Function futures_util::future::join_all

source · 
pub fn join_all<I>(iter: I) -> JoinAll<I::Item> ⓘ
where
    I: IntoIterator,
    I::Item: Future,
Expand description

Creates a future which represents a collection of the outputs 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.

This function is only available when the std or alloc feature of this library is activated, and it is activated by default.

§See Also

join_all will switch to the more powerful FuturesOrdered for performance reasons if the number of futures is large. You may want to look into using it or it’s counterpart FuturesUnordered directly.

Some examples for additional functionality provided by these are:

  • Adding new futures to the set even after it has been started.

  • Only polling the specific futures that have been woken. In cases where you have a lot of futures this will result in much more efficient polling.

§Examples

use futures::future::join_all;

async fn foo(i: u32) -> u32 { i }

let futures = vec![foo(1), foo(2), foo(3)];

assert_eq!(join_all(futures).await, [1, 2, 3]);