| <!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="Write bytes asynchronously."><meta name="keywords" content="rust, rustlang, rust-lang, AsyncWrite"><title>AsyncWrite in futures_io - Rust</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="sidebar-items.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 trait"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">☰</button><a class="sidebar-logo" href="../futures_io/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../futures_io/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><h2 class="location"><a href="#">AsyncWrite</a></h2><div class="sidebar-elems"><section><h3><a href="#required-methods">Required Methods</a></h3><ul class="block"><li><a href="#tymethod.poll_close">poll_close</a></li><li><a href="#tymethod.poll_flush">poll_flush</a></li><li><a href="#tymethod.poll_write">poll_write</a></li></ul><h3><a href="#provided-methods">Provided Methods</a></h3><ul class="block"><li><a href="#method.poll_write_vectored">poll_write_vectored</a></li></ul><h3><a href="#foreign-impls">Implementations on Foreign Types</a></h3><ul class="block"><li><a href="#impl-AsyncWrite-for-%26mut%20T">&mut T</a></li><li><a href="#impl-AsyncWrite-for-Box%3CT%3E">Box<T></a></li><li><a href="#impl-AsyncWrite-for-Pin%3CP%3E">Pin<P></a></li><li><a href="#impl-AsyncWrite-for-Vec%3Cu8%3E">Vec<u8></a></li></ul><h3><a href="#implementors">Implementors</a></h3></section><h2><a href="index.html">In futures_io</a></h2></div></nav><main><div class="width-limiter"><nav class="sub"><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="main-heading"><h1 class="fqn">Trait <a href="index.html">futures_io</a>::<wbr><a class="trait" href="#">AsyncWrite</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../src/futures_io/lib.rs.html#110-208">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="item-decl"><pre class="rust trait"><code>pub trait AsyncWrite { |
| fn <a href="#tymethod.poll_write" class="fnname">poll_write</a>(<br> self: Pin<&mut Self>,<br> cx: &mut Context<'_>,<br> buf: &[u8]<br> ) -> Poll<Result<usize>>; |
| <span class="item-spacer"></span> fn <a href="#tymethod.poll_flush" class="fnname">poll_flush</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>; |
| <span class="item-spacer"></span> fn <a href="#tymethod.poll_close" class="fnname">poll_close</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>; |
| |
| fn <a href="#method.poll_write_vectored" class="fnname">poll_write_vectored</a>(<br> self: Pin<&mut Self>,<br> cx: &mut Context<'_>,<br> bufs: &[IoSlice<'_>]<br> ) -> Poll<Result<usize>> { ... } |
| }</code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Write bytes asynchronously.</p> |
| <p>This trait is analogous to the <code>std::io::Write</code> trait, but integrates |
| with the asynchronous task system. In particular, the <code>poll_write</code> |
| method, unlike <code>Write::write</code>, will automatically queue the current task |
| for wakeup and return if the writer cannot take more data, rather than blocking |
| the calling thread.</p> |
| </div></details><h2 id="required-methods" class="small-section-header">Required Methods<a href="#required-methods" class="anchor"></a></h2><div class="methods"><details class="rustdoc-toggle method-toggle" open><summary><section id="tymethod.poll_write" class="method has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#129-133">source</a><h4 class="code-header">fn <a href="#tymethod.poll_write" class="fnname">poll_write</a>(<br> self: Pin<&mut Self>,<br> cx: &mut Context<'_>,<br> buf: &[u8]<br>) -> Poll<Result<usize>></h4></section></summary><div class="docblock"><p>Attempt to write bytes from <code>buf</code> into the object.</p> |
| <p>On success, returns <code>Poll::Ready(Ok(num_bytes_written))</code>.</p> |
| <p>If the object is not ready for writing, the method returns |
| <code>Poll::Pending</code> and arranges for the current task (via |
| <code>cx.waker().wake_by_ref()</code>) to receive a notification when the object becomes |
| writable or is closed.</p> |
| <h5 id="implementation"><a href="#implementation">Implementation</a></h5> |
| <p>This function may not return errors of kind <code>WouldBlock</code> or |
| <code>Interrupted</code>. Implementations must convert <code>WouldBlock</code> into |
| <code>Poll::Pending</code> and either internally retry or convert |
| <code>Interrupted</code> into another error kind.</p> |
| <p><code>poll_write</code> must try to make progress by flushing the underlying object if |
| that is the only way the underlying object can become writable again.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="tymethod.poll_flush" class="method has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#190">source</a><h4 class="code-header">fn <a href="#tymethod.poll_flush" class="fnname">poll_flush</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>></h4></section></summary><div class="docblock"><p>Attempt to flush the object, ensuring that any buffered data reach |
| their destination.</p> |
| <p>On success, returns <code>Poll::Ready(Ok(()))</code>.</p> |
| <p>If flushing cannot immediately complete, this method returns |
| <code>Poll::Pending</code> and arranges for the current task (via |
| <code>cx.waker().wake_by_ref()</code>) to receive a notification when the object can make |
| progress towards flushing.</p> |
| <h5 id="implementation-1"><a href="#implementation-1">Implementation</a></h5> |
| <p>This function may not return errors of kind <code>WouldBlock</code> or |
| <code>Interrupted</code>. Implementations must convert <code>WouldBlock</code> into |
| <code>Poll::Pending</code> and either internally retry or convert |
| <code>Interrupted</code> into another error kind.</p> |
| <p>It only makes sense to do anything here if you actually buffer data.</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="tymethod.poll_close" class="method has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#207">source</a><h4 class="code-header">fn <a href="#tymethod.poll_close" class="fnname">poll_close</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>></h4></section></summary><div class="docblock"><p>Attempt to close the object.</p> |
| <p>On success, returns <code>Poll::Ready(Ok(()))</code>.</p> |
| <p>If closing cannot immediately complete, this function returns |
| <code>Poll::Pending</code> and arranges for the current task (via |
| <code>cx.waker().wake_by_ref()</code>) to receive a notification when the object can make |
| progress towards closing.</p> |
| <h5 id="implementation-2"><a href="#implementation-2">Implementation</a></h5> |
| <p>This function may not return errors of kind <code>WouldBlock</code> or |
| <code>Interrupted</code>. Implementations must convert <code>WouldBlock</code> into |
| <code>Poll::Pending</code> and either internally retry or convert |
| <code>Interrupted</code> into another error kind.</p> |
| </div></details></div><h2 id="provided-methods" class="small-section-header">Provided Methods<a href="#provided-methods" class="anchor"></a></h2><div class="methods"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.poll_write_vectored" class="method has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#158-170">source</a><h4 class="code-header">fn <a href="#method.poll_write_vectored" class="fnname">poll_write_vectored</a>(<br> self: Pin<&mut Self>,<br> cx: &mut Context<'_>,<br> bufs: &[IoSlice<'_>]<br>) -> Poll<Result<usize>></h4></section></summary><div class="docblock"><p>Attempt to write bytes from <code>bufs</code> into the object using vectored |
| IO operations.</p> |
| <p>This method is similar to <code>poll_write</code>, but allows data from multiple buffers to be written |
| using a single operation.</p> |
| <p>On success, returns <code>Poll::Ready(Ok(num_bytes_written))</code>.</p> |
| <p>If the object is not ready for writing, the method returns |
| <code>Poll::Pending</code> and arranges for the current task (via |
| <code>cx.waker().wake_by_ref()</code>) to receive a notification when the object becomes |
| writable or is closed.</p> |
| <p>By default, this method delegates to using <code>poll_write</code> on the first |
| nonempty buffer in <code>bufs</code>, or an empty one if none exists. Objects which |
| support vectored IO should override this method.</p> |
| <h5 id="implementation-3"><a href="#implementation-3">Implementation</a></h5> |
| <p>This function may not return errors of kind <code>WouldBlock</code> or |
| <code>Interrupted</code>. Implementations must convert <code>WouldBlock</code> into |
| <code>Poll::Pending</code> and either internally retry or convert |
| <code>Interrupted</code> into another error kind.</p> |
| </div></details></div><h2 id="foreign-impls" class="small-section-header">Implementations on Foreign Types<a href="#foreign-impls" class="anchor"></a></h2><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-AsyncWrite-for-Box%3CT%3E" class="impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#402-404">source</a><a href="#impl-AsyncWrite-for-Box%3CT%3E" class="anchor"></a><h3 class="code-header">impl<T: ?Sized + <a class="trait" href="trait.AsyncWrite.html" title="trait futures_io::AsyncWrite">AsyncWrite</a> + Unpin> <a class="trait" href="trait.AsyncWrite.html" title="trait futures_io::AsyncWrite">AsyncWrite</a> for Box<T></h3></section></summary><div class="impl-items"><section id="method.poll_write" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#403">source</a><a href="#method.poll_write" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_write" class="fnname">poll_write</a>(<br> self: Pin<&mut Self>,<br> cx: &mut Context<'_>,<br> buf: &[u8]<br>) -> Poll<Result<usize>></h4></section><section id="method.poll_write_vectored-1" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#403">source</a><a href="#method.poll_write_vectored-1" class="anchor"></a><h4 class="code-header">fn <a href="#method.poll_write_vectored" class="fnname">poll_write_vectored</a>(<br> self: Pin<&mut Self>,<br> cx: &mut Context<'_>,<br> bufs: &[IoSlice<'_>]<br>) -> Poll<Result<usize>></h4></section><section id="method.poll_flush" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#403">source</a><a href="#method.poll_flush" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_flush" class="fnname">poll_flush</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>></h4></section><section id="method.poll_close" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#403">source</a><a href="#method.poll_close" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_close" class="fnname">poll_close</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>></h4></section></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-AsyncWrite-for-%26mut%20T" class="impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#406-408">source</a><a href="#impl-AsyncWrite-for-%26mut%20T" class="anchor"></a><h3 class="code-header">impl<T: ?Sized + <a class="trait" href="trait.AsyncWrite.html" title="trait futures_io::AsyncWrite">AsyncWrite</a> + Unpin> <a class="trait" href="trait.AsyncWrite.html" title="trait futures_io::AsyncWrite">AsyncWrite</a> for &mut T</h3></section></summary><div class="impl-items"><section id="method.poll_write-1" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#407">source</a><a href="#method.poll_write-1" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_write" class="fnname">poll_write</a>(<br> self: Pin<&mut Self>,<br> cx: &mut Context<'_>,<br> buf: &[u8]<br>) -> Poll<Result<usize>></h4></section><section id="method.poll_write_vectored-2" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#407">source</a><a href="#method.poll_write_vectored-2" class="anchor"></a><h4 class="code-header">fn <a href="#method.poll_write_vectored" class="fnname">poll_write_vectored</a>(<br> self: Pin<&mut Self>,<br> cx: &mut Context<'_>,<br> bufs: &[IoSlice<'_>]<br>) -> Poll<Result<usize>></h4></section><section id="method.poll_flush-1" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#407">source</a><a href="#method.poll_flush-1" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_flush" class="fnname">poll_flush</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>></h4></section><section id="method.poll_close-1" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#407">source</a><a href="#method.poll_close-1" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_close" class="fnname">poll_close</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>></h4></section></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-AsyncWrite-for-Pin%3CP%3E" class="impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#410-438">source</a><a href="#impl-AsyncWrite-for-Pin%3CP%3E" class="anchor"></a><h3 class="code-header">impl<P> <a class="trait" href="trait.AsyncWrite.html" title="trait futures_io::AsyncWrite">AsyncWrite</a> for Pin<P><span class="where fmt-newline">where<br> P: DerefMut + Unpin,<br> P::Target: <a class="trait" href="trait.AsyncWrite.html" title="trait futures_io::AsyncWrite">AsyncWrite</a>,</span></h3></section></summary><div class="impl-items"><section id="method.poll_write-2" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#415-421">source</a><a href="#method.poll_write-2" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_write" class="fnname">poll_write</a>(<br> self: Pin<&mut Self>,<br> cx: &mut Context<'_>,<br> buf: &[u8]<br>) -> Poll<Result<usize>></h4></section><section id="method.poll_write_vectored-3" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#423-429">source</a><a href="#method.poll_write_vectored-3" class="anchor"></a><h4 class="code-header">fn <a href="#method.poll_write_vectored" class="fnname">poll_write_vectored</a>(<br> self: Pin<&mut Self>,<br> cx: &mut Context<'_>,<br> bufs: &[IoSlice<'_>]<br>) -> Poll<Result<usize>></h4></section><section id="method.poll_flush-2" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#431-433">source</a><a href="#method.poll_flush-2" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_flush" class="fnname">poll_flush</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>></h4></section><section id="method.poll_close-2" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#435-437">source</a><a href="#method.poll_close-2" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_close" class="fnname">poll_close</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>></h4></section></div></details><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-AsyncWrite-for-Vec%3Cu8%3E" class="impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#468-470">source</a><a href="#impl-AsyncWrite-for-Vec%3Cu8%3E" class="anchor"></a><h3 class="code-header">impl <a class="trait" href="trait.AsyncWrite.html" title="trait futures_io::AsyncWrite">AsyncWrite</a> for Vec<u8></h3></section></summary><div class="impl-items"><section id="method.poll_write-3" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#469">source</a><a href="#method.poll_write-3" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_write" class="fnname">poll_write</a>(<br> self: Pin<&mut Self>,<br> _: &mut Context<'_>,<br> buf: &[u8]<br>) -> Poll<Result<usize>></h4></section><section id="method.poll_write_vectored-4" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#469">source</a><a href="#method.poll_write_vectored-4" class="anchor"></a><h4 class="code-header">fn <a href="#method.poll_write_vectored" class="fnname">poll_write_vectored</a>(<br> self: Pin<&mut Self>,<br> _: &mut Context<'_>,<br> bufs: &[IoSlice<'_>]<br>) -> Poll<Result<usize>></h4></section><section id="method.poll_flush-3" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#469">source</a><a href="#method.poll_flush-3" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_flush" class="fnname">poll_flush</a>(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<()>></h4></section><section id="method.poll_close-3" class="method trait-impl has-srclink"><a class="srclink rightside" href="../src/futures_io/lib.rs.html#469">source</a><a href="#method.poll_close-3" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.poll_close" class="fnname">poll_close</a>(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>></h4></section></div></details><h2 id="implementors" class="small-section-header">Implementors<a href="#implementors" class="anchor"></a></h2><div id="implementors-list"></div><script src="../implementors/futures_io/if_std/trait.AsyncWrite.js" data-ignore-extern-crates="alloc,core" async></script></section></div></main><div id="rustdoc-vars" data-root-path="../" data-current-crate="futures_io" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
