core::future::poll_fn - Rust
Description: API documentation for the Rust `poll_fn` fn in crate `core`.
Keywords: rust, rustlang, rust-lang, poll_fn

# [−][src]Function core::future::poll_fn

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    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>,

🔬 This is a nightly-only experimental API. (`future_poll_fn` #72302)

Creates a future that wraps a function returning `Poll`.

Polling the future delegates to the wrapped function.

# Examples

    #![feature(future_poll_fn)]
    use core::future::poll_fn;
    use std::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());

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