github-actions[bot]
40 lines
7.0 KiB
HTML
40 lines
7.0 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="API documentation for the Rust `unsafe_pinned` macro in crate `pin_utils`."><meta name="keywords" content="rust, rustlang, rust-lang, unsafe_pinned"><title>pin_utils::unsafe_pinned - 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="icon" type="image/svg+xml" href="../favicon.svg">
|
||
<link rel="alternate icon" type="image/png" href="../favicon-16x16.png">
|
||
<link rel="alternate icon" type="image/png" href="../favicon-32x32.png"><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='../pin_utils/index.html'><div class='logo-container rust-logo'><img src='../rust-logo.png' alt='logo'></div></a><div class="sidebar-elems"><p class="location"><a href="index.html">pin_utils</a></p><div id="sidebar-vars" data-name="unsafe_pinned" data-ty="macro" data-relpath=""></div><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><button type="button" class="help-button">?</button>
|
||
<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="in-band">Macro <a href="index.html">pin_utils</a>::<wbr><a class="macro" href="">unsafe_pinned</a></span><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/pin_utils/projection.rs.html#40-53" title="goto source code">[src]</a></span></h1><div class="docblock type-decl hidden-by-usual-hider"><div class="example-wrap"><pre class="rust macro">
|
||
<span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">unsafe_pinned</span> {
|
||
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">f</span>:<span class="ident">tt</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">t</span>:<span class="ident">ty</span>) <span class="op">=</span><span class="op">></span> { ... };
|
||
}</pre></div>
|
||
</div><div class="docblock"><p>A pinned projection of a struct field.</p>
|
||
<h1 id="safety" class="section-header"><a href="#safety">Safety</a></h1>
|
||
<p>To make using this macro safe, three things need to be ensured:</p>
|
||
<ul>
|
||
<li>If the struct implements <a href="https://doc.rust-lang.org/nightly/core/ops/drop/trait.Drop.html#tymethod.drop"><code>Drop</code></a>, the <a href="https://doc.rust-lang.org/nightly/core/ops/drop/trait.Drop.html#tymethod.drop"><code>drop</code></a> method is not allowed to
|
||
move the value of the field.</li>
|
||
<li>If the struct wants to implement <a href="https://doc.rust-lang.org/nightly/core/marker/trait.Unpin.html"><code>Unpin</code></a>, it has to do so conditionally:
|
||
The struct can only implement <a href="https://doc.rust-lang.org/nightly/core/marker/trait.Unpin.html"><code>Unpin</code></a> if the field's type is <a href="https://doc.rust-lang.org/nightly/core/marker/trait.Unpin.html"><code>Unpin</code></a>.</li>
|
||
<li>The struct must not be <code>#[repr(packed)]</code>.</li>
|
||
</ul>
|
||
<h1 id="example" class="section-header"><a href="#example">Example</a></h1>
|
||
<div class="example-wrap"><pre class="rust rust-example-rendered">
|
||
<span class="kw">use</span> <span class="ident">pin_utils</span>::<span class="ident">unsafe_pinned</span>;
|
||
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">marker</span>::<span class="ident">Unpin</span>;
|
||
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">pin</span>::<span class="ident">Pin</span>;
|
||
|
||
<span class="kw">struct</span> <span class="ident">Foo</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
|
||
<span class="ident">field</span>: <span class="ident">T</span>,
|
||
}
|
||
|
||
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Foo</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
|
||
<span class="macro">unsafe_pinned</span><span class="macro">!</span>(<span class="ident">field</span>: <span class="ident">T</span>);
|
||
|
||
<span class="kw">fn</span> <span class="ident">baz</span>(<span class="kw-2">mut</span> <span class="self">self</span>: <span class="ident">Pin</span><span class="op"><</span><span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">Self</span><span class="op">></span>) {
|
||
<span class="kw">let</span> <span class="kw">_</span>: <span class="ident">Pin</span><span class="op"><</span><span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">T</span><span class="op">></span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">field</span>(); <span class="comment">// Pinned reference to the field</span>
|
||
}
|
||
}
|
||
|
||
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Unpin</span><span class="op">></span> <span class="ident">Unpin</span> <span class="kw">for</span> <span class="ident">Foo</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {} <span class="comment">// Conditional Unpin impl</span></pre></div>
|
||
<p>Note: borrowing the field multiple times requires using <code>.as_mut()</code> to
|
||
avoid consuming the <code>Pin</code>.</p>
|
||
</div></section><section id="search" class="content hidden"></section><section class="footer"></section><div id="rustdoc-vars" data-root-path="../" data-current-crate="pin_utils"></div>
|
||
<script src="../main.js"></script><script defer src="../search-index.js"></script></body></html> |