Trait SpawnExt

pub trait SpawnExt: Spawn {
    // Provided methods
    fn spawn<Fut>(&self, future: Fut) -> Result<(), SpawnError>
       where Fut: Future<Output = ()> + Send + 'static { ... }
    fn spawn_with_handle<Fut>(
        &self,
        future: Fut,
    ) -> Result<RemoteHandle<Fut::Output>, SpawnError>
       where Fut: Future + Send + 'static,
             Fut::Output: Send { ... }
}

Extension trait for Spawn.

Provided Methods

fn spawn<Fut>(&self, future: Fut) -> Result<(), SpawnError>

where Fut: Future<Output = ()> + Send + 'static,

Spawns a task that polls the given future with output () to completion.

This method returns a Result that contains a SpawnError if spawning fails.

You can use spawn_with_handle if you want to spawn a future with output other than () or if you want to be able to await its completion.

Note this method will eventually be replaced with the upcoming Spawn::spawn method which will take a dyn Future as input. Technical limitations prevent Spawn::spawn from being implemented today. Feel free to use this method in the meantime.

use futures::executor::ThreadPool;
use futures::task::SpawnExt;

let executor = ThreadPool::new().unwrap();

let future = async { /* ... */ };
executor.spawn(future).unwrap();

fn spawn_with_handle<Fut>( &self, future: Fut, ) -> Result<RemoteHandle<Fut::Output>, SpawnError>

where Fut: Future + Send + 'static, Fut::Output: Send,

Spawns a task that polls the given future to completion and returns a future that resolves to the spawned future’s output.

This method returns a Result that contains a RemoteHandle, or, if spawning fails, a SpawnError. RemoteHandle is a future that resolves to the output of the spawned future.

use futures::executor::{block_on, ThreadPool};
use futures::future;
use futures::task::SpawnExt;

let executor = ThreadPool::new().unwrap();

let future = future::ready(1);
let join_handle_fut = executor.spawn_with_handle(future).unwrap();
assert_eq!(block_on(join_handle_fut), 1);

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<Sp> SpawnExt for Sp

where Sp: Spawn + ?Sized,