194 lines
8.9 KiB
HTML
194 lines
8.9 KiB
HTML
|
<html>
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
|
||
|
|
<title>use_future_t</title>
|
||
|
|
<link rel="stylesheet" href="../../boostbook.css" type="text/css">
|
||
|
|
<meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
|
||
|
|
<link rel="home" href="../../index.html" title="Asio">
|
||
|
|
<link rel="up" href="../reference.html" title="Reference">
|
||
|
|
<link rel="prev" href="use_future.html" title="use_future">
|
||
|
|
<link rel="next" href="use_future_t/allocator_type.html" title="use_future_t::allocator_type">
|
||
|
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||
|
|
</head>
|
||
|
|
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
|
||
|
|
<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="asio C++ library" width="250" height="60" src="../../asio.png"></td></tr></table>
|
||
|
|
<hr>
|
||
|
|
<div class="spirit-nav">
|
||
|
|
<a accesskey="p" href="use_future.html"><img src="../../prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../home.png" alt="Home"></a><a accesskey="n" href="use_future_t/allocator_type.html"><img src="../../next.png" alt="Next"></a>
|
||
|
|
</div>
|
||
|
|
<div class="section">
|
||
|
|
<div class="titlepage"><div><div><h3 class="title">
|
||
|
|
<a name="asio.reference.use_future_t"></a><a class="link" href="use_future_t.html" title="use_future_t">use_future_t</a>
|
||
|
|
</h3></div></div></div>
|
||
|
|
<p>
|
||
|
|
<a class="indexterm" name="asio.indexterm.use_future_t"></a>
|
||
|
|
</p>
|
||
|
|
<p>
|
||
|
|
A <a class="link" href="../overview/model/completion_tokens.html" title="Completion Tokens">completion token</a>
|
||
|
|
type that causes an asynchronous operation to return a future.
|
||
|
|
</p>
|
||
|
|
<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span>
|
||
|
|
<span class="keyword">typename</span> <span class="identifier">Allocator</span> <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator</span><span class="special"><</span><span class="keyword">void</span><span class="special">>></span>
|
||
|
|
<span class="keyword">class</span> <span class="identifier">use_future_t</span>
|
||
|
|
</pre>
|
||
|
|
<h5>
|
||
|
|
<a name="asio.reference.use_future_t.h0"></a>
|
||
|
|
<span><a name="asio.reference.use_future_t.types"></a></span><a class="link" href="use_future_t.html#asio.reference.use_future_t.types">Types</a>
|
||
|
|
</h5>
|
||
|
|
<div class="informaltable"><table class="table">
|
||
|
|
<colgroup>
|
||
|
|
<col>
|
||
|
|
<col>
|
||
|
|
</colgroup>
|
||
|
|
<thead><tr>
|
||
|
|
<th>
|
||
|
|
<p>
|
||
|
|
Name
|
||
|
|
</p>
|
||
|
|
</th>
|
||
|
|
<th>
|
||
|
|
<p>
|
||
|
|
Description
|
||
|
|
</p>
|
||
|
|
</th>
|
||
|
|
</tr></thead>
|
||
|
|
<tbody><tr>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
<a class="link" href="use_future_t/allocator_type.html" title="use_future_t::allocator_type"><span class="bold"><strong>allocator_type</strong></span></a>
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
The allocator type. The allocator is used when constructing the
|
||
|
|
std::promise object for a given asynchronous operation.
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
</tr></tbody>
|
||
|
|
</table></div>
|
||
|
|
<h5>
|
||
|
|
<a name="asio.reference.use_future_t.h1"></a>
|
||
|
|
<span><a name="asio.reference.use_future_t.member_functions"></a></span><a class="link" href="use_future_t.html#asio.reference.use_future_t.member_functions">Member
|
||
|
|
Functions</a>
|
||
|
|
</h5>
|
||
|
|
<div class="informaltable"><table class="table">
|
||
|
|
<colgroup>
|
||
|
|
<col>
|
||
|
|
<col>
|
||
|
|
</colgroup>
|
||
|
|
<thead><tr>
|
||
|
|
<th>
|
||
|
|
<p>
|
||
|
|
Name
|
||
|
|
</p>
|
||
|
|
</th>
|
||
|
|
<th>
|
||
|
|
<p>
|
||
|
|
Description
|
||
|
|
</p>
|
||
|
|
</th>
|
||
|
|
</tr></thead>
|
||
|
|
<tbody>
|
||
|
|
<tr>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
<a class="link" href="use_future_t/get_allocator.html" title="use_future_t::get_allocator"><span class="bold"><strong>get_allocator</strong></span></a>
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
Obtain allocator.
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
<a class="link" href="use_future_t/operator_lp__rp_.html" title="use_future_t::operator()"><span class="bold"><strong>operator()</strong></span></a>
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
Wrap a function object in a packaged task.
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
<a class="link" href="use_future_t/operator_lb__rb_.html" title="use_future_t::operator[]"><span class="bold"><strong>operator[]</strong></span></a>
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
(Deprecated: Use rebind().) Specify an alternate allocator.
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
<a class="link" href="use_future_t/rebind.html" title="use_future_t::rebind"><span class="bold"><strong>rebind</strong></span></a>
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
Specify an alternate allocator.
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
<a class="link" href="use_future_t/use_future_t.html" title="use_future_t::use_future_t"><span class="bold"><strong>use_future_t</strong></span></a> <span class="silver">[constructor]</span>
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
<td>
|
||
|
|
<p>
|
||
|
|
Construct using default-constructed allocator. <br> <span class="silver"> —</span><br> Construct
|
||
|
|
using specified allocator.
|
||
|
|
</p>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
</tbody>
|
||
|
|
</table></div>
|
||
|
|
<p>
|
||
|
|
The <a class="link" href="use_future_t.html" title="use_future_t"><code class="computeroutput"><span class="identifier">use_future_t</span></code></a>
|
||
|
|
class is a completion token type that is used to indicate that an asynchronous
|
||
|
|
operation should return a std::future object. A <a class="link" href="use_future_t.html" title="use_future_t"><code class="computeroutput"><span class="identifier">use_future_t</span></code></a> object may be passed
|
||
|
|
as a completion token to an asynchronous operation, typically using the special
|
||
|
|
value <code class="computeroutput"><span class="identifier">asio</span><span class="special">::</span><span class="identifier">use_future</span></code>. For example:
|
||
|
|
</p>
|
||
|
|
<pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">future</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span><span class="special">></span> <span class="identifier">my_future</span>
|
||
|
|
<span class="special">=</span> <span class="identifier">my_socket</span><span class="special">.</span><span class="identifier">async_read_some</span><span class="special">(</span><span class="identifier">my_buffer</span><span class="special">,</span> <span class="identifier">asio</span><span class="special">::</span><span class="identifier">use_future</span><span class="special">);</span>
|
||
|
|
</pre>
|
||
|
|
<p>
|
||
|
|
The initiating function (async_read_some in the above example) returns a
|
||
|
|
future that will receive the result of the operation. If the operation completes
|
||
|
|
with an <a class="link" href="error_code.html" title="error_code"><code class="computeroutput"><span class="identifier">error_code</span></code></a>
|
||
|
|
indicating failure, it is converted into a <a class="link" href="system_error.html" title="system_error"><code class="computeroutput"><span class="identifier">system_error</span></code></a> and passed back to
|
||
|
|
the caller via the future.
|
||
|
|
</p>
|
||
|
|
<h5>
|
||
|
|
<a name="asio.reference.use_future_t.h2"></a>
|
||
|
|
<span><a name="asio.reference.use_future_t.requirements"></a></span><a class="link" href="use_future_t.html#asio.reference.use_future_t.requirements">Requirements</a>
|
||
|
|
</h5>
|
||
|
|
<p>
|
||
|
|
<span class="emphasis"><em>Header: </em></span><code class="literal">asio/use_future.hpp</code>
|
||
|
|
</p>
|
||
|
|
<p>
|
||
|
|
<span class="emphasis"><em>Convenience header: </em></span><code class="literal">asio.hpp</code>
|
||
|
|
</p>
|
||
|
|
</div>
|
||
|
|
<div class="copyright-footer">Copyright © 2003-2023 Christopher M. Kohlhoff<p>
|
||
|
|
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
||
|
|
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
|
||
|
|
</p>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<div class="spirit-nav">
|
||
|
|
<a accesskey="p" href="use_future.html"><img src="../../prev.png" alt="Prev"></a><a accesskey="u" href="../reference.html"><img src="../../up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../home.png" alt="Home"></a><a accesskey="n" href="use_future_t/allocator_type.html"><img src="../../next.png" alt="Next"></a>
|
||
|
|
</div>
|
||
|
|
</body>
|
||
|
|
</html>
|