42 lines
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42 lines
7.3 KiB
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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 `set_logger` fn in crate `log`."><meta name="keywords" content="rust, rustlang, rust-lang, set_logger"><title>log::set_logger - 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="../light.css" id="themeStyle"><link rel="stylesheet" type="text/css" href="../dark.css" disabled ><link rel="stylesheet" type="text/css" href="../ayu.css" disabled ><script id="default-settings"></script><script src="../storage.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="shortcut icon" href="https://www.rust-lang.org/favicon.ico"><style type="text/css">#crate-search{background-image:url("../down-arrow.svg");}</style></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='../log/index.html'><div class='logo-container'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo'></div></a><div class="sidebar-elems"><p class="location"><a href="index.html">log</a></p><script>window.sidebarCurrent = {name: "set_logger", ty: "fn", relpath: ""};</script><script defer src="sidebar-items.js"></script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!" aria-haspopup="menu"><img src="../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices" role="menu"></div></div><script src="../theme.js"></script><nav class="sub"><form class="search-form"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" disabled autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><span class="help-button">?</span>
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<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/log/lib.rs.html#1260-1262" title="goto source code">[src]</a></span><span class="in-band">Function <a href="index.html">log</a>::<wbr><a class="fn" href="">set_logger</a></span></h1><pre class="rust fn">pub fn set_logger(logger: &'static dyn <a class="trait" href="../log/trait.Log.html" title="trait log::Log">Log</a>) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><(), <a class="struct" href="../log/struct.SetLoggerError.html" title="struct log::SetLoggerError">SetLoggerError</a>></pre><div class="docblock"><p>Sets the global logger to a <code>&'static Log</code>.</p>
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<p>This function may only be called once in the lifetime of a program. Any log
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events that occur before the call to <code>set_logger</code> completes will be ignored.</p>
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<p>This function does not typically need to be called manually. Logger
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implementations should provide an initialization method that installs the
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logger internally.</p>
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<h1 id="availability" class="section-header"><a href="#availability">Availability</a></h1>
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<p>This method is available even when the <code>std</code> feature is disabled. However,
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it is currently unavailable on <code>thumbv6</code> targets, which lack support for
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some atomic operations which are used by this function. Even on those
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targets, <a href="fn.set_logger_racy.html"><code>set_logger_racy</code></a> will be available.</p>
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<h1 id="errors" class="section-header"><a href="#errors">Errors</a></h1>
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<p>An error is returned if a logger has already been set.</p>
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<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
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<div class='information'><div class='tooltip edition'>ⓘ<span class='tooltiptext'>This code runs with edition 2018</span></div></div><div class="example-wrap"><pre class="rust rust-example-rendered edition ">
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<span class="kw">use</span> <span class="ident">log</span>::{<span class="ident">error</span>, <span class="ident">info</span>, <span class="ident">warn</span>, <span class="ident">Record</span>, <span class="ident">Level</span>, <span class="ident">Metadata</span>, <span class="ident">LevelFilter</span>};
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<span class="kw">static</span> <span class="ident">MY_LOGGER</span>: <span class="ident">MyLogger</span> <span class="op">=</span> <span class="ident">MyLogger</span>;
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<span class="kw">struct</span> <span class="ident">MyLogger</span>;
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<span class="kw">impl</span> <span class="ident">log</span>::<span class="ident">Log</span> <span class="kw">for</span> <span class="ident">MyLogger</span> {
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<span class="kw">fn</span> <span class="ident">enabled</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">metadata</span>: <span class="kw-2">&</span><span class="ident">Metadata</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
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<span class="ident">metadata</span>.<span class="ident">level</span>() <span class="op"><</span><span class="op">=</span> <span class="ident">Level</span>::<span class="ident">Info</span>
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}
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<span class="kw">fn</span> <span class="ident">log</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">record</span>: <span class="kw-2">&</span><span class="ident">Record</span>) {
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<span class="kw">if</span> <span class="self">self</span>.<span class="ident">enabled</span>(<span class="ident">record</span>.<span class="ident">metadata</span>()) {
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<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{} - {}"</span>, <span class="ident">record</span>.<span class="ident">level</span>(), <span class="ident">record</span>.<span class="ident">args</span>());
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}
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}
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<span class="kw">fn</span> <span class="ident">flush</span>(<span class="kw-2">&</span><span class="self">self</span>) {}
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}
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<span class="ident">log</span>::<span class="ident">set_logger</span>(<span class="kw-2">&</span><span class="ident">MY_LOGGER</span>).<span class="ident">unwrap</span>();
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<span class="ident">log</span>::<span class="ident">set_max_level</span>(<span class="ident">LevelFilter</span>::<span class="ident">Info</span>);
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<span class="macro">info</span><span class="macro">!</span>(<span class="string">"hello log"</span>);
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<span class="macro">warn</span><span class="macro">!</span>(<span class="string">"warning"</span>);
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<span class="macro">error</span><span class="macro">!</span>(<span class="string">"oops"</span>);</pre></div>
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