| <!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 f32 to the given buffer and return number of bytes written."><meta name="keywords" content="rust, rustlang, rust-lang, format32"><title>format32 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" 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="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></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><a href="index.html">In ryu::raw</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">ryu</a>::<wbr><a href="index.html">raw</a>::<wbr><a class="fn" href="#">format32</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/ryu/pretty/mod.rs.html#159-224">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 unsafe fn format32(f: f32, result: *mut u8) -> usize</code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Print f32 to the given buffer and return number of bytes written.</p> |
| <p>At most 16 bytes will be written.</p> |
| <h3 id="special-cases"><a href="#special-cases">Special cases</a></h3> |
| <p>This function <strong>does not</strong> check for NaN or infinity. If the input |
| number is not a finite float, the printed representation will be some |
| correctly formatted but unspecified numerical value.</p> |
| <p>Please check <a href="https://doc.rust-lang.org/std/primitive.f32.html#method.is_finite"><code>is_finite</code></a> yourself before calling this function, or |
| check <a href="https://doc.rust-lang.org/std/primitive.f32.html#method.is_nan"><code>is_nan</code></a> and <a href="https://doc.rust-lang.org/std/primitive.f32.html#method.is_infinite"><code>is_infinite</code></a> and handle those cases yourself.</p> |
| <h3 id="safety"><a href="#safety">Safety</a></h3> |
| <p>The <code>result</code> pointer argument must point to sufficiently many writable bytes |
| to hold Ryū’s representation of <code>f</code>.</p> |
| <h3 id="example"><a href="#example">Example</a></h3> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>std::{mem::MaybeUninit, slice, str}; |
| |
| <span class="kw">let </span>f = <span class="number">1.234f32</span>; |
| |
| <span class="kw">unsafe </span>{ |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer = [MaybeUninit::<u8>::uninit(); <span class="number">16</span>]; |
| <span class="kw">let </span>len = ryu::raw::format32(f, buffer.as_mut_ptr() <span class="kw">as </span><span class="kw-2">*mut </span>u8); |
| <span class="kw">let </span>slice = slice::from_raw_parts(buffer.as_ptr() <span class="kw">as </span><span class="kw-2">*const </span>u8, len); |
| <span class="kw">let </span>print = str::from_utf8_unchecked(slice); |
| <span class="macro">assert_eq!</span>(print, <span class="string">"1.234"</span>); |
| }</code></pre></div> |
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