read more
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impl<T> IntoFuture for T
where T: Future,

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type Output = <T as Future>::Output

Available on unstable only.
The type of value produced on completion.
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type Future = T

Available on unstable only.
Which kind of future are we turning this into?
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fn into_future(self) -> <T as IntoFuture>::Future

Available on unstable only.
Create a future from a value
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<F, T, E> TryFuture for F
where F: Future<Output = Result<T, E>> + ?Sized,

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type Ok = T

The type of successful values yielded by this future
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type Error = E

The type of failures yielded by this future
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fn try_poll( self: Pin<&mut F>, cx: &mut Context<'_>, ) -> Poll<<F as Future>::Output>

Poll this TryFuture as if it were a Future. Read more
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more