1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>co_spawn (1 of 6 overloads)</title> 5<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../boost_asio.html" title="Boost.Asio"> 8<link rel="up" href="../co_spawn.html" title="co_spawn"> 9<link rel="prev" href="../co_spawn.html" title="co_spawn"> 10<link rel="next" href="overload2.html" title="co_spawn (2 of 6 overloads)"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="../co_spawn.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../co_spawn.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../boost_asio.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="overload2.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="boost_asio.reference.co_spawn.overload1"></a><a class="link" href="overload1.html" title="co_spawn (1 of 6 overloads)">co_spawn (1 28 of 6 overloads)</a> 29</h4></div></div></div> 30<p> 31 Spawn a new coroutined-based thread of execution. 32 </p> 33<pre class="programlisting">template< 34 typename <a class="link" href="../Executor1.html" title="Executor requirements">Executor</a>, 35 typename T, 36 typename <a class="link" href="../Executor1.html" title="Executor requirements">AwaitableExecutor</a>, 37 typename CompletionToken = <a class="link" href="../asynchronous_operations.html#boost_asio.reference.asynchronous_operations.default_completion_tokens"><span class="emphasis"><em>DEFAULT</em></span></a>> 38<a class="link" href="../asynchronous_operations.html#boost_asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type"><span class="emphasis"><em>DEDUCED</em></span></a> co_spawn( 39 const Executor & ex, 40 awaitable< T, AwaitableExecutor > a, 41 CompletionToken && token = <a class="link" href="../asynchronous_operations.html#boost_asio.reference.asynchronous_operations.default_completion_tokens"><span class="emphasis"><em>DEFAULT</em></span></a>, 42 typename enable_if< (is_executor< Executor >::value||execution::is_executor< Executor >::value)&&is_convertible< Executor, AwaitableExecutor >::value >::type * = 0); 43</pre> 44<h6> 45<a name="boost_asio.reference.co_spawn.overload1.h0"></a> 46 <span class="phrase"><a name="boost_asio.reference.co_spawn.overload1.parameters"></a></span><a class="link" href="overload1.html#boost_asio.reference.co_spawn.overload1.parameters">Parameters</a> 47 </h6> 48<div class="variablelist"> 49<p class="title"><b></b></p> 50<dl class="variablelist"> 51<dt><span class="term">ex</span></dt> 52<dd><p> 53 The executor that will be used to schedule the new thread of execution. 54 </p></dd> 55<dt><span class="term">a</span></dt> 56<dd><p> 57 The <a class="link" href="../awaitable.html" title="awaitable"><code class="computeroutput">awaitable</code></a> 58 object that is the result of calling the coroutine's entry point 59 function. 60 </p></dd> 61<dt><span class="term">token</span></dt> 62<dd> 63<p> 64 The completion token that will handle the notification that the thread 65 of execution has completed. The function signature of the completion 66 handler must be: 67</p> 68<pre class="programlisting">void handler(std::exception_ptr, T); 69</pre> 70<p> 71 </p> 72</dd> 73</dl> 74</div> 75<h6> 76<a name="boost_asio.reference.co_spawn.overload1.h1"></a> 77 <span class="phrase"><a name="boost_asio.reference.co_spawn.overload1.example"></a></span><a class="link" href="overload1.html#boost_asio.reference.co_spawn.overload1.example">Example</a> 78 </h6> 79<pre class="programlisting">boost::asio::awaitable<std::size_t> echo(tcp::socket socket) 80{ 81 std::size_t bytes_transferred = 0; 82 83 try 84 { 85 char data[1024]; 86 for (;;) 87 { 88 std::size_t n = co_await socket.async_read_some( 89 boost::asio::buffer(data), boost::asio::use_awaitable); 90 91 co_await boost::asio::async_write(socket, 92 boost::asio::buffer(data, n), boost::asio::use_awaitable); 93 94 bytes_transferred += n; 95 } 96 } 97 catch (const std::exception&) 98 { 99 } 100 101 co_return bytes_transferred; 102} 103 104// ... 105 106boost::asio::co_spawn(my_executor, 107 echo(std::move(my_tcp_socket)), 108 [](std::exception_ptr e, std::size_t n) 109 { 110 std::cout << "transferred " << n << "\n"; 111 }); 112</pre> 113</div> 114<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 115<td align="left"></td> 116<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 117 Kohlhoff<p> 118 Distributed under the Boost Software License, Version 1.0. (See accompanying 119 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>) 120 </p> 121</div></td> 122</tr></table> 123<hr> 124<div class="spirit-nav"> 125<a accesskey="p" href="../co_spawn.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../co_spawn.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../boost_asio.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="overload2.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 126</div> 127</body> 128</html> 129
