| <!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/signal-hook-0.1.17/src/lib.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>lib.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="../../signal_hook/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="../../signal_hook/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="attribute">#![doc( |
| test(attr(deny(warnings))), |
| test(attr(allow(bare_trait_objects, unknown_lints))) |
| )] |
| #![allow( |
| unknown_lints, |
| renamed_and_removed_lints, |
| intra_doc_link_resolution_failure, |
| broken_itra_doc_links |
| )] |
| </span><span class="doccomment">//! Library for easier and safe Unix signal handling |
| //! |
| //! Unix signals are inherently hard to handle correctly, for several reasons: |
| //! |
| //! * They are a global resource. If a library wants to set its own signal handlers, it risks |
| //! disturbing some other library. It is possible to chain the previous signal handler, but then |
| //! it is impossible to remove the old signal handlers from the chains in any practical manner. |
| //! * They can be called from whatever thread, requiring synchronization. Also, as they can |
| //! interrupt a thread at any time, making most handling race-prone. |
| //! * According to the POSIX standard, the set of functions one may call inside a signal handler is |
| //! limited to very few of them. To highlight, mutexes (or other locking mechanisms) and memory |
| //! allocation and deallocation is *not* allowed. |
| //! |
| //! This library aims to solve some of the problems. It provides a global registry of actions |
| //! performed on arrival of signals. It is possible to register multiple actions for the same |
| //! signal and it is possible to remove the actions later on. If there was a previous signal |
| //! handler when the first action for a signal is registered, it is chained (but the original one |
| //! can't be removed). |
| //! |
| //! The main function of the library is [`register`](fn.register.html). |
| //! |
| //! It also offers several common actions one might want to register, implemented in the correct |
| //! way. They are scattered through submodules and have the same limitations and characteristics as |
| //! the [`register`](fn.register.html) function. Generally, they work to postpone the action taken |
| //! outside of the signal handler, where the full freedom and power of rust is available. |
| //! |
| //! Unlike other Rust libraries for signal handling, this should be flexible enough to handle all |
| //! the common and useful patterns. |
| //! |
| //! The library avoids all the newer fancy signal-handling routines. These generally have two |
| //! downsides: |
| //! |
| //! * They are not fully portable, therefore the library would have to contain *both* the |
| //! implementation using the basic routines and the fancy ones. As signal handling is not on the |
| //! hot path of most programs, this would not bring any actual benefit. |
| //! * The other routines require that the given signal is masked in all application's threads. As |
| //! the signals are not masked by default and a new thread inherits the signal mask of its |
| //! parent, it is possible to guarantee such global mask by masking them before any threads |
| //! start. While this is possible for an application developer to do, it is not possible for a |
| //! a library. |
| //! |
| //! # Warning |
| //! |
| //! Even with this library, you should thread with care. It does not eliminate all the problems |
| //! mentioned above. |
| //! |
| //! Also, note that the OS may collate multiple instances of the same signal into just one call of |
| //! the signal handler. Furthermore, some abstractions implemented here also naturally collate |
| //! multiple instances of the same signal. The general guarantee is, if there was at least one |
| //! signal of the given number delivered, an action will be taken, but it is not specified how many |
| //! times ‒ signals work mostly as kind of „wake up now“ nudge, if the application is slow to wake |
| //! up, it may be nudged multiple times before it does so. |
| //! |
| //! # Signal limitations |
| //! |
| //! OS limits still apply ‒ it is not possible to redefine certain signals (eg. `SIGKILL` or |
| //! `SIGSTOP`) and it is probably a *very* stupid idea to touch certain other ones (`SIGSEGV`, |
| //! `SIGFPE`, `SIGILL`). Therefore, this library will panic if any attempt at manipulating these is |
| //! made. There are some use cases for redefining the latter ones, but these are not well served by |
| //! this library and you really *really* have to know what you're doing and are generally on your |
| //! own doing that. |
| //! |
| //! # Signal masks |
| //! |
| //! As the library uses `sigaction` under the hood, signal masking works as expected (eg. with |
| //! `pthread_sigmask`). This means, signals will *not* be delivered if the signal is masked in all |
| //! program's threads. |
| //! |
| //! By the way, if you do want to modify the signal mask (or do other Unix-specific magic), the |
| //! [nix](https://crates.io/crates/nix) crate offers safe interface to many low-level functions, |
| //! including |
| //! [`pthread_sigmask`](https://docs.rs/nix/0.11.0/nix/sys/signal/fn.pthread_sigmask.html). |
| //! |
| //! # Portability |
| //! |
| //! It should work on any POSIX.1-2001 system, which are all the major big OSes with the notable |
| //! exception of Windows. |
| //! |
| //! Non-standard signals are also supported. Pass the signal value directly from `libc` or use |
| //! the numeric value directly. |
| //! |
| //! ```rust |
| //! use std::sync::Arc; |
| //! use std::sync::atomic::{AtomicBool}; |
| //! let term = Arc::new(AtomicBool::new(false)); |
| //! let _ = signal_hook::flag::register(libc::SIGINT, Arc::clone(&term)); |
| //! ``` |
| //! |
| //! This crate includes a limited support for Windows, based on `signal`/`raise` in the CRT. |
| //! There are differences in both API and behavior: |
| //! |
| //! - `iterator` and `pipe` are not yet implemented. |
| //! - We have only a few signals: `SIGABRT`, `SIGABRT_COMPAT`, `SIGBREAK`, |
| //! `SIGFPE`, `SIGILL`, `SIGINT`, `SIGSEGV` and `SIGTERM`. |
| //! - Due to lack of signal blocking, there's a race condition. |
| //! After the call to `signal`, there's a moment where we miss a signal. |
| //! That means when you register a handler, there may be a signal which invokes |
| //! neither the default handler or the handler you register. |
| //! - Handlers registered by `signal` in Windows are cleared on first signal. |
| //! To match behavior in other platforms, we re-register the handler each time the handler is |
| //! called, but there's a moment where we miss a handler. |
| //! That means when you receive two signals in a row, there may be a signal which invokes |
| //! the default handler, nevertheless you certainly have registered the handler. |
| //! |
| //! Moreover, signals won't work as you expected. `SIGTERM` isn't actually used and |
| //! not all `Ctrl-C`s are turned into `SIGINT`. |
| //! |
| //! Patches to improve Windows support in this library are welcome. |
| //! |
| //! # Examples |
| //! |
| //! ```rust |
| //! extern crate signal_hook; |
| //! |
| //! use std::io::Error; |
| //! use std::sync::Arc; |
| //! use std::sync::atomic::{AtomicBool, Ordering}; |
| //! |
| //! fn main() -> Result<(), Error> { |
| //! let term = Arc::new(AtomicBool::new(false)); |
| //! signal_hook::flag::register(signal_hook::SIGTERM, Arc::clone(&term))?; |
| //! while !term.load(Ordering::Relaxed) { |
| //! // Do some time-limited stuff here |
| //! // (if this could block forever, then there's no guarantee the signal will have any |
| //! // effect). |
| //! # |
| //! # // Hack to terminate the example, not part of the real code. |
| //! # term.store(true, Ordering::Relaxed); |
| //! } |
| //! Ok(()) |
| //! } |
| //! ``` |
| //! |
| //! # Features |
| //! |
| //! * `mio-support`: The [`Signals` iterator](iterator/struct.Signals.html) becomes pluggable into |
| //! mio 0.6. |
| //! * `mio-0_7-support`: The [`Signals` iterator](iterator/struct.Signals.html) becomes pluggable into |
| //! mio 0.7. |
| //! * `tokio-support`: The [`Signals`](iterator/struct.Signals.html) can be turned into |
| //! [`Async`](iterator/struct.Async.html), which provides a `Stream` interface for integration in |
| //! the asynchronous world. |
| |
| </span><span class="attribute">#[cfg(feature = <span class="string">"tokio-support"</span>)] |
| </span><span class="kw">extern crate </span>futures; |
| <span class="kw">extern crate </span>libc; |
| <span class="attribute">#[cfg(feature = <span class="string">"mio-support"</span>)] |
| </span><span class="kw">extern crate </span>mio; |
| <span class="attribute">#[cfg(any(test, feature = <span class="string">"mio-0_7-support"</span>))] |
| </span><span class="kw">extern crate </span>mio_0_7; |
| <span class="kw">extern crate </span>signal_hook_registry; |
| <span class="attribute">#[cfg(feature = <span class="string">"tokio-support"</span>)] |
| </span><span class="kw">extern crate </span>tokio_reactor; |
| |
| <span class="kw">pub mod </span>cleanup; |
| <span class="kw">pub mod </span>flag; |
| <span class="attribute">#[cfg(not(windows))] |
| </span><span class="kw">pub mod </span>iterator; |
| <span class="attribute">#[cfg(not(windows))] |
| </span><span class="kw">pub mod </span>pipe; |
| |
| <span class="attribute">#[cfg(not(windows))] |
| </span><span class="kw">pub use </span>libc::{ |
| SIGABRT, SIGALRM, SIGBUS, SIGCHLD, SIGCONT, SIGFPE, SIGHUP, SIGILL, SIGINT, SIGIO, SIGKILL, |
| SIGPIPE, SIGPROF, SIGQUIT, SIGSEGV, SIGSTOP, SIGSYS, SIGTERM, SIGTRAP, SIGUSR1, SIGUSR2, |
| SIGWINCH, |
| }; |
| |
| <span class="attribute">#[cfg(windows)] |
| </span><span class="kw">pub use </span>libc::{SIGABRT, SIGFPE, SIGILL, SIGINT, SIGSEGV, SIGTERM}; |
| |
| <span class="comment">// NOTE: they perhaps deserve backport to libc. |
| </span><span class="attribute">#[cfg(windows)] |
| </span><span class="doccomment">/// Same as `SIGABRT`, but the number is compatible to other platforms. |
| </span><span class="kw">pub const </span>SIGABRT_COMPAT: libc::c_int = <span class="number">6</span>; |
| <span class="attribute">#[cfg(windows)] |
| </span><span class="doccomment">/// Ctrl-Break is pressed for Windows Console processes. |
| </span><span class="kw">pub const </span>SIGBREAK: libc::c_int = <span class="number">21</span>; |
| |
| <span class="kw">pub use </span>signal_hook_registry::{register, unregister, SigId, FORBIDDEN}; |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="signal_hook" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |