| <!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="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/anyhow-1.0.71/src/macros.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>macros.rs - source</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="../../source-script.js"></script><script defer src="../../source-files.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 source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../anyhow/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../anyhow/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><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="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="doccomment">/// Return early with an error. |
| /// |
| /// This macro is equivalent to `return Err(`[`anyhow!($args...)`][anyhow!]`)`. |
| /// |
| /// The surrounding function's or closure's return value is required to be |
| /// `Result<_,`[`anyhow::Error`][crate::Error]`>`. |
| /// |
| /// [anyhow!]: crate::anyhow |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// # use anyhow::{bail, Result}; |
| /// # |
| /// # fn has_permission(user: usize, resource: usize) -> bool { |
| /// # true |
| /// # } |
| /// # |
| /// # fn main() -> Result<()> { |
| /// # let user = 0; |
| /// # let resource = 0; |
| /// # |
| /// if !has_permission(user, resource) { |
| /// bail!("permission denied for accessing {}", resource); |
| /// } |
| /// # Ok(()) |
| /// # } |
| /// ``` |
| /// |
| /// ``` |
| /// # use anyhow::{bail, Result}; |
| /// # use thiserror::Error; |
| /// # |
| /// # const MAX_DEPTH: usize = 1; |
| /// # |
| /// #[derive(Error, Debug)] |
| /// enum ScienceError { |
| /// #[error("recursion limit exceeded")] |
| /// RecursionLimitExceeded, |
| /// # #[error("...")] |
| /// # More = (stringify! { |
| /// ... |
| /// # }, 1).1, |
| /// } |
| /// |
| /// # fn main() -> Result<()> { |
| /// # let depth = 0; |
| /// # |
| /// if depth > MAX_DEPTH { |
| /// bail!(ScienceError::RecursionLimitExceeded); |
| /// } |
| /// # Ok(()) |
| /// # } |
| /// ``` |
| </span><span class="attribute">#[macro_export] |
| </span><span class="macro">macro_rules! </span>bail { |
| (<span class="macro-nonterminal">$msg</span>:literal $(,)<span class="question-mark">?</span>) => { |
| <span class="kw">return </span><span class="macro-nonterminal">$crate::__private::Err</span>(<span class="macro-nonterminal">$</span><span class="macro">crate::__anyhow!</span>(<span class="macro-nonterminal">$msg</span>)) |
| }; |
| (<span class="macro-nonterminal">$err</span>:expr $(,)<span class="question-mark">?</span>) => { |
| <span class="kw">return </span><span class="macro-nonterminal">$crate::__private::Err</span>(<span class="macro-nonterminal">$</span><span class="macro">crate::__anyhow!</span>(<span class="macro-nonterminal">$err</span>)) |
| }; |
| (<span class="macro-nonterminal">$fmt</span>:expr, $(<span class="macro-nonterminal">$arg</span>:tt)<span class="kw-2">*</span>) => { |
| <span class="kw">return </span><span class="macro-nonterminal">$crate::__private::Err</span>(<span class="macro-nonterminal">$</span><span class="macro">crate::__anyhow!</span>(<span class="macro-nonterminal">$fmt</span>, $(<span class="macro-nonterminal">$arg</span>)<span class="kw-2">*</span>)) |
| }; |
| } |
| |
| <span class="doccomment">/// Return early with an error if a condition is not satisfied. |
| /// |
| /// This macro is equivalent to `if !$cond { return |
| /// Err(`[`anyhow!($args...)`][anyhow!]`); }`. |
| /// |
| /// The surrounding function's or closure's return value is required to be |
| /// `Result<_,`[`anyhow::Error`][crate::Error]`>`. |
| /// |
| /// Analogously to `assert!`, `ensure!` takes a condition and exits the function |
| /// if the condition fails. Unlike `assert!`, `ensure!` returns an `Error` |
| /// rather than panicking. |
| /// |
| /// [anyhow!]: crate::anyhow |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// # use anyhow::{ensure, Result}; |
| /// # |
| /// # fn main() -> Result<()> { |
| /// # let user = 0; |
| /// # |
| /// ensure!(user == 0, "only user 0 is allowed"); |
| /// # Ok(()) |
| /// # } |
| /// ``` |
| /// |
| /// ``` |
| /// # use anyhow::{ensure, Result}; |
| /// # use thiserror::Error; |
| /// # |
| /// # const MAX_DEPTH: usize = 1; |
| /// # |
| /// #[derive(Error, Debug)] |
| /// enum ScienceError { |
| /// #[error("recursion limit exceeded")] |
| /// RecursionLimitExceeded, |
| /// # #[error("...")] |
| /// # More = (stringify! { |
| /// ... |
| /// # }, 1).1, |
| /// } |
| /// |
| /// # fn main() -> Result<()> { |
| /// # let depth = 0; |
| /// # |
| /// ensure!(depth <= MAX_DEPTH, ScienceError::RecursionLimitExceeded); |
| /// # Ok(()) |
| /// # } |
| /// ``` |
| </span><span class="attribute">#[cfg(doc)] |
| #[macro_export] |
| </span><span class="macro">macro_rules! </span>ensure { |
| (<span class="macro-nonterminal">$cond</span>:expr $(,)<span class="question-mark">?</span>) => { |
| <span class="kw">if </span>!<span class="macro-nonterminal">$cond </span>{ |
| <span class="kw">return </span><span class="macro-nonterminal">$crate::__private::Err</span>(<span class="macro-nonterminal">$crate::Error::msg</span>( |
| <span class="macro-nonterminal">$</span><span class="macro">crate::__private::concat!</span>(<span class="string">"Condition failed: `"</span>, <span class="macro-nonterminal">$</span><span class="macro">crate::__private::stringify!</span>(<span class="macro-nonterminal">$cond</span>), <span class="string">"`"</span>) |
| )); |
| } |
| }; |
| (<span class="macro-nonterminal">$cond</span>:expr, <span class="macro-nonterminal">$msg</span>:literal $(,)<span class="question-mark">?</span>) => { |
| <span class="kw">if </span>!<span class="macro-nonterminal">$cond </span>{ |
| <span class="kw">return </span><span class="macro-nonterminal">$crate::__private::Err</span>(<span class="macro-nonterminal">$</span><span class="macro">crate::__anyhow!</span>(<span class="macro-nonterminal">$msg</span>)); |
| } |
| }; |
| (<span class="macro-nonterminal">$cond</span>:expr, <span class="macro-nonterminal">$err</span>:expr $(,)<span class="question-mark">?</span>) => { |
| <span class="kw">if </span>!<span class="macro-nonterminal">$cond </span>{ |
| <span class="kw">return </span><span class="macro-nonterminal">$crate::__private::Err</span>(<span class="macro-nonterminal">$</span><span class="macro">crate::__anyhow!</span>(<span class="macro-nonterminal">$err</span>)); |
| } |
| }; |
| (<span class="macro-nonterminal">$cond</span>:expr, <span class="macro-nonterminal">$fmt</span>:expr, $(<span class="macro-nonterminal">$arg</span>:tt)<span class="kw-2">*</span>) => { |
| <span class="kw">if </span>!<span class="macro-nonterminal">$cond </span>{ |
| <span class="kw">return </span><span class="macro-nonterminal">$crate::__private::Err</span>(<span class="macro-nonterminal">$</span><span class="macro">crate::__anyhow!</span>(<span class="macro-nonterminal">$fmt</span>, $(<span class="macro-nonterminal">$arg</span>)<span class="kw-2">*</span>)); |
| } |
| }; |
| } |
| |
| <span class="attribute">#[cfg(not(doc))] |
| #[macro_export] |
| </span><span class="macro">macro_rules! </span>ensure { |
| ($(<span class="macro-nonterminal">$tt</span>:tt)<span class="kw-2">*</span>) => { |
| <span class="macro-nonterminal">$</span><span class="macro">crate::__parse_ensure!</span>( |
| <span class="comment">/* state */ </span><span class="number">0 |
| </span><span class="comment">/* stack */ </span>() |
| <span class="comment">/* bail */ </span>($(<span class="macro-nonterminal">$tt</span>)<span class="kw-2">*</span>) |
| <span class="comment">/* fuel */ </span>(~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~~~~) |
| <span class="comment">/* parse */ </span>{()} |
| <span class="comment">/* dup */ </span>($(<span class="macro-nonterminal">$tt</span>)<span class="kw-2">*</span>) |
| <span class="comment">/* rest */ </span>$(<span class="macro-nonterminal">$tt</span>)* |
| ) |
| }; |
| } |
| |
| <span class="doccomment">/// Construct an ad-hoc error from a string or existing non-`anyhow` error |
| /// value. |
| /// |
| /// This evaluates to an [`Error`][crate::Error]. It can take either just a |
| /// string, or a format string with arguments. It also can take any custom type |
| /// which implements `Debug` and `Display`. |
| /// |
| /// If called with a single argument whose type implements `std::error::Error` |
| /// (in addition to `Debug` and `Display`, which are always required), then that |
| /// Error impl's `source` is preserved as the `source` of the resulting |
| /// `anyhow::Error`. |
| /// |
| /// # Example |
| /// |
| /// ``` |
| /// # type V = (); |
| /// # |
| /// use anyhow::{anyhow, Result}; |
| /// |
| /// fn lookup(key: &str) -> Result<V> { |
| /// if key.len() != 16 { |
| /// return Err(anyhow!("key length must be 16 characters, got {:?}", key)); |
| /// } |
| /// |
| /// // ... |
| /// # Ok(()) |
| /// } |
| /// ``` |
| </span><span class="attribute">#[macro_export] |
| </span><span class="macro">macro_rules! </span>anyhow { |
| (<span class="macro-nonterminal">$msg</span>:literal $(,)<span class="question-mark">?</span>) => { |
| <span class="macro-nonterminal">$crate::__private::must_use</span>({ |
| <span class="kw">let </span>error = <span class="macro-nonterminal">$crate::__private::format_err</span>(<span class="macro-nonterminal">$</span><span class="macro">crate::__private::format_args!</span>(<span class="macro-nonterminal">$msg</span>)); |
| error |
| }) |
| }; |
| (<span class="macro-nonterminal">$err</span>:expr $(,)<span class="question-mark">?</span>) => { |
| <span class="macro-nonterminal">$crate::__private::must_use</span>({ |
| <span class="kw">use </span><span class="macro-nonterminal">$crate::__private::kind</span>::<span class="kw-2">*</span>; |
| <span class="kw">let </span>error = <span class="kw">match </span><span class="macro-nonterminal">$err </span>{ |
| error => (<span class="kw-2">&</span>error).anyhow_kind().new(error), |
| }; |
| error |
| }) |
| }; |
| (<span class="macro-nonterminal">$fmt</span>:expr, $(<span class="macro-nonterminal">$arg</span>:tt)<span class="kw-2">*</span>) => { |
| <span class="macro-nonterminal">$crate::Error::msg</span>(<span class="macro-nonterminal">$</span><span class="macro">crate::__private::format!</span>(<span class="macro-nonterminal">$fmt</span>, $(<span class="macro-nonterminal">$arg</span>)<span class="kw-2">*</span>)) |
| }; |
| } |
| |
| <span class="comment">// Not public API. This is used in the implementation of some of the other |
| // macros, in which the must_use call is not needed because the value is known |
| // to be used. |
| </span><span class="attribute">#[doc(hidden)] |
| #[macro_export] |
| </span><span class="macro">macro_rules! </span>__anyhow { |
| (<span class="macro-nonterminal">$msg</span>:literal $(,)<span class="question-mark">?</span>) => ({ |
| <span class="kw">let </span>error = <span class="macro-nonterminal">$crate::__private::format_err</span>(<span class="macro-nonterminal">$</span><span class="macro">crate::__private::format_args!</span>(<span class="macro-nonterminal">$msg</span>)); |
| error |
| }); |
| (<span class="macro-nonterminal">$err</span>:expr $(,)<span class="question-mark">?</span>) => ({ |
| <span class="kw">use </span><span class="macro-nonterminal">$crate::__private::kind</span>::<span class="kw-2">*</span>; |
| <span class="kw">let </span>error = <span class="kw">match </span><span class="macro-nonterminal">$err </span>{ |
| error => (<span class="kw-2">&</span>error).anyhow_kind().new(error), |
| }; |
| error |
| }); |
| (<span class="macro-nonterminal">$fmt</span>:expr, $(<span class="macro-nonterminal">$arg</span>:tt)<span class="kw-2">*</span>) => { |
| <span class="macro-nonterminal">$crate::Error::msg</span>(<span class="macro-nonterminal">$</span><span class="macro">crate::__private::format!</span>(<span class="macro-nonterminal">$fmt</span>, $(<span class="macro-nonterminal">$arg</span>)<span class="kw-2">*</span>)) |
| }; |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="anyhow" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
