<!DOCTYPE html><htmllang="en"><head><metacharset="utf-8"><metaname="viewport"content="width=device-width, initial-scale=1.0"><metaname="generator"content="rustdoc"><metaname="description"content="Construct an ad-hoc error from a string or existing non-`anyhow` error value."><title>anyhow in anyhow - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-46f98efaafac5295.ttf.woff2,FiraSans-Regular-018c141bf0843ffd.woff2,FiraSans-Medium-8f9a781e4970d388.woff2,SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2,SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/${f}">`).join(""))</script><linkrel="stylesheet"href="../static.files/normalize-76eba96aa4d2e634.css"><linkrel="stylesheet"href="../static.files/rustdoc-dd39b87e5fcfba68.css"><metaname="rustdoc-vars"data-root-path="../"data-static-root-path="../static.files/"data-current-crate="anyhow"data-themes=""data-resource-suffix=""data-rustdoc-version="1.80.0 (051478957 2024-07-21)"data-channel="1.80.0"data-search-js="search-d52510db62a78183.js"data-settings-js="settings-4313503d2e1961c2.js"><scriptsrc="../static.files/storage-118b08c4c78b968e.js"></script><scriptdefersrc="sidebar-items.js"></script><scriptdefersrc="../static.files/main-20a3ad099b048cf2.js"></script><noscript><linkrel="stylesheet"href="../static.files/noscript-df360f571f6edeae.css"></noscript><linkrel="alternate icon"type="image/png"href="../static.files/favicon-32x32-422f7d1d52889060.png"><linkrel="icon"type="image/svg+xml"href="../static.files/favicon-2c020d218678b618.svg"></head><bodyclass="rustdoc macro"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><navclass="mobile-topbar"><buttonclass="sidebar-menu-toggle"title="show sidebar"></button></nav><navclass="sidebar"><divclass="sidebar-crate"><h2><ahref="../anyhow/index.html">anyhow</a><spanclass="version">1.0.86</span></h2></div><divclass="sidebar-elems"></div></nav><divclass="sidebar-resizer"></div><main><divclass="width-limiter"><rustdoc-search></rustdoc-search><sectionid="main-content"class="content"><divclass="main-heading"><h1>Macro <ahref="index.html">anyhow</a>::<wbr><aclass="macro"href="#">anyhow</a><buttonid="copy-path"title="Copy item path to clipboard">Copy item path</button></h1><spanclass="out-of-band"><aclass="src"href="../src/anyhow/macros.rs.html#200-219">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><preclass="rust item-decl"><spanclass="macro">macro_rules!</span> anyhow {
}</pre><detailsclass="toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>Construct an ad-hoc error from a string or existing non-<code>anyhow</code> error
value.</p>
<p>This evaluates to an <ahref="struct.Error.html"title="struct anyhow::Error"><code>Error</code></a>. It can take either just a
string, or a format string with arguments. It also can take any custom type
which implements <code>Debug</code> and <code>Display</code>.</p>
<p>If called with a single argument whose type implements <code>std::error::Error</code>
(in addition to <code>Debug</code> and <code>Display</code>, which are always required), then that
Error impl’s <code>source</code> is preserved as the <code>source</code> of the resulting
<spanclass="kw">return </span><spanclass="prelude-val">Err</span>(<spanclass="macro">anyhow!</span>(<spanclass="string">"key length must be 16 characters, got {:?}"</span>, key));
