| <!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 `cfg_if` crate."> |
| <meta name="keywords" content="rust, rustlang, rust-lang, cfg_if"> |
| |
| <title>cfg_if - Rust</title> |
| |
| <link rel="stylesheet" type="text/css" href="../normalize.css"> |
| <link rel="stylesheet" type="text/css" href="../rustdoc.css"> |
| <link rel="stylesheet" type="text/css" href="../main.css"> |
| |
| |
| |
| |
| </head> |
| <body class="rustdoc mod"> |
| <!--[if lte IE 8]> |
| <div class="warning"> |
| This old browser is unsupported and will most likely display funky |
| things. |
| </div> |
| <![endif]--> |
| |
| |
| |
| <nav class="sidebar"> |
| |
| <p class='location'>Crate cfg_if</p><div class="block items"><ul><li><a href="#macros">Macros</a></li></ul></div><p class='location'></p><script>window.sidebarCurrent = {name: 'cfg_if', ty: 'mod', relpath: '../'};</script> |
| </nav> |
| |
| <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'>Crate <a class="mod" href=''>cfg_if</a></span><span class='out-of-band'><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/cfg_if/lib.rs.html#1-133' title='goto source code'>[src]</a></span></h1> |
| <div class='docblock'><p>A macro for defining #[cfg] if-else statements.</p> |
| |
| <p>The macro provided by this crate, <code>cfg_if</code>, is similar to the <code>if/elif</code> C |
| preprocessor macro by allowing definition of a cascade of <code>#[cfg]</code> cases, |
| emitting the implementation which matches first.</p> |
| |
| <p>This allows you to conveniently provide a long list #[cfg]'d blocks of code |
| without having to rewrite each clause multiple times.</p> |
| |
| <h1 id='example' class='section-header'><a href='#example'>Example</a></h1> |
| <pre class="rust rust-example-rendered"> |
| <span class="attribute">#[<span class="ident">macro_use</span>]</span> |
| <span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">cfg_if</span>; |
| |
| <span class="macro">cfg_if</span><span class="macro">!</span> { |
| <span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">unix</span>)]</span> { |
| <span class="kw">fn</span> <span class="ident">foo</span>() { <span class="comment">/* unix specific functionality */</span> } |
| } <span class="kw">else</span> <span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">target_pointer_width</span> <span class="op">=</span> <span class="string">"32"</span>)]</span> { |
| <span class="kw">fn</span> <span class="ident">foo</span>() { <span class="comment">/* non-unix, 32-bit functionality */</span> } |
| } <span class="kw">else</span> { |
| <span class="kw">fn</span> <span class="ident">foo</span>() { <span class="comment">/* fallback implementation */</span> } |
| } |
| } |
| </pre> |
| </div><h2 id='macros' class='section-header'><a href="#macros">Macros</a></h2> |
| <table> |
| <tr class=' module-item'> |
| <td><a class="macro" href="macro.cfg_if.html" |
| title='macro cfg_if::cfg_if'>cfg_if</a></td> |
| <td class='docblock-short'> |
| |
| </td> |
| </tr></table></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>?</dt> |
| <dd>Show this help dialog</dd> |
| <dt>S</dt> |
| <dd>Focus the search field</dd> |
| <dt>⇤</dt> |
| <dd>Move up in search results</dd> |
| <dt>⇥</dt> |
| <dd>Move down in search results</dd> |
| <dt>⏎</dt> |
| <dd>Go to active search result</dd> |
| <dt>+</dt> |
| <dd>Collapse/expand 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 = "cfg_if"; |
| </script> |
| <script src="../main.js"></script> |
| <script defer src="../search-index.js"></script> |
| </body> |
| </html> |
