<!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="API documentation for the Rust `empty` fn in crate `std`."><meta name="keywords" content="rust, rustlang, rust-lang, empty"><title>std::io::empty - Rust</title><link rel="stylesheet" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../dark.css"><link rel="stylesheet" type="text/css" href="../../light.css" id="themeStyle"><script src="../../storage.js"></script><link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"></head><body class="rustdoc fn"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../std/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a><div class="sidebar-elems"><p class='location'><a href='../index.html'>std</a>::<wbr><a href='index.html'>io</a></p><script>window.sidebarCurrent = {name: 'empty', ty: 'fn', relpath: ''};</script><script defer src="sidebar-items.js"></script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><a id="settings-menu" href="../../settings.html"><img src="../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class='fqn'><span class='in-band'>Function <a href='../index.html'>std</a>::<wbr><a href='index.html'>io</a>::<wbr><a class="fn" href=''>empty</a></span><span class='out-of-band'><span class='since' title='Stable since Rust version 1.0.0'>1.0.0</span><span id='render-detail'><a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class='inner'>−</span>]</a></span><a class='srclink' href='../../src/std/io/util.rs.html#97' title='goto source code'>[src]</a></span></h1><div class="important-traits"><div class='tooltip'>ⓘ<span class='tooltiptext'>Important traits for <a class="struct" href="../../std/io/struct.Empty.html" title="struct std::io::Empty">Empty</a></span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="../../std/io/struct.Empty.html" title="struct std::io::Empty">Empty</a></h3><code class="content"><span class="where fmt-newline">impl <a class="trait" href="../../std/io/trait.Read.html" title="trait std::io::Read">Read</a> for <a class="struct" href="../../std/io/struct.Empty.html" title="struct std::io::Empty">Empty</a></span></code></div></div><pre class='rust fn'>pub fn empty() -> <a class="struct" href="../../std/io/struct.Empty.html" title="struct std::io::Empty">Empty</a></pre><div class='docblock'><p>Constructs a new handle to an empty reader.</p>
<p>All reads from the returned reader will return <a href="../result/enum.Result.html#variant.Ok"><code>Ok</code></a><code>(0)</code>.</p>
<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
<p>A slightly sad example of not reading anything into a buffer:</p>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">io</span>::{<span class="self">self</span>, <span class="ident">Read</span>};
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">new</span>();
<span class="ident">io</span>::<span class="ident">empty</span>().<span class="ident">read_to_string</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buffer</span>).<span class="ident">unwrap</span>();
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">buffer</span>.<span class="ident">is_empty</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Aio%3A%3A%7Bself%2C%20Read%7D%3B%0A%0Alet%20mut%20buffer%20%3D%20String%3A%3Anew()%3B%0Aio%3A%3Aempty().read_to_string(%26mut%20buffer).unwrap()%3B%0Aassert!(buffer.is_empty())%3B%0A%7D">Run</a></pre>
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