| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/futures-util-0.3.28/src/async_await/pending.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>pending.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../futures_util/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../futures_util/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="kw">use </span>core::pin::Pin; |
| <span class="kw">use </span>futures_core::future::Future; |
| <span class="kw">use </span>futures_core::task::{Context, Poll}; |
| |
| <span class="doccomment">/// A macro which yields to the event loop once. |
| /// |
| /// This is equivalent to returning [`Poll::Pending`](futures_core::task::Poll) |
| /// from a [`Future::poll`](futures_core::future::Future::poll) implementation. |
| /// Similarly, when using this macro, it must be ensured that [`wake`](std::task::Waker::wake) |
| /// is called somewhere when further progress can be made. |
| /// |
| /// This macro is only usable inside of async functions, closures, and blocks. |
| /// It is also gated behind the `async-await` feature of this library, which is |
| /// activated by default. |
| </span><span class="attribute">#[macro_export] |
| </span><span class="macro">macro_rules! </span>pending { |
| () => { |
| <span class="macro-nonterminal">$crate::__private::async_await::pending_once</span>().<span class="kw">await |
| </span>}; |
| } |
| |
| <span class="attribute">#[doc(hidden)] |
| </span><span class="kw">pub fn </span>pending_once() -> PendingOnce { |
| PendingOnce { is_ready: <span class="bool-val">false </span>} |
| } |
| |
| <span class="attribute">#[allow(missing_debug_implementations)] |
| #[doc(hidden)] |
| </span><span class="kw">pub struct </span>PendingOnce { |
| is_ready: bool, |
| } |
| |
| <span class="kw">impl </span>Future <span class="kw">for </span>PendingOnce { |
| <span class="kw">type </span>Output = (); |
| <span class="kw">fn </span>poll(<span class="kw-2">mut </span><span class="self">self</span>: Pin<<span class="kw-2">&mut </span><span class="self">Self</span>>, <span class="kw">_</span>: <span class="kw-2">&mut </span>Context<<span class="lifetime">'_</span>>) -> Poll<<span class="self">Self</span>::Output> { |
| <span class="kw">if </span><span class="self">self</span>.is_ready { |
| Poll::Ready(()) |
| } <span class="kw">else </span>{ |
| <span class="self">self</span>.is_ready = <span class="bool-val">true</span>; |
| Poll::Pending |
| } |
| } |
| } |
| </code></pre></div> |
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