<!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="A trait to express the ability to construct an object from a raw file descriptor."><title>FromRawFd in rustix::fd - 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><link rel="stylesheet" href="../../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../../static.files/rustdoc-dd39b87e5fcfba68.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="rustix" data-themes="" data-resource-suffix="" data-rustdoc-version="1.81.0-nightly (4bc39f028 2024-06-26)" data-channel="nightly" data-search-js="search-0fe7219eb170c82e.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../../static.files/storage-118b08c4c78b968e.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../static.files/main-20a3ad099b048cf2.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-df360f571f6edeae.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-422f7d1d52889060.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-2c020d218678b618.svg"></head><body class="rustdoc trait"><!--[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="../../rustix/index.html">rustix</a><span class="version">0.38.34</span></h2></div><h2 class="location"><a href="#">FromRawFd</a></h2><div class="sidebar-elems"><section><h3><a href="#required-methods">Required Methods</a></h3><ul class="block"><li><a href="#tymethod.from_raw_fd">from_raw_fd</a></li></ul><h3><a href="#object-safety">Object Safety</a></h3><h3><a href="#implementors">Implementors</a></h3></section><h2><a href="index.html">In rustix::fd</a></h2></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"><h1>Trait <a href="../index.html">rustix</a>::<wbr><a href="index.html">fd</a>::<wbr><a class="trait" href="#">FromRawFd</a><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><span class="out-of-band"><span class="since" title="Stable since Rust version 1.1.0">1.1.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/fd/raw.rs.html#72">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>−</span>]</button></span></div><pre class="rust item-decl"><code>pub trait FromRawFd {
// Required method
unsafe fn <a href="#tymethod.from_raw_fd" class="fn">from_raw_fd</a>(fd: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.i32.html">i32</a>) -> Self;
}</code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>A trait to express the ability to construct an object from a raw file
descriptor.</p>
</div></details><h2 id="required-methods" class="section-header">Required Methods<a href="#required-methods" class="anchor">§</a></h2><div class="methods"><details class="toggle method-toggle" open><summary><section id="tymethod.from_raw_fd" class="method"><span class="rightside"><span class="since" title="Stable since Rust version 1.1.0">1.1.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/fd/raw.rs.html#110">source</a></span><h4 class="code-header">unsafe fn <a href="#tymethod.from_raw_fd" class="fn">from_raw_fd</a>(fd: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.i32.html">i32</a>) -> Self</h4></section></summary><div class="docblock"><p>Constructs a new instance of <code>Self</code> from the given raw file
descriptor.</p>
<p>This function is typically used to <strong>consume ownership</strong> of the
specified file descriptor. When used in this way, the returned object
will take responsibility for closing it when the object goes out of
scope.</p>
<p>However, consuming ownership is not strictly required. Use a
<a href="https://doc.rust-lang.org/nightly/core/convert/trait.From.html#tymethod.from" title="associated function core::convert::From::from"><code>From<OwnedFd>::from</code></a> implementation for an API which strictly
consumes ownership.</p>
<h5 id="safety"><a class="doc-anchor" href="#safety">§</a>Safety</h5>
<p>The <code>fd</code> passed in must be an <a href="https://doc.rust-lang.org/nightly/std/io/index.html#io-safety" title="mod std::io">owned file descriptor</a>;
in particular, it must be open.</p>
<h5 id="example"><a class="doc-anchor" href="#example">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>std::fs::File;
<span class="attr">#[cfg(any(unix, target_os = <span class="string">"wasi"</span>))]
</span><span class="kw">use </span>std::os::fd::{FromRawFd, IntoRawFd, RawFd};
<span class="kw">let </span>f = File::open(<span class="string">"foo.txt"</span>)<span class="question-mark">?</span>;
<span class="kw">let </span>raw_fd: RawFd = f.into_raw_fd();
<span class="comment">// SAFETY: no other functions should call `from_raw_fd`, so there
// is only one owner for the file descriptor.
</span><span class="kw">let </span>f = <span class="kw">unsafe </span>{ File::from_raw_fd(raw_fd) };</code></pre></div>
</div></details></div><h2 id="object-safety" class="section-header">Object Safety<a href="#object-safety" class="anchor">§</a></h2><div class="object-safety-info">This trait is <b>not</b> <a href="https://doc.rust-lang.org/nightly/reference/items/traits.html#object-safety">object safe</a>.</div><h2 id="implementors" class="section-header">Implementors<a href="#implementors" class="anchor">§</a></h2><div id="implementors-list"><section id="impl-FromRawFd-for-i32" class="impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.48.0">1.48.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/fd/raw.rs.html#160">source</a></span><a href="#impl-FromRawFd-for-i32" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.i32.html">i32</a></h3></section><section id="impl-FromRawFd-for-File" class="impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.1.0">1.1.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/fd/raw.rs.html#175">source</a></span><a href="#impl-FromRawFd-for-File" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/fs/struct.File.html" title="struct std::fs::File">File</a></h3></section><section id="impl-FromRawFd-for-TcpListener" class="impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.1.0">1.1.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/fd/net.rs.html#33">source</a></span><a href="#impl-FromRawFd-for-TcpListener" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/net/tcp/struct.TcpListener.html" title="struct std::net::tcp::TcpListener">TcpListener</a></h3></section><section id="impl-FromRawFd-for-TcpStream" class="impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.1.0">1.1.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/fd/net.rs.html#33">source</a></span><a href="#impl-FromRawFd-for-TcpStream" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/net/tcp/struct.TcpStream.html" title="struct std::net::tcp::TcpStream">TcpStream</a></h3></section><section id="impl-FromRawFd-for-UdpSocket" class="impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.1.0">1.1.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/fd/net.rs.html#33">source</a></span><a href="#impl-FromRawFd-for-UdpSocket" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/net/udp/struct.UdpSocket.html" title="struct std::net::udp::UdpSocket">UdpSocket</a></h3></section><section id="impl-FromRawFd-for-PidFd" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/nightly/src/std/os/linux/process.rs.html#115">source</a><a href="#impl-FromRawFd-for-PidFd" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/os/linux/process/struct.PidFd.html" title="struct std::os::linux::process::PidFd">PidFd</a></h3></section><section id="impl-FromRawFd-for-UnixDatagram" class="impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.10.0">1.10.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/unix/net/datagram.rs.html#944">source</a></span><a href="#impl-FromRawFd-for-UnixDatagram" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/os/unix/net/datagram/struct.UnixDatagram.html" title="struct std::os::unix::net::datagram::UnixDatagram">UnixDatagram</a></h3></section><section id="impl-FromRawFd-for-UnixListener" class="impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.10.0">1.10.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/unix/net/listener.rs.html#324">source</a></span><a href="#impl-FromRawFd-for-UnixListener" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/os/unix/net/listener/struct.UnixListener.html" title="struct std::os::unix::net::listener::UnixListener">UnixListener</a></h3></section><section id="impl-FromRawFd-for-UnixStream" class="impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.10.0">1.10.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/unix/net/stream.rs.html#661">source</a></span><a href="#impl-FromRawFd-for-UnixStream" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/os/unix/net/stream/struct.UnixStream.html" title="struct std::os::unix::net::stream::UnixStream">UnixStream</a></h3></section><section id="impl-FromRawFd-for-Stdio" class="impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.2.0">1.2.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/unix/process.rs.html#361">source</a></span><a href="#impl-FromRawFd-for-Stdio" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/process/struct.Stdio.html" title="struct std::process::Stdio">Stdio</a></h3></section><section id="impl-FromRawFd-for-OwnedFd" class="impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.63.0">1.63.0</span> · <a class="src" href="https://doc.rust-lang.org/nightly/src/std/os/fd/owned.rs.html#151">source</a></span><a href="#impl-FromRawFd-for-OwnedFd" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="trait.FromRawFd.html" title="trait rustix::fd::FromRawFd">FromRawFd</a> for <a class="struct" href="struct.OwnedFd.html" title="struct rustix::fd::OwnedFd">OwnedFd</a></h3></section></div><script src="../../trait.impl/std/os/fd/raw/trait.FromRawFd.js" data-ignore-extern-crates="std" async></script></section></div></main></body></html>