| <!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="Sets the global logger to a `&'static Log`."><meta name="keywords" content="rust, rustlang, rust-lang, set_logger"><title>set_logger in log - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../normalize.css"><link rel="stylesheet" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../ayu.css" disabled><link rel="stylesheet" href="../dark.css" disabled><link rel="stylesheet" href="../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../storage.js"></script><script defer src="sidebar-items.js"></script><script defer src="../main.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="icon" href="https://www.rust-lang.org/favicon.ico"></head><body class="rustdoc fn"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">☰</button><a class="sidebar-logo" 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><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" 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"><h2><a href="index.html">In log</a></h2></div></nav><main><div class="width-limiter"><nav class="sub"><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1 class="fqn">Function <a href="index.html">log</a>::<wbr><a class="fn" href="#">set_logger</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../src/log/lib.rs.html#1347-1349">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="item-decl"><pre class="rust fn"><code>pub fn set_logger(logger: &'static dyn <a class="trait" href="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="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.unit.html">()</a>, <a class="struct" href="struct.SetLoggerError.html" title="struct log::SetLoggerError">SetLoggerError</a>></code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Sets the global logger to a <code>&'static Log</code>.</p> |
| <p>This function may only be called once in the lifetime of a program. Any log |
| events that occur before the call to <code>set_logger</code> completes will be ignored.</p> |
| <p>This function does not typically need to be called manually. Logger |
| implementations should provide an initialization method that installs the |
| logger internally.</p> |
| <h2 id="availability"><a href="#availability">Availability</a></h2> |
| <p>This method is available even when the <code>std</code> feature is disabled. However, |
| it is currently unavailable on <code>thumbv6</code> targets, which lack support for |
| some atomic operations which are used by this function. Even on those |
| targets, <a href="fn.set_logger_racy.html"><code>set_logger_racy</code></a> will be available.</p> |
| <h2 id="errors"><a href="#errors">Errors</a></h2> |
| <p>An error is returned if a logger has already been set.</p> |
| <h2 id="examples"><a href="#examples">Examples</a></h2> |
| <div class="example-wrap edition"><div class='tooltip' data-edition="2018">ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">use </span>log::{error, info, warn, Record, Level, Metadata, LevelFilter}; |
| |
| <span class="kw">static </span>MY_LOGGER: MyLogger = MyLogger; |
| |
| <span class="kw">struct </span>MyLogger; |
| |
| <span class="kw">impl </span>log::Log <span class="kw">for </span>MyLogger { |
| <span class="kw">fn </span>enabled(<span class="kw-2">&</span><span class="self">self</span>, metadata: <span class="kw-2">&</span>Metadata) -> bool { |
| metadata.level() <= Level::Info |
| } |
| |
| <span class="kw">fn </span>log(<span class="kw-2">&</span><span class="self">self</span>, record: <span class="kw-2">&</span>Record) { |
| <span class="kw">if </span><span class="self">self</span>.enabled(record.metadata()) { |
| <span class="macro">println!</span>(<span class="string">"{} - {}"</span>, record.level(), record.args()); |
| } |
| } |
| <span class="kw">fn </span>flush(<span class="kw-2">&</span><span class="self">self</span>) {} |
| } |
| |
| log::set_logger(<span class="kw-2">&</span>MY_LOGGER).unwrap(); |
| log::set_max_level(LevelFilter::Info); |
| |
| <span class="macro">info!</span>(<span class="string">"hello log"</span>); |
| <span class="macro">warn!</span>(<span class="string">"warning"</span>); |
| <span class="macro">error!</span>(<span class="string">"oops"</span>);</code></pre></div> |
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