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<!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` macro in crate `cfg_if`."><meta name="keywords" content="rust, rustlang, rust-lang, cfg_if"><title>cfg_if::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="../light.css" id="themeStyle"><script src="../storage.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="shortcut icon" href="../favicon.ico"><style type="text/css">#crate-search{background-image:url("../down-arrow.svg");}</style></head><body class="rustdoc macro"><!--[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='../cfg_if/index.html'><div class='logo-container'><img src='../rust-logo.png' alt='logo'></div></a><div class="sidebar-elems"><p class='location'><a href='index.html'>cfg_if</a></p><script>window.sidebarCurrent = {name: 'cfg_if', ty: 'macro', 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"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><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='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#38-90' title='goto source code'>[src]</a></span><span class='in-band'>Macro <a href='index.html'>cfg_if</a>::<wbr><a class="macro" href=''>cfg_if</a></span></h1><div class="docblock type-decl hidden-by-usual-hider"><div class="example-wrap"><pre class="rust macro">
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<span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">cfg_if</span> {
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($(
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<span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">meta</span>:<span class="ident">meta</span>),<span class="kw-2">*</span>)]</span> { $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">it</span>:<span class="ident">item</span>)<span class="op">*</span> }
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) <span class="kw">else</span> <span class="op">*</span> <span class="kw">else</span> {
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$(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">it2</span>:<span class="ident">item</span>)<span class="op">*</span>
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}) <span class="op">=</span><span class="op">></span> { ... };
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(
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<span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i_met</span>:<span class="ident">meta</span>),<span class="kw-2">*</span>)]</span> { $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i_it</span>:<span class="ident">item</span>)<span class="op">*</span> }
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$(
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<span class="kw">else</span> <span class="kw">if</span> <span class="attribute">#[<span class="ident">cfg</span>($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">e_met</span>:<span class="ident">meta</span>),<span class="kw-2">*</span>)]</span> { $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">e_it</span>:<span class="ident">item</span>)<span class="op">*</span> }
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)<span class="op">*</span>
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) <span class="op">=</span><span class="op">></span> { ... };
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(@<span class="ident">__items</span> ($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">not</span>:<span class="ident">meta</span>,)<span class="kw-2">*</span>) ; ) <span class="op">=</span><span class="op">></span> { ... };
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(@<span class="ident">__items</span> ($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">not</span>:<span class="ident">meta</span>,)<span class="kw-2">*</span>) ; ( ($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">m</span>:<span class="ident">meta</span>),<span class="kw-2">*</span>) ($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">it</span>:<span class="ident">item</span>)<span class="kw-2">*</span>) ), $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">rest</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
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(@<span class="ident">__apply</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">m</span>:<span class="ident">meta</span>, $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">it</span>:<span class="ident">item</span>)<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> { ... };
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}</pre></div>
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</div><div class='docblock'><p>The main macro provided by this crate. See crate documentation for more
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information.</p>
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