| <!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="Reads bytes from a source."><meta name="keywords" content="rust, rustlang, rust-lang, AsyncReadExt"><title>AsyncReadExt in tokio::io - Rust</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" 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href="../../tokio/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../../tokio/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2 class="location"><a href="#">AsyncReadExt</a></h2><div class="sidebar-elems"><section><h3><a href="#provided-methods">Provided Methods</a></h3><ul class="block"><li><a href="#method.chain">chain</a></li><li><a href="#method.read">read</a></li><li><a href="#method.read_buf">read_buf</a></li><li><a href="#method.read_exact">read_exact</a></li><li><a href="#method.read_f32">read_f32</a></li><li><a href="#method.read_f32_le">read_f32_le</a></li><li><a href="#method.read_f64">read_f64</a></li><li><a href="#method.read_f64_le">read_f64_le</a></li><li><a href="#method.read_i128">read_i128</a></li><li><a href="#method.read_i128_le">read_i128_le</a></li><li><a href="#method.read_i16">read_i16</a></li><li><a href="#method.read_i16_le">read_i16_le</a></li><li><a href="#method.read_i32">read_i32</a></li><li><a href="#method.read_i32_le">read_i32_le</a></li><li><a href="#method.read_i64">read_i64</a></li><li><a href="#method.read_i64_le">read_i64_le</a></li><li><a href="#method.read_i8">read_i8</a></li><li><a href="#method.read_to_end">read_to_end</a></li><li><a href="#method.read_to_string">read_to_string</a></li><li><a href="#method.read_u128">read_u128</a></li><li><a href="#method.read_u128_le">read_u128_le</a></li><li><a href="#method.read_u16">read_u16</a></li><li><a href="#method.read_u16_le">read_u16_le</a></li><li><a href="#method.read_u32">read_u32</a></li><li><a href="#method.read_u32_le">read_u32_le</a></li><li><a href="#method.read_u64">read_u64</a></li><li><a href="#method.read_u64_le">read_u64_le</a></li><li><a href="#method.read_u8">read_u8</a></li><li><a href="#method.take">take</a></li></ul><h3><a href="#implementors">Implementors</a></h3></section><h2><a href="index.html">In tokio::io</a></h2></div></nav><main><div class="width-limiter"><nav class="sub"><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="main-heading"><h1 class="fqn">Trait <a href="../index.html">tokio</a>::<wbr><a href="index.html">io</a>::<wbr><a class="trait" href="#">AsyncReadExt</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../../src/tokio/io/util/async_read_ext.rs.html#62-1291">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="item-decl"><pre class="rust trait"><code>pub trait AsyncReadExt: <a class="trait" href="trait.AsyncRead.html" title="trait tokio::io::AsyncRead">AsyncRead</a> { |
| <details class="rustdoc-toggle type-contents-toggle"><summary class="hideme"><span>Show 29 methods</span></summary> fn <a href="#method.chain" class="fnname">chain</a><R>(self, next: R) -> Chain<Self, R><br> <span class="where">where<br> Self: Sized,<br> R: <a class="trait" href="trait.AsyncRead.html" title="trait tokio::io::AsyncRead">AsyncRead</a></span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read" class="fnname">read</a><'a>(&'a mut self, buf: &'a mut [u8]) -> Read<'a, Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_buf" class="fnname">read_buf</a><'a, B>(&'a mut self, buf: &'a mut B) -> ReadBuf<'a, Self, B><br> <span class="where">where<br> Self: Sized + Unpin,<br> B: <a class="trait" href="../../bytes/buf/buf_mut/trait.BufMut.html" title="trait bytes::buf::buf_mut::BufMut">BufMut</a></span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_exact" class="fnname">read_exact</a><'a>(&'a mut self, buf: &'a mut [u8]) -> ReadExact<'a, Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_u8" class="fnname">read_u8</a><'a>(&'a mut self) -> ReadU8<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_i8" class="fnname">read_i8</a><'a>(&'a mut self) -> ReadI8<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_u16" class="fnname">read_u16</a><'a>(&'a mut self) -> ReadU16<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_i16" class="fnname">read_i16</a><'a>(&'a mut self) -> ReadI16<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_u32" class="fnname">read_u32</a><'a>(&'a mut self) -> ReadU32<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_i32" class="fnname">read_i32</a><'a>(&'a mut self) -> ReadI32<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_u64" class="fnname">read_u64</a><'a>(&'a mut self) -> ReadU64<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_i64" class="fnname">read_i64</a><'a>(&'a mut self) -> ReadI64<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_u128" class="fnname">read_u128</a><'a>(&'a mut self) -> ReadU128<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_i128" class="fnname">read_i128</a><'a>(&'a mut self) -> ReadI128<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_f32" class="fnname">read_f32</a><'a>(&'a mut self) -> ReadF32<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_f64" class="fnname">read_f64</a><'a>(&'a mut self) -> ReadF64<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_u16_le" class="fnname">read_u16_le</a><'a>(&'a mut self) -> ReadU16Le<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_i16_le" class="fnname">read_i16_le</a><'a>(&'a mut self) -> ReadI16Le<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_u32_le" class="fnname">read_u32_le</a><'a>(&'a mut self) -> ReadU32Le<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_i32_le" class="fnname">read_i32_le</a><'a>(&'a mut self) -> ReadI32Le<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_u64_le" class="fnname">read_u64_le</a><'a>(&'a mut self) -> ReadU64Le<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_i64_le" class="fnname">read_i64_le</a><'a>(&'a mut self) -> ReadI64Le<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_u128_le" class="fnname">read_u128_le</a><'a>(&'a mut self) -> ReadU128Le<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_i128_le" class="fnname">read_i128_le</a><'a>(&'a mut self) -> ReadI128Le<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_f32_le" class="fnname">read_f32_le</a><'a>(&'a mut self) -> ReadF32Le<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_f64_le" class="fnname">read_f64_le</a><'a>(&'a mut self) -> ReadF64Le<&'a mut Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_to_end" class="fnname">read_to_end</a><'a>(&'a mut self, buf: &'a mut Vec<u8>) -> ReadToEnd<'a, Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.read_to_string" class="fnname">read_to_string</a><'a>(<br> &'a mut self,<br> dst: &'a mut String<br> ) -> ReadToString<'a, Self><br> <span class="where">where<br> Self: Unpin</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.take" class="fnname">take</a>(self, limit: u64) -> <a class="struct" href="struct.Take.html" title="struct tokio::io::Take">Take</a><Self><br> <span class="where">where<br> Self: Sized</span>, |
| { ... } |
| </details>}</code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Reads bytes from a source.</p> |
| <p>Implemented as an extension trait, adding utility methods to all |
| <a href="trait.AsyncRead.html"><code>AsyncRead</code></a> types. Callers will tend to import this trait instead of |
| <a href="trait.AsyncRead.html"><code>AsyncRead</code></a>.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::fs::File; |
| <span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>f = File::open(<span class="string">"foo.txt"</span>).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer = [<span class="number">0</span>; <span class="number">10</span>]; |
| |
| <span class="comment">// The `read` method is defined by this trait. |
| </span><span class="kw">let </span>n = f.read(<span class="kw-2">&mut </span>buffer[..]).<span class="kw">await</span><span class="question-mark">?</span>; |
| |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| <p>See <a href="index.html" title="crate::io">module</a> documentation for more details.</p> |
| </div></details><h2 id="provided-methods" class="small-section-header">Provided Methods<a href="#provided-methods" class="anchor"></a></h2><div class="methods"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.chain" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#92-98">source</a><h4 class="code-header">fn <a href="#method.chain" class="fnname">chain</a><R>(self, next: R) -> Chain<Self, R><span class="where fmt-newline">where<br> Self: Sized,<br> R: <a class="trait" href="trait.AsyncRead.html" title="trait tokio::io::AsyncRead">AsyncRead</a>,</span></h4></section></summary><div class="docblock"><p>Creates a new <code>AsyncRead</code> instance that chains this stream with |
| <code>next</code>.</p> |
| <p>The returned <code>AsyncRead</code> instance will first read all bytes from this object |
| until EOF is encountered. Afterwards the output is equivalent to the |
| output of <code>next</code>.</p> |
| <h5 id="examples"><a href="#examples">Examples</a></h5> |
| <p>[<code>File</code>][crate::fs::File]s implement <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::fs::File; |
| <span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span>f1 = File::open(<span class="string">"foo.txt"</span>).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="kw">let </span>f2 = File::open(<span class="string">"bar.txt"</span>).<span class="kw">await</span><span class="question-mark">?</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>handle = f1.chain(f2); |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer = String::new(); |
| |
| <span class="comment">// read the value into a String. We could use any AsyncRead |
| // method here, this is just one example. |
| </span>handle.read_to_string(<span class="kw-2">&mut </span>buffer).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#168-173">source</a><h4 class="code-header">fn <a href="#method.read" class="fnname">read</a><'a>(&'a mut self, buf: &'a mut [u8]) -> Read<'a, Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Pulls some bytes from this source into the specified buffer, |
| returning how many bytes were read.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&mut </span>[u8]) -> io::Result<usize>;</code></pre></div> |
| <p>This method does not provide any guarantees about whether it |
| completes immediately or asynchronously.</p> |
| <h5 id="return"><a href="#return">Return</a></h5> |
| <p>If the return value of this method is <code>Ok(n)</code>, then it must be |
| guaranteed that <code>0 <= n <= buf.len()</code>. A nonzero <code>n</code> value indicates |
| that the buffer <code>buf</code> has been filled in with <code>n</code> bytes of data from |
| this source. If <code>n</code> is <code>0</code>, then it can indicate one of two |
| scenarios:</p> |
| <ol> |
| <li>This reader has reached its “end of file” and will likely no longer |
| be able to produce bytes. Note that this does not mean that the |
| reader will <em>always</em> no longer be able to produce bytes.</li> |
| <li>The buffer specified was 0 bytes in length.</li> |
| </ol> |
| <p>No guarantees are provided about the contents of <code>buf</code> when this |
| function is called, implementations cannot rely on any property of the |
| contents of <code>buf</code> being <code>true</code>. It is recommended that <em>implementations</em> |
| only write data to <code>buf</code> instead of reading its contents.</p> |
| <p>Correspondingly, however, <em>callers</em> of this method may not assume |
| any guarantees about how the implementation uses <code>buf</code>. It is |
| possible that the code that’s supposed to write to the buffer might |
| also read from it. It is your responsibility to make sure that <code>buf</code> |
| is initialized before calling <code>read</code>.</p> |
| <h5 id="errors"><a href="#errors">Errors</a></h5> |
| <p>If this function encounters any form of I/O or other error, an error |
| variant will be returned. If an error is returned then it must be |
| guaranteed that no bytes were read.</p> |
| <h5 id="cancel-safety"><a href="#cancel-safety">Cancel safety</a></h5> |
| <p>This method is cancel safe. If you use it as the event in a |
| <a href="../macro.select.html"><code>tokio::select!</code></a> statement and some other branch |
| completes first, then it is guaranteed that no data was read.</p> |
| <h5 id="examples-1"><a href="#examples-1">Examples</a></h5> |
| <p>[<code>File</code>][crate::fs::File]s implement <code>Read</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::fs::File; |
| <span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>f = File::open(<span class="string">"foo.txt"</span>).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer = [<span class="number">0</span>; <span class="number">10</span>]; |
| |
| <span class="comment">// read up to 10 bytes |
| </span><span class="kw">let </span>n = f.read(<span class="kw-2">&mut </span>buffer[..]).<span class="kw">await</span><span class="question-mark">?</span>; |
| |
| <span class="macro">println!</span>(<span class="string">"The bytes: {:?}"</span>, <span class="kw-2">&</span>buffer[..n]); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_buf" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#243-249">source</a><h4 class="code-header">fn <a href="#method.read_buf" class="fnname">read_buf</a><'a, B>(&'a mut self, buf: &'a mut B) -> ReadBuf<'a, Self, B><span class="where fmt-newline">where<br> Self: Sized + Unpin,<br> B: <a class="trait" href="../../bytes/buf/buf_mut/trait.BufMut.html" title="trait bytes::buf::buf_mut::BufMut">BufMut</a>,</span></h4></section></summary><div class="docblock"><p>Pulls some bytes from this source into the specified buffer, |
| advancing the buffer’s internal cursor.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_buf<B: BufMut>(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&mut </span>B) -> io::Result<usize>;</code></pre></div> |
| <p>Usually, only a single <code>read</code> syscall is issued, even if there is |
| more space in the supplied buffer.</p> |
| <p>This method does not provide any guarantees about whether it |
| completes immediately or asynchronously.</p> |
| <h5 id="return-1"><a href="#return-1">Return</a></h5> |
| <p>A nonzero <code>n</code> value indicates that the buffer <code>buf</code> has been filled |
| in with <code>n</code> bytes of data from this source. If <code>n</code> is <code>0</code>, then it |
| can indicate one of two scenarios:</p> |
| <ol> |
| <li>This reader has reached its “end of file” and will likely no longer |
| be able to produce bytes. Note that this does not mean that the |
| reader will <em>always</em> no longer be able to produce bytes.</li> |
| <li>The buffer specified had a remaining capacity of zero.</li> |
| </ol> |
| <h5 id="errors-1"><a href="#errors-1">Errors</a></h5> |
| <p>If this function encounters any form of I/O or other error, an error |
| variant will be returned. If an error is returned then it must be |
| guaranteed that no bytes were read.</p> |
| <h5 id="cancel-safety-1"><a href="#cancel-safety-1">Cancel safety</a></h5> |
| <p>This method is cancel safe. If you use it as the event in a |
| <a href="../macro.select.html"><code>tokio::select!</code></a> statement and some other branch |
| completes first, then it is guaranteed that no data was read.</p> |
| <h5 id="examples-2"><a href="#examples-2">Examples</a></h5> |
| <p><a href="crate::fs::File"><code>File</code></a> implements <code>Read</code> and <a href="../../bytes/bytes_mut/struct.BytesMut.html"><code>BytesMut</code></a> implements <a href="../../bytes/buf/buf_mut/trait.BufMut.html"><code>BufMut</code></a>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::fs::File; |
| <span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>bytes::BytesMut; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>f = File::open(<span class="string">"foo.txt"</span>).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer = BytesMut::with_capacity(<span class="number">10</span>); |
| |
| <span class="macro">assert!</span>(buffer.is_empty()); |
| |
| <span class="comment">// read up to 10 bytes, note that the return value is not needed |
| // to access the data that was read as `buffer`'s internal |
| // cursor is updated. |
| </span>f.read_buf(<span class="kw-2">&mut </span>buffer).<span class="kw">await</span><span class="question-mark">?</span>; |
| |
| <span class="macro">println!</span>(<span class="string">"The bytes: {:?}"</span>, <span class="kw-2">&</span>buffer[..]); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_exact" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#304-309">source</a><h4 class="code-header">fn <a href="#method.read_exact" class="fnname">read_exact</a><'a>(&'a mut self, buf: &'a mut [u8]) -> ReadExact<'a, Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads the exact number of bytes required to fill <code>buf</code>.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_exact(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&mut </span>[u8]) -> io::Result<usize>;</code></pre></div> |
| <p>This function reads as many bytes as necessary to completely fill |
| the specified buffer <code>buf</code>.</p> |
| <h5 id="errors-2"><a href="#errors-2">Errors</a></h5> |
| <p>If the operation encounters an “end of file” before completely |
| filling the buffer, it returns an error of the kind |
| <a href="std::io::ErrorKind::UnexpectedEof"><code>ErrorKind::UnexpectedEof</code></a>. The contents of <code>buf</code> are unspecified |
| in this case.</p> |
| <p>If any other read error is encountered then the operation |
| immediately returns. The contents of <code>buf</code> are unspecified in this |
| case.</p> |
| <p>If this operation returns an error, it is unspecified how many bytes |
| it has read, but it will never read more than would be necessary to |
| completely fill the buffer.</p> |
| <h5 id="cancel-safety-2"><a href="#cancel-safety-2">Cancel safety</a></h5> |
| <p>This method is not cancellation safe. If the method is used as the |
| event in a <a href="../macro.select.html"><code>tokio::select!</code></a> statement and some |
| other branch completes first, then some data may already have been |
| read into <code>buf</code>.</p> |
| <h5 id="examples-3"><a href="#examples-3">Examples</a></h5> |
| <p>[<code>File</code>][crate::fs::File]s implement <code>Read</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::fs::File; |
| <span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>f = File::open(<span class="string">"foo.txt"</span>).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer = [<span class="number">0</span>; <span class="number">10</span>]; |
| |
| <span class="comment">// read exactly 10 bytes |
| </span>f.read_exact(<span class="kw-2">&mut </span>buffer).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_u8" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_u8" class="fnname">read_u8</a><'a>(&'a mut self) -> ReadU8<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an unsigned 8 bit integer from the underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_u8(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<u8>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-3"><a href="#errors-3">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-4"><a href="#examples-4">Examples</a></h5> |
| <p>Read unsigned 8 bit integers from an <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">2</span>, <span class="number">5</span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">2</span>, reader.read_u8().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="macro">assert_eq!</span>(<span class="number">5</span>, reader.read_u8().<span class="kw">await</span><span class="question-mark">?</span>); |
| |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_i8" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_i8" class="fnname">read_i8</a><'a>(&'a mut self) -> ReadI8<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads a signed 8 bit integer from the underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_i8(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<i8>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-4"><a href="#errors-4">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-5"><a href="#examples-5">Examples</a></h5> |
| <p>Read unsigned 8 bit integers from an <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0x02</span>, <span class="number">0xfb</span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">2</span>, reader.read_i8().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="macro">assert_eq!</span>(-<span class="number">5</span>, reader.read_i8().<span class="kw">await</span><span class="question-mark">?</span>); |
| |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_u16" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_u16" class="fnname">read_u16</a><'a>(&'a mut self) -> ReadU16<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an unsigned 16-bit integer in big-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_u16(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<u16>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-5"><a href="#errors-5">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-6"><a href="#examples-6">Examples</a></h5> |
| <p>Read unsigned 16 bit big-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">2</span>, <span class="number">5</span>, <span class="number">3</span>, <span class="number">0</span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">517</span>, reader.read_u16().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="macro">assert_eq!</span>(<span class="number">768</span>, reader.read_u16().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_i16" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_i16" class="fnname">read_i16</a><'a>(&'a mut self) -> ReadI16<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads a signed 16-bit integer in big-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_i16(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<i16>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-6"><a href="#errors-6">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-7"><a href="#examples-7">Examples</a></h5> |
| <p>Read signed 16 bit big-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0x00</span>, <span class="number">0xc1</span>, <span class="number">0xff</span>, <span class="number">0x7c</span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">193</span>, reader.read_i16().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="macro">assert_eq!</span>(-<span class="number">132</span>, reader.read_i16().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_u32" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_u32" class="fnname">read_u32</a><'a>(&'a mut self) -> ReadU32<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an unsigned 32-bit integer in big-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_u32(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<u32>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-7"><a href="#errors-7">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-8"><a href="#examples-8">Examples</a></h5> |
| <p>Read unsigned 32-bit big-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0x00</span>, <span class="number">0x00</span>, <span class="number">0x01</span>, <span class="number">0x0b</span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">267</span>, reader.read_u32().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_i32" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_i32" class="fnname">read_i32</a><'a>(&'a mut self) -> ReadI32<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads a signed 32-bit integer in big-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_i32(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<i32>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-8"><a href="#errors-8">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-9"><a href="#examples-9">Examples</a></h5> |
| <p>Read signed 32-bit big-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0x7a</span>, <span class="number">0x33</span>]); |
| |
| <span class="macro">assert_eq!</span>(-<span class="number">34253</span>, reader.read_i32().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_u64" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_u64" class="fnname">read_u64</a><'a>(&'a mut self) -> ReadU64<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an unsigned 64-bit integer in big-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_u64(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<u64>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-9"><a href="#errors-9">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-10"><a href="#examples-10">Examples</a></h5> |
| <p>Read unsigned 64-bit big-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[ |
| <span class="number">0x00</span>, <span class="number">0x03</span>, <span class="number">0x43</span>, <span class="number">0x95</span>, <span class="number">0x4d</span>, <span class="number">0x60</span>, <span class="number">0x86</span>, <span class="number">0x83 |
| </span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">918733457491587</span>, reader.read_u64().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_i64" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_i64" class="fnname">read_i64</a><'a>(&'a mut self) -> ReadI64<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an signed 64-bit integer in big-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_i64(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<i64>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-10"><a href="#errors-10">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-11"><a href="#examples-11">Examples</a></h5> |
| <p>Read signed 64-bit big-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0x80</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>]); |
| |
| <span class="macro">assert_eq!</span>(i64::MIN, reader.read_i64().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_u128" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_u128" class="fnname">read_u128</a><'a>(&'a mut self) -> ReadU128<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an unsigned 128-bit integer in big-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_u128(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<u128>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-11"><a href="#errors-11">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-12"><a href="#examples-12">Examples</a></h5> |
| <p>Read unsigned 128-bit big-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[ |
| <span class="number">0x00</span>, <span class="number">0x03</span>, <span class="number">0x43</span>, <span class="number">0x95</span>, <span class="number">0x4d</span>, <span class="number">0x60</span>, <span class="number">0x86</span>, <span class="number">0x83</span>, |
| <span class="number">0x00</span>, <span class="number">0x03</span>, <span class="number">0x43</span>, <span class="number">0x95</span>, <span class="number">0x4d</span>, <span class="number">0x60</span>, <span class="number">0x86</span>, <span class="number">0x83 |
| </span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">16947640962301618749969007319746179</span>, reader.read_u128().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_i128" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_i128" class="fnname">read_i128</a><'a>(&'a mut self) -> ReadI128<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an signed 128-bit integer in big-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_i128(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<i128>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-12"><a href="#errors-12">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-13"><a href="#examples-13">Examples</a></h5> |
| <p>Read signed 128-bit big-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[ |
| <span class="number">0x80</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, |
| <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0 |
| </span>]); |
| |
| <span class="macro">assert_eq!</span>(i128::MIN, reader.read_i128().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_f32" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_f32" class="fnname">read_f32</a><'a>(&'a mut self) -> ReadF32<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an 32-bit floating point type in big-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_f32(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<f32>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-13"><a href="#errors-13">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-14"><a href="#examples-14">Examples</a></h5> |
| <p>Read 32-bit floating point type from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0xff</span>, <span class="number">0x7f</span>, <span class="number">0xff</span>, <span class="number">0xff</span>]); |
| |
| <span class="macro">assert_eq!</span>(f32::MIN, reader.read_f32().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_f64" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_f64" class="fnname">read_f64</a><'a>(&'a mut self) -> ReadF64<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an 64-bit floating point type in big-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_f64(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<f64>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-14"><a href="#errors-14">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-15"><a href="#examples-15">Examples</a></h5> |
| <p>Read 64-bit floating point type from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[ |
| <span class="number">0xff</span>, <span class="number">0xef</span>, <span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0xff |
| </span>]); |
| |
| <span class="macro">assert_eq!</span>(f64::MIN, reader.read_f64().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_u16_le" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_u16_le" class="fnname">read_u16_le</a><'a>(&'a mut self) -> ReadU16Le<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an unsigned 16-bit integer in little-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_u16_le(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<u16>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-15"><a href="#errors-15">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-16"><a href="#examples-16">Examples</a></h5> |
| <p>Read unsigned 16 bit little-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">2</span>, <span class="number">5</span>, <span class="number">3</span>, <span class="number">0</span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">1282</span>, reader.read_u16_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="macro">assert_eq!</span>(<span class="number">3</span>, reader.read_u16_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_i16_le" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_i16_le" class="fnname">read_i16_le</a><'a>(&'a mut self) -> ReadI16Le<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads a signed 16-bit integer in little-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_i16_le(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<i16>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-16"><a href="#errors-16">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-17"><a href="#examples-17">Examples</a></h5> |
| <p>Read signed 16 bit little-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0x00</span>, <span class="number">0xc1</span>, <span class="number">0xff</span>, <span class="number">0x7c</span>]); |
| |
| <span class="macro">assert_eq!</span>(-<span class="number">16128</span>, reader.read_i16_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="macro">assert_eq!</span>(<span class="number">31999</span>, reader.read_i16_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_u32_le" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_u32_le" class="fnname">read_u32_le</a><'a>(&'a mut self) -> ReadU32Le<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an unsigned 32-bit integer in little-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_u32_le(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<u32>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-17"><a href="#errors-17">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-18"><a href="#examples-18">Examples</a></h5> |
| <p>Read unsigned 32-bit little-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0x00</span>, <span class="number">0x00</span>, <span class="number">0x01</span>, <span class="number">0x0b</span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">184614912</span>, reader.read_u32_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_i32_le" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_i32_le" class="fnname">read_i32_le</a><'a>(&'a mut self) -> ReadI32Le<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads a signed 32-bit integer in little-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_i32_le(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<i32>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-18"><a href="#errors-18">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-19"><a href="#examples-19">Examples</a></h5> |
| <p>Read signed 32-bit little-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0x7a</span>, <span class="number">0x33</span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">863698943</span>, reader.read_i32_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_u64_le" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_u64_le" class="fnname">read_u64_le</a><'a>(&'a mut self) -> ReadU64Le<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an unsigned 64-bit integer in little-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_u64_le(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<u64>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-19"><a href="#errors-19">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-20"><a href="#examples-20">Examples</a></h5> |
| <p>Read unsigned 64-bit little-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[ |
| <span class="number">0x00</span>, <span class="number">0x03</span>, <span class="number">0x43</span>, <span class="number">0x95</span>, <span class="number">0x4d</span>, <span class="number">0x60</span>, <span class="number">0x86</span>, <span class="number">0x83 |
| </span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">9477368352180732672</span>, reader.read_u64_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_i64_le" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_i64_le" class="fnname">read_i64_le</a><'a>(&'a mut self) -> ReadI64Le<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an signed 64-bit integer in little-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_i64_le(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<i64>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-20"><a href="#errors-20">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-21"><a href="#examples-21">Examples</a></h5> |
| <p>Read signed 64-bit little-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0x80</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">128</span>, reader.read_i64_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_u128_le" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_u128_le" class="fnname">read_u128_le</a><'a>(&'a mut self) -> ReadU128Le<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an unsigned 128-bit integer in little-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_u128_le(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<u128>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-21"><a href="#errors-21">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-22"><a href="#examples-22">Examples</a></h5> |
| <p>Read unsigned 128-bit little-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[ |
| <span class="number">0x00</span>, <span class="number">0x03</span>, <span class="number">0x43</span>, <span class="number">0x95</span>, <span class="number">0x4d</span>, <span class="number">0x60</span>, <span class="number">0x86</span>, <span class="number">0x83</span>, |
| <span class="number">0x00</span>, <span class="number">0x03</span>, <span class="number">0x43</span>, <span class="number">0x95</span>, <span class="number">0x4d</span>, <span class="number">0x60</span>, <span class="number">0x86</span>, <span class="number">0x83 |
| </span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">174826588484952389081207917399662330624</span>, reader.read_u128_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_i128_le" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_i128_le" class="fnname">read_i128_le</a><'a>(&'a mut self) -> ReadI128Le<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an signed 128-bit integer in little-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_i128_le(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<i128>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-22"><a href="#errors-22">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-23"><a href="#examples-23">Examples</a></h5> |
| <p>Read signed 128-bit little-endian integers from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[ |
| <span class="number">0x80</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, |
| <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>, <span class="number">0 |
| </span>]); |
| |
| <span class="macro">assert_eq!</span>(<span class="number">128</span>, reader.read_i128_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_f32_le" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_f32_le" class="fnname">read_f32_le</a><'a>(&'a mut self) -> ReadF32Le<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an 32-bit floating point type in little-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_f32_le(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<f32>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-23"><a href="#errors-23">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-24"><a href="#examples-24">Examples</a></h5> |
| <p>Read 32-bit floating point type from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[<span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0x7f</span>, <span class="number">0xff</span>]); |
| |
| <span class="macro">assert_eq!</span>(f32::MIN, reader.read_f32_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_f64_le" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#311-1153">source</a><h4 class="code-header">fn <a href="#method.read_f64_le" class="fnname">read_f64_le</a><'a>(&'a mut self) -> ReadF64Le<&'a mut Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads an 64-bit floating point type in little-endian order from the |
| underlying reader.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_f64_le(<span class="kw-2">&mut </span><span class="self">self</span>) -> io::Result<f64>;</code></pre></div> |
| <p>It is recommended to use a buffered reader to avoid excessive |
| syscalls.</p> |
| <h5 id="errors-24"><a href="#errors-24">Errors</a></h5> |
| <p>This method returns the same errors as <a href="trait.AsyncReadExt.html#method.read_exact"><code>AsyncReadExt::read_exact</code></a>.</p> |
| <h5 id="examples-25"><a href="#examples-25">Examples</a></h5> |
| <p>Read 64-bit floating point type from a <code>AsyncRead</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| |
| <span class="kw">use </span>std::io::Cursor; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>reader = Cursor::new(<span class="macro">vec!</span>[ |
| <span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0xff</span>, <span class="number">0xef</span>, <span class="number">0xff |
| </span>]); |
| |
| <span class="macro">assert_eq!</span>(f64::MIN, reader.read_f64_le().<span class="kw">await</span><span class="question-mark">?</span>); |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_to_end" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#1200-1205">source</a><h4 class="code-header">fn <a href="#method.read_to_end" class="fnname">read_to_end</a><'a>(&'a mut self, buf: &'a mut Vec<u8>) -> ReadToEnd<'a, Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads all bytes until EOF in this source, placing them into <code>buf</code>.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_to_end(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&mut </span>Vec<u8>) -> io::Result<usize>;</code></pre></div> |
| <p>All bytes read from this source will be appended to the specified |
| buffer <code>buf</code>. This function will continuously call <a href="trait.AsyncReadExt.html#method.read"><code>read()</code></a> to |
| append more data to <code>buf</code> until <a href="trait.AsyncReadExt.html#method.read"><code>read()</code></a> returns <code>Ok(0)</code>.</p> |
| <p>If successful, the total number of bytes read is returned.</p> |
| <h5 id="errors-25"><a href="#errors-25">Errors</a></h5> |
| <p>If a read error is encountered then the <code>read_to_end</code> operation |
| immediately completes. Any bytes which have already been read will |
| be appended to <code>buf</code>.</p> |
| <h5 id="examples-26"><a href="#examples-26">Examples</a></h5> |
| <p>[<code>File</code>][crate::fs::File]s implement <code>Read</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| <span class="kw">use </span>tokio::fs::File; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>f = File::open(<span class="string">"foo.txt"</span>).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer = Vec::new(); |
| |
| <span class="comment">// read the whole file |
| </span>f.read_to_end(<span class="kw-2">&mut </span>buffer).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| <p>(See also the <a href="fn@crate::fs::read"><code>tokio::fs::read</code></a> convenience function for reading from a |
| file.)</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.read_to_string" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#1247-1252">source</a><h4 class="code-header">fn <a href="#method.read_to_string" class="fnname">read_to_string</a><'a>(<br> &'a mut self,<br> dst: &'a mut String<br>) -> ReadToString<'a, Self><span class="where fmt-newline">where<br> Self: Unpin,</span></h4></section></summary><div class="docblock"><p>Reads all bytes until EOF in this source, appending them to <code>buf</code>.</p> |
| <p>Equivalent to:</p> |
| |
| <div class="example-wrap ignore"><div class='tooltip'>ⓘ</div><pre class="rust rust-example-rendered"><code><span class="kw">async fn </span>read_to_string(<span class="kw-2">&mut </span><span class="self">self</span>, buf: <span class="kw-2">&mut </span>String) -> io::Result<usize>;</code></pre></div> |
| <p>If successful, the number of bytes which were read and appended to |
| <code>buf</code> is returned.</p> |
| <h5 id="errors-26"><a href="#errors-26">Errors</a></h5> |
| <p>If the data in this stream is <em>not</em> valid UTF-8 then an error is |
| returned and <code>buf</code> is unchanged.</p> |
| <p>See <a href="trait.AsyncReadExt.html#method.read_to_end" title="AsyncReadExt::read_to_end"><code>read_to_end</code></a> for other error semantics.</p> |
| <h5 id="examples-27"><a href="#examples-27">Examples</a></h5> |
| <p>[<code>File</code>][crate::fs::File]s implement <code>Read</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| <span class="kw">use </span>tokio::fs::File; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span><span class="kw-2">mut </span>f = File::open(<span class="string">"foo.txt"</span>).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer = String::new(); |
| |
| f.read_to_string(<span class="kw-2">&mut </span>buffer).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| <p>(See also the <a href="fn@crate::fs::read_to_string"><code>crate::fs::read_to_string</code></a> convenience function for |
| reading from a file.)</p> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.take" class="method has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#1285-1290">source</a><h4 class="code-header">fn <a href="#method.take" class="fnname">take</a>(self, limit: u64) -> <a class="struct" href="struct.Take.html" title="struct tokio::io::Take">Take</a><Self><span class="where fmt-newline">where<br> Self: Sized,</span></h4></section></summary><div class="docblock"><p>Creates an adaptor which reads at most <code>limit</code> bytes from it.</p> |
| <p>This function returns a new instance of <code>AsyncRead</code> which will read |
| at most <code>limit</code> bytes, after which it will always return EOF |
| (<code>Ok(0)</code>). Any read errors will not count towards the number of |
| bytes read and future calls to <a href="trait.AsyncReadExt.html#method.read"><code>read()</code></a> may succeed.</p> |
| <h5 id="examples-28"><a href="#examples-28">Examples</a></h5> |
| <p>[<code>File</code>][crate::fs::File]s implement <code>Read</code>:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>tokio::io::{<span class="self">self</span>, AsyncReadExt}; |
| <span class="kw">use </span>tokio::fs::File; |
| |
| <span class="attribute">#[tokio::main] |
| </span><span class="kw">async fn </span>main() -> io::Result<()> { |
| <span class="kw">let </span>f = File::open(<span class="string">"foo.txt"</span>).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>buffer = [<span class="number">0</span>; <span class="number">5</span>]; |
| |
| <span class="comment">// read at most five bytes |
| </span><span class="kw">let </span><span class="kw-2">mut </span>handle = f.take(<span class="number">5</span>); |
| |
| handle.read(<span class="kw-2">&mut </span>buffer).<span class="kw">await</span><span class="question-mark">?</span>; |
| <span class="prelude-val">Ok</span>(()) |
| }</code></pre></div> |
| </div></details></div><h2 id="implementors" class="small-section-header">Implementors<a href="#implementors" class="anchor"></a></h2><div id="implementors-list"><section id="impl-AsyncReadExt-for-R" class="impl has-srclink"><a class="srclink rightside" href="../../src/tokio/io/util/async_read_ext.rs.html#1294">source</a><a href="#impl-AsyncReadExt-for-R" class="anchor"></a><h3 class="code-header">impl<R: <a class="trait" href="trait.AsyncRead.html" title="trait tokio::io::AsyncRead">AsyncRead</a> + ?Sized> <a class="trait" href="trait.AsyncReadExt.html" title="trait tokio::io::AsyncReadExt">AsyncReadExt</a> for R</h3></section></div><script src="../../implementors/tokio/io/util/async_read_ext/trait.AsyncReadExt.js" async></script></section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="tokio" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
