Function futures_util::future::poll_fn

source · [−]

pub fn poll_fn<T, F>(f: F) -> PollFn<F>ⓘNotable traits for PollFn<F>impl<T, F> Future for PollFn<F> where
    F: FnMut(&mut Context<'_>) -> Poll<T>,     type Output = T; where
    F: FnMut(&mut Context<'_>) -> Poll<T>,

Expand description

Creates a new future wrapping around a function returning Poll.

Polling the returned future delegates to the wrapped function.

Examples

use futures::future::poll_fn;
use futures::task::{Context, Poll};

fn read_line(_cx: &mut Context<'_>) -> Poll<String> {
    Poll::Ready("Hello, World!".into())
}

let read_future = poll_fn(read_line);
assert_eq!(read_future.await, "Hello, World!".to_owned());