156 lines
6.5 KiB
HTML
156 lines
6.5 KiB
HTML
|
<!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" 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>
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
</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">
|
|||
|
|
<div class="sidebar-menu">☰</div>
|
|||
|
|
|
|||
|
|
<p class='location'>Crate cfg_if</p><div class="sidebar-elems"><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></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">
|
|||
|
|
</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#1-142' title='goto source code'>[src]</a></span></h1>
|
|||
|
|
<div class='docblock'><p>A macro for defining <code>#[cfg]</code> 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 <code>#[cfg]</code>'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><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 = "cfg_if";
|
|||
|
|
</script>
|
|||
|
|
<script src="../main.js"></script>
|
|||
|
|
<script defer src="../search-index.js"></script>
|
|||
|
|
</body>
|
|||
|
|
</html>
|