24 lines
7.3 KiB
HTML
24 lines
7.3 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="Print f64 to the given buffer and return number of bytes written."><meta name="keywords" content="rust, rustlang, rust-lang, format64"><title>format64 in ryu::raw - 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" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../ayu.css" disabled><link rel="stylesheet" type="text/css" href="../../dark.css" disabled><link rel="stylesheet" type="text/css" 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="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></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="../../ryu/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2 class="location"></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../../ryu/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><div class="sidebar-elems"><h2 class="location"><a href="index.html">In ryu::raw</a></h2></div></nav><main><div class="width-limiter"><div class="sub-container"><a class="sub-logo-container" href="../../ryu/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><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"><button type="button">?</button></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></div><section id="main-content" class="content"><div class="main-heading"><h1 class="fqn"><span class="in-band">Function <a href="../index.html">ryu</a>::<wbr><a href="index.html">raw</a>::<wbr><a class="fn" href="#">format64</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></span></h1><span class="out-of-band"><a class="srclink" href="../../src/ryu/pretty/mod.rs.html#52-118">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="docblock item-decl"><pre class="rust fn"><code>pub unsafe fn format64(f: <a class="primitive" href="https://doc.rust-lang.org/1.64.0/core/primitive.f64.html">f64</a>, result: <a class="primitive" href="https://doc.rust-lang.org/1.64.0/core/primitive.pointer.html">*mut </a><a class="primitive" href="https://doc.rust-lang.org/1.64.0/core/primitive.u8.html">u8</a>) -> <a class="primitive" href="https://doc.rust-lang.org/1.64.0/core/primitive.usize.html">usize</a></code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Print f64 to the given buffer and return number of bytes written.</p>
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<p>At most 24 bytes will be written.</p>
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<h3 id="special-cases"><a href="#special-cases">Special cases</a></h3>
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<p>This function <strong>does not</strong> check for NaN or infinity. If the input
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number is not a finite float, the printed representation will be some
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correctly formatted but unspecified numerical value.</p>
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<p>Please check <a href="https://doc.rust-lang.org/std/primitive.f64.html#method.is_finite"><code>is_finite</code></a> yourself before calling this function, or
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check <a href="https://doc.rust-lang.org/std/primitive.f64.html#method.is_nan"><code>is_nan</code></a> and <a href="https://doc.rust-lang.org/std/primitive.f64.html#method.is_infinite"><code>is_infinite</code></a> and handle those cases yourself.</p>
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<h3 id="safety"><a href="#safety">Safety</a></h3>
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<p>The <code>result</code> pointer argument must point to sufficiently many writable bytes
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to hold Ryū’s representation of <code>f</code>.</p>
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<h3 id="example"><a href="#example">Example</a></h3>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use</span> <span class="ident">std</span>::{<span class="ident">mem::MaybeUninit</span>, <span class="ident">slice</span>, <span class="ident">str</span>};
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<span class="kw">let</span> <span class="ident">f</span> <span class="op">=</span> <span class="number">1.234f64</span>;
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<span class="kw">unsafe</span> {
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<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buffer</span> <span class="op">=</span> [<span class="ident">MaybeUninit</span>::<span class="op"><</span><span class="ident">u8</span><span class="op">></span><span class="ident">::uninit</span>(); <span class="number">24</span>];
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<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">ryu::raw::format64</span>(<span class="ident">f</span>, <span class="ident">buffer</span>.<span class="ident">as_mut_ptr</span>() <span class="kw">as</span> <span class="kw-2">*mut</span> <span class="ident">u8</span>);
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<span class="kw">let</span> <span class="ident">slice</span> <span class="op">=</span> <span class="ident">slice::from_raw_parts</span>(<span class="ident">buffer</span>.<span class="ident">as_ptr</span>() <span class="kw">as</span> <span class="kw-2">*const</span> <span class="ident">u8</span>, <span class="ident">len</span>);
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<span class="kw">let</span> <span class="ident">print</span> <span class="op">=</span> <span class="ident">str::from_utf8_unchecked</span>(<span class="ident">slice</span>);
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<span class="macro">assert_eq!</span>(<span class="ident">print</span>, <span class="string">"1.234"</span>);
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}</code></pre></div>
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