41 lines
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41 lines
5.7 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="Given a mutable raw pointer to a type with an `s_type` member such as `vk::BaseOutStructure`, match on a set of Vulkan structures. The struct will be rebound to the given variable of the type of the given Vulkan structure."><title>match_out_struct in ash - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../static.files/rustdoc-42caa33d.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="ash" data-themes="" data-resource-suffix="" data-rustdoc-version="1.84.0 (9fc6b4312 2025-01-07)" data-channel="1.84.0" data-search-js="search-92e6798f.js" data-settings-js="settings-0f613d39.js" ><script src="../static.files/storage-59e33391.js"></script><script defer src="sidebar-items.js"></script><script defer src="../static.files/main-5f194d8c.js"></script><noscript><link rel="stylesheet" href="../static.files/noscript-893ab5e7.css"></noscript><link rel="alternate icon" type="image/png" href="../static.files/favicon-32x32-6580c154.png"><link rel="icon" type="image/svg+xml" href="../static.files/favicon-044be391.svg"></head><body class="rustdoc macro"><!--[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" title="show sidebar"></button></nav><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../ash/index.html">ash</a><span class="version">0.38.0+1.3.281</span></h2></div><div class="sidebar-elems"><div id="rustdoc-modnav"></div></div></nav><div class="sidebar-resizer"></div><main><div class="width-limiter"><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><span class="rustdoc-breadcrumbs"><a href="index.html">ash</a></span><h1>Macro <span class="macro">match_out_struct</span><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"><a class="src" href="../src/ash/lib.rs.html#140-153">Source</a> </span></div><pre class="rust item-decl"><code>macro_rules! match_out_struct {
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(match $p:ident { $($bind:ident @ $ty:path => $body:block $(,)?)+ $(_ => $any:block $(,)?)? }) => { ... };
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}</code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Given a mutable raw pointer to a type with an <code>s_type</code> member such as <a href="vk/struct.BaseOutStructure.html" title="struct ash::vk::BaseOutStructure"><code>vk::BaseOutStructure</code></a>,
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match on a set of Vulkan structures. The struct will be rebound to the given variable of the
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type of the given Vulkan structure.</p>
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<p>Note that all match bodies have to be enclosed by curly braces due to macro parsing limitations.
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It is unfortunately not possible to write <code>x @ ash::vk::SomeStruct => one_line_expression(),</code>.</p>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">let </span><span class="kw-2">mut </span>info = ash::vk::DeviceCreateInfo::default();
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<span class="kw">let </span>info: <span class="kw-2">*mut </span>ash::vk::BaseOutStructure = <<span class="kw-2">*mut </span><span class="kw">_</span>>::cast(<span class="kw-2">&mut </span>info);
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<span class="kw">unsafe </span>{
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<span class="macro">ash::match_out_struct!</span>(<span class="kw">match </span>info {
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info @ ash::vk::DeviceQueueCreateInfo => {
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<span class="macro">dbg!</span>(<span class="kw-2">&</span>info); <span class="comment">// Unreachable
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</span>}
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info @ ash::vk::DeviceCreateInfo => {
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<span class="macro">dbg!</span>(<span class="kw-2">&</span>info);
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}
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})
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}</code></pre></div>
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<p>In addition this macro propagates implicit return values just like normal <code>match</code> blocks, as
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long as a default value or expression is provided in the “any” match arm
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(<code>_ => { some_value() }</code>). For the time being said arm must be wrapped in curly braces; an
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expression like <code>_ => None</code> is not yet supported.</p>
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<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">let </span>device_create_flags: <span class="prelude-ty">Option</span><ash::vk::DeviceCreateFlags> = <span class="kw">unsafe </span>{
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<span class="macro">ash::match_out_struct!</span>(<span class="kw">match </span>info {
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info @ ash::vk::DeviceQueueCreateInfo => {
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<span class="macro">dbg!</span>(<span class="kw-2">&</span>info); <span class="comment">// Unreachable
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</span><span class="prelude-val">Some</span>(ash::vk::DeviceCreateFlags::empty())
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}
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info @ ash::vk::DeviceCreateInfo => {
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<span class="macro">dbg!</span>(<span class="kw-2">&</span>info);
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<span class="prelude-val">Some</span>(info.flags)
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}
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<span class="kw">_ </span>=> {
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<span class="prelude-val">None
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</span>}
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})
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};</code></pre></div>
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</div></details></section></div></main></body></html> |