<!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 `Seek` trait in crate `std`."><meta name="keywords" content="rust, rustlang, rust-lang, Seek"><title>std::io::Seek - 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 trait"><!--[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><p class='location'>Trait Seek</p><div class="sidebar-elems"><div class="block items"><a class="sidebar-title" href="#required-methods">Required Methods</a><div class="sidebar-links"><a href="#tymethod.seek">seek</a></div><a class="sidebar-title" href="#implementors">Implementors</a></div><p class='location'><a href='../index.html'>std</a>::<wbr><a href='index.html'>io</a></p><script>window.sidebarCurrent = {name: 'Seek', ty: 'trait', 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'>Trait <a href='../index.html'>std</a>::<wbr><a href='index.html'>io</a>::<wbr><a class="trait" href=''>Seek</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/mod.rs.html#1247-1264' title='goto source code'>[src]</a></span></h1><div class="docblock type-decl"><pre class='rust trait'>pub trait Seek {
fn <a href='#tymethod.seek' class='fnname'>seek</a>(&mut self, pos: <a class="enum" href="../../std/io/enum.SeekFrom.html" title="enum std::io::SeekFrom">SeekFrom</a>) -> <a class="type" href="../../std/io/type.Result.html" title="type std::io::Result">Result</a><<a class="primitive" href="../primitive.u64.html">u64</a>>;
}</pre></div><div class='docblock'><p>The <code>Seek</code> trait provides a cursor which can be moved within a stream of
bytes.</p>
<p>The stream typically has a fixed size, allowing seeking relative to either
end or the current offset.</p>
<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
<p><a href="../fs/struct.File.html"><code>File</code></a>s implement <code>Seek</code>:</p>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">io</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">io</span>::<span class="ident">prelude</span>::<span class="kw-2">*</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">fs</span>::<span class="ident">File</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">io</span>::<span class="ident">SeekFrom</span>;
<span class="kw">fn</span> <span class="ident">main</span>() <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> {
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">f</span> <span class="op">=</span> <span class="ident">File</span>::<span class="ident">open</span>(<span class="string">"foo.txt"</span>)<span class="question-mark">?</span>;
<span class="comment">// move the cursor 42 bytes from the start of the file</span>
<span class="ident">f</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Start</span>(<span class="number">42</span>))<span class="question-mark">?</span>;
<span class="prelude-val">Ok</span>(())
}<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Ause%20std%3A%3Aio%3B%0Ause%20std%3A%3Aio%3A%3Aprelude%3A%3A*%3B%0Ause%20std%3A%3Afs%3A%3AFile%3B%0Ause%20std%3A%3Aio%3A%3ASeekFrom%3B%0A%0Afn%20main()%20-%3E%20io%3A%3AResult%3C()%3E%20%7B%0A%20%20%20%20let%20mut%20f%20%3D%20File%3A%3Aopen(%22foo.txt%22)%3F%3B%0A%0A%20%20%20%20%2F%2F%20move%20the%20cursor%2042%20bytes%20from%20the%20start%20of%20the%20file%0A%20%20%20%20f.seek(SeekFrom%3A%3AStart(42))%3F%3B%0A%20%20%20%20Ok(())%0A%7D">Run</a></pre>
</div>
<h2 id='required-methods' class='small-section-header'>
Required Methods<a href='#required-methods' class='anchor'></a>
</h2>
<div class='methods'>
<h3 id='tymethod.seek' class='method'><span id='seek.v' class='invisible'><code>fn <a href='#tymethod.seek' class='fnname'>seek</a>(&mut self, pos: <a class="enum" href="../../std/io/enum.SeekFrom.html" title="enum std::io::SeekFrom">SeekFrom</a>) -> <a class="type" href="../../std/io/type.Result.html" title="type std::io::Result">Result</a><<a class="primitive" href="../primitive.u64.html">u64</a>></code></span></h3><div class='docblock'><p>Seek to an offset, in bytes, in a stream.</p>
<p>A seek beyond the end of a stream is allowed, but implementation
defined.</p>
<p>If the seek operation completed successfully,
this method returns the new position from the start of the stream.
That position can be used later with <a href="enum.SeekFrom.html#variant.Start"><code>SeekFrom::Start</code></a>.</p>
<h1 id="errors" class="section-header"><a href="#errors">Errors</a></h1>
<p>Seeking to a negative offset is considered an error.</p>
</div></div>
<h2 id='implementors' class='small-section-header'>
Implementors<a href='#implementors' class='anchor'></a>
</h2>
<ul class='item-list' id='implementors-list'>
<li><table class='table-display'><tbody><tr><td><code>impl Seek for <a class="struct" href="../../std/fs/struct.File.html" title="struct std::fs::File">File</a></code><td><div class='out-of-band'><a class='srclink' href='../../src/std/fs.rs.html#624-628' title='goto source code'>[src]</a></div></td></tr></tbody></table></li>
<li><table class='table-display'><tbody><tr><td><code>impl<'a> Seek for &'a <a class="struct" href="../../std/fs/struct.File.html" title="struct std::fs::File">File</a></code><td><div class='out-of-band'><a class='srclink' href='../../src/std/fs.rs.html#648-652' title='goto source code'>[src]</a></div></td></tr></tbody></table></li>
<li><table class='table-display'><tbody><tr><td><code>impl<R: <a class="trait" href="../../std/io/trait.Seek.html" title="trait std::io::Seek">Seek</a>> Seek for <a class="struct" href="../../std/io/struct.BufReader.html" title="struct std::io::BufReader">BufReader</a><R></code><td><div class='out-of-band'><a class='srclink' href='../../src/std/io/buffered.rs.html#311-358' title='goto source code'>[src]</a></div></td></tr></tbody></table></li>
<li><table class='table-display'><tbody><tr><td><code>impl<W: <a class="trait" href="../../std/io/trait.Write.html" title="trait std::io::Write">Write</a> + <a class="trait" href="../../std/io/trait.Seek.html" title="trait std::io::Seek">Seek</a>> Seek for <a class="struct" href="../../std/io/struct.BufWriter.html" title="struct std::io::BufWriter">BufWriter</a><W></code><td><div class='out-of-band'><a class='srclink' href='../../src/std/io/buffered.rs.html#614-621' title='goto source code'>[src]</a></div></td></tr></tbody></table></li>
<li><table class='table-display'><tbody><tr><td><code>impl<T> Seek for <a class="struct" href="../../std/io/struct.Cursor.html" title="struct std::io::Cursor">Cursor</a><T> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../std/convert/trait.AsRef.html" title="trait std::convert::AsRef">AsRef</a><<a class="primitive" href="../primitive.slice.html">[</a><a class="primitive" href="../primitive.u8.html">u8</a><a class="primitive" href="../primitive.slice.html">]</a>>, </span></code><td><div class='out-of-band'><a class='srclink' href='../../src/std/io/cursor.rs.html#204-222' title='goto source code'>[src]</a></div></td></tr></tbody></table></li>
<li><table class='table-display'><tbody><tr><td><code>impl<'a, S: <a class="trait" href="../../std/io/trait.Seek.html" title="trait std::io::Seek">Seek</a> + ?<a class="trait" href="../../std/marker/trait.Sized.html" title="trait std::marker::Sized">Sized</a>> Seek for <a class="primitive" href="../primitive.reference.html">&'a mut </a>S</code><td><div class='out-of-band'><a class='srclink' href='../../src/std/io/impls.rs.html#65-68' title='goto source code'>[src]</a></div></td></tr></tbody></table></li>
<li><table class='table-display'><tbody><tr><td><code>impl<S: <a class="trait" href="../../std/io/trait.Seek.html" title="trait std::io::Seek">Seek</a> + ?<a class="trait" href="../../std/marker/trait.Sized.html" title="trait std::marker::Sized">Sized</a>> Seek for <a class="struct" href="../../std/boxed/struct.Box.html" title="struct std::boxed::Box">Box</a><S></code><td><div class='out-of-band'><a class='srclink' href='../../src/std/io/impls.rs.html#134-137' title='goto source code'>[src]</a></div></td></tr></tbody></table></li>
</ul><script type="text/javascript">window.inlined_types=new Set([]);</script><script type="text/javascript" async
src="../../implementors/std/io/trait.Seek.js">
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