<!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 `copy` fn in crate `std`."> <meta name="keywords" content="rust, rustlang, rust-lang, copy"> <title>std::fs::copy - 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="../../main.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> <p class='location'><a href='../index.html'>std</a>::<wbr><a href='index.html'>fs</a></p><script>window.sidebarCurrent = {name: 'copy', ty: 'fn', relpath: ''};</script><script defer src="sidebar-items.js"></script> </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"> </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'>fs</a>::<wbr><a class="fn" href=''>copy</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/fs.rs.html#1553-1555' title='goto source code'>[src]</a></span></h1> <pre class='rust fn'>pub fn copy<P: <a class="trait" href="../../std/convert/trait.AsRef.html" title="trait std::convert::AsRef">AsRef</a><<a class="struct" href="../../std/path/struct.Path.html" title="struct std::path::Path">Path</a>>, Q: <a class="trait" href="../../std/convert/trait.AsRef.html" title="trait std::convert::AsRef">AsRef</a><<a class="struct" href="../../std/path/struct.Path.html" title="struct std::path::Path">Path</a>>>(from: P, to: Q) -> <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 class='docblock'><p>Copies the contents of one file to another. This function will also copy the permission bits of the original file to the destination file.</p> <p>This function will <strong>overwrite</strong> the contents of <code>to</code>.</p> <p>Note that if <code>from</code> and <code>to</code> both point to the same file, then the file will likely get truncated by this operation.</p> <p>On success, the total number of bytes copied is returned and it is equal to the length of the <code>to</code> file as reported by <code>metadata</code>.</p> <h1 id="platform-specific-behavior" class="section-header"><a href="#platform-specific-behavior">Platform-specific behavior</a></h1> <p>This function currently corresponds to the <code>open</code> function in Unix with <code>O_RDONLY</code> for <code>from</code> and <code>O_WRONLY</code>, <code>O_CREAT</code>, and <code>O_TRUNC</code> for <code>to</code>. <code>O_CLOEXEC</code> is set for returned file descriptors. On Windows, this function currently corresponds to <code>CopyFileEx</code>. Alternate NTFS streams are copied but only the size of the main stream is returned by this function. Note that, this <a href="../io/index.html#platform-specific-behavior">may change in the future</a>.</p> <h1 id="errors" class="section-header"><a href="#errors">Errors</a></h1> <p>This function will return an error in the following situations, but is not limited to just these cases:</p> <ul> <li>The <code>from</code> path is not a file.</li> <li>The <code>from</code> file does not exist.</li> <li>The current process does not have the permission rights to access <code>from</code> or write <code>to</code>.</li> </ul> <h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1> <pre class="rust rust-example-rendered"> <span class="kw">use</span> <span class="ident">std</span>::<span class="ident">fs</span>; <span class="ident">fs</span>::<span class="ident">copy</span>(<span class="string">"foo.txt"</span>, <span class="string">"bar.txt"</span>)<span class="question-mark">?</span>; <span class="comment">// Copy foo.txt to bar.txt</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%3Afs%3B%0A%0Afn%20foo()%20-%3E%20std%3A%3Aio%3A%3AResult%3C()%3E%20%7B%0Afs%3A%3Acopy(%22foo.txt%22%2C%20%22bar.txt%22)%3F%3B%20%20%2F%2F%20Copy%20foo.txt%20to%20bar.txt%0AOk(())%20%7D%0A%7D">Run</a></pre> </div></section> <section id='search' class="content hidden"></section> <section class="footer"></section> <aside id="help" class="hidden"> <div> <h1 class="hidden">Help</h1> <div class="shortcuts"> <h2>Keyboard Shortcuts</h2> <dl> <dt><kbd>?</kbd></dt> <dd>Show this help dialog</dd> <dt><kbd>S</kbd></dt> <dd>Focus the search field</dd> <dt><kbd>↑</kbd></dt> <dd>Move up in search results</dd> <dt><kbd>↓</kbd></dt> <dd>Move down in search results</dd> <dt><kbd>↹</kbd></dt> <dd>Switch tab</dd> <dt><kbd>⏎</kbd></dt> <dd>Go to active search result</dd> <dt><kbd>+</kbd></dt> <dd>Expand all sections</dd> <dt><kbd>-</kbd></dt> <dd>Collapse all sections</dd> </dl> </div> <div class="infos"> <h2>Search Tricks</h2> <p> Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type. </p> <p> Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>. </p> <p> Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>) </p> </div> </div> </aside> <script> window.rootPath = "../../"; window.currentCrate = "std"; </script> <script src="../../main.js"></script> <script defer src="../../search-index.js"></script> </body> </html>