Function futures::future::try_join_all

source · 
pub fn try_join_all<I>(iter: I) -> TryJoinAll<<I as IntoIterator>::Item> ⓘ
where
    I: IntoIterator,
    <I as IntoIterator>::Item: TryFuture,
Expand description

Creates a future which represents either a collection of the results of the futures given or an error.

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.

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

See Also

try_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::{self, try_join_all};

let futures = vec![
    future::ok::<u32, u32>(1),
    future::ok::<u32, u32>(2),
    future::ok::<u32, u32>(3),
];

assert_eq!(try_join_all(futures).await, Ok(vec![1, 2, 3]));

let futures = vec![
    future::ok::<u32, u32>(1),
    future::err::<u32, u32>(2),
    future::ok::<u32, u32>(3),
];

assert_eq!(try_join_all(futures).await, Err(2));