Function join_all

pub fn join_all<I>(
    i: I,
) -> JoinAll<<<I as IntoIterator>::Item as IntoFuture>::Future>
where
    I: IntoIterator,
    <I as IntoIterator>::Item: IntoFuture,

Creates a future which represents a collection of the results of the futures given.

The returned future will drive execution for all of its underlying futures, collecting the results into a destination Vec<T> in the same order as they were provided. If any future returns an error then all other futures will be canceled and an error will be returned immediately. If all futures complete successfully, however, then the returned future will succeed with a Vec of all the successful results.

Examples

use futures::prelude::*;
use futures::future::{join_all, ok, err};

let f = join_all(vec![
    ok::<u32, u32>(1),
    ok::<u32, u32>(2),
    ok::<u32, u32>(3),
]);
let f = f.map(|x| {
    assert_eq!(x, [1, 2, 3]);
});

let f = join_all(vec![
    Box::new(ok::<u32, u32>(1)),
    Box::new(err::<u32, u32>(2)),
    Box::new(ok::<u32, u32>(3)),
]);
let f = f.then(|x| {
    assert_eq!(x, Err(2));
    x
});