1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>http::async_write_header</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="../../index.html" title="Chapter 1. Boost.Beast"> 8<link rel="up" href="../ref.html" title="This Page Intentionally Left Blank 2/2"> 9<link rel="prev" href="boost__beast__http__write_header/overload2.html" title="http::write_header (2 of 2 overloads)"> 10<link rel="next" href="boost__beast__http__write.html" title="http::write"> 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="boost__beast__http__write_header/overload2.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../ref.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="boost__beast__http__write.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="beast.ref.boost__beast__http__async_write_header"></a><a class="link" href="boost__beast__http__async_write_header.html" title="http::async_write_header">http::async_write_header</a> 28</h4></div></div></div> 29<p> 30 <a class="indexterm" name="idm46057504597024"></a> 31 </p> 32<p> 33 Write a header to a stream asynchronously using a serializer. 34 </p> 35<h5> 36<a name="beast.ref.boost__beast__http__async_write_header.h0"></a> 37 <span class="phrase"><a name="beast.ref.boost__beast__http__async_write_header.synopsis"></a></span><a class="link" href="boost__beast__http__async_write_header.html#beast.ref.boost__beast__http__async_write_header.synopsis">Synopsis</a> 38 </h5> 39<p> 40 Defined in header <code class="literal"><<a href="../../../../../../boost/beast/http/write.hpp" target="_top">boost/beast/http/write.hpp</a>></code> 41 </p> 42<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> 43 <span class="keyword">class</span> <a href="../../../../../../doc/html/boost_asio/reference/AsyncWriteStream.html" target="_top"><span class="emphasis"><em>AsyncWriteStream</em></span></a><span class="special">,</span> 44 <span class="keyword">bool</span> <span class="identifier">isRequest</span><span class="special">,</span> 45 <span class="keyword">class</span> <a class="link" href="../concepts/Body.html" title="Body"><span class="emphasis"><em>Body</em></span></a><span class="special">,</span> 46 <span class="keyword">class</span> <a class="link" href="../concepts/Fields.html" title="Fields"><span class="emphasis"><em>Fields</em></span></a><span class="special">,</span> 47 <span class="keyword">class</span> <a href="../../../../../../doc/html/boost_asio/reference/WriteHandler.html" target="_top"><span class="emphasis"><em>WriteHandler</em></span></a> <span class="special">=</span> <span class="identifier">net</span><span class="special">::</span><span class="identifier">default_completion_token_t</span><span class="special"><</span> <span class="identifier">executor_type</span><span class="special"><</span><span class="identifier">AsyncWriteStream</span><span class="special">>>></span> 48<a href="../../../../../../doc/html/boost_asio/reference/asynchronous_operations.html#boost_asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type" target="_top"><span class="emphasis"><em>DEDUCED</em></span></a> 49<span class="identifier">async_write_header</span><span class="special">(</span> 50 <span class="identifier">AsyncWriteStream</span><span class="special">&</span> <span class="identifier">stream</span><span class="special">,</span> 51 <span class="identifier">serializer</span><span class="special"><</span> <span class="identifier">isRequest</span><span class="special">,</span> <span class="identifier">Body</span><span class="special">,</span> <span class="identifier">Fields</span> <span class="special">>&</span> <span class="identifier">sr</span><span class="special">,</span> 52 <span class="identifier">WriteHandler</span><span class="special">&&</span> <span class="identifier">handler</span> <span class="special">=</span> <span class="identifier">net</span><span class="special">::</span><span class="identifier">default_completion_token_t</span><span class="special"><</span> <a class="link" href="boost__beast__executor_type.html" title="executor_type">executor_type</a><span class="special"><</span> <span class="identifier">AsyncWriteStream</span> <span class="special">>>{});</span> 53</pre> 54<h5> 55<a name="beast.ref.boost__beast__http__async_write_header.h1"></a> 56 <span class="phrase"><a name="beast.ref.boost__beast__http__async_write_header.description"></a></span><a class="link" href="boost__beast__http__async_write_header.html#beast.ref.boost__beast__http__async_write_header.description">Description</a> 57 </h5> 58<p> 59 This function is used to write a header to a stream asynchronously using 60 a caller-provided HTTP/1 serializer. The function call always returns immediately. 61 The asynchronous operation will continue until one of the following conditions 62 is true: 63 </p> 64<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 65<li class="listitem"> 66 The function <a class="link" href="boost__beast__http__serializer/is_header_done.html" title="http::serializer::is_header_done"><code class="computeroutput"><span class="identifier">serializer</span><span class="special">::</span><span class="identifier">is_header_done</span></code></a> returns <code class="computeroutput"><span class="keyword">true</span></code> 67 </li> 68<li class="listitem"> 69 An error occurs. 70 </li> 71</ul></div> 72<p> 73 This operation is implemented in terms of zero or more calls to the stream's 74 <code class="computeroutput"><span class="identifier">async_write_some</span></code> function, 75 and is known as a <span class="emphasis"><em>composed operation</em></span>. The program must 76 ensure that the stream performs no other writes until this operation completes. 77 </p> 78<h5> 79<a name="beast.ref.boost__beast__http__async_write_header.h2"></a> 80 <span class="phrase"><a name="beast.ref.boost__beast__http__async_write_header.parameters"></a></span><a class="link" href="boost__beast__http__async_write_header.html#beast.ref.boost__beast__http__async_write_header.parameters">Parameters</a> 81 </h5> 82<div class="informaltable"><table class="table"> 83<colgroup> 84<col> 85<col> 86</colgroup> 87<thead><tr> 88<th> 89 <p> 90 Name 91 </p> 92 </th> 93<th> 94 <p> 95 Description 96 </p> 97 </th> 98</tr></thead> 99<tbody> 100<tr> 101<td> 102 <p> 103 <code class="computeroutput"><span class="identifier">stream</span></code> 104 </p> 105 </td> 106<td> 107 <p> 108 The stream to which the data is to be written. The type must support 109 the <span class="emphasis"><em>AsyncWriteStream</em></span> concept. 110 </p> 111 </td> 112</tr> 113<tr> 114<td> 115 <p> 116 <code class="computeroutput"><span class="identifier">sr</span></code> 117 </p> 118 </td> 119<td> 120 <p> 121 The serializer to use. The object must remain valid at least until 122 the handler is called; ownership is not transferred. 123 </p> 124 </td> 125</tr> 126<tr> 127<td> 128 <p> 129 <code class="computeroutput"><span class="identifier">handler</span></code> 130 </p> 131 </td> 132<td> 133 <p> 134 The completion handler to invoke when the operation completes. 135 The implementation takes ownership of the handler by performing 136 a decay-copy. The equivalent function signature of the handler 137 must be: 138 </p> 139<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span> 140 <span class="identifier">error_code</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">error</span><span class="special">,</span> <span class="comment">// result of operation</span> 141 <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">bytes_transferred</span> <span class="comment">// the number of bytes written to the stream</span> 142<span class="special">);</span> 143</pre> 144 <p> 145 Regardless of whether the asynchronous operation completes immediately 146 or not, the handler will not be invoked from within this function. 147 Invocation of the handler will be performed in a manner equivalent 148 to using <a class="link" href="boost__beast__http__verb.html" title="http::verb"><code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">post</span></code></a>. 149 </p> 150 </td> 151</tr> 152</tbody> 153</table></div> 154<h5> 155<a name="beast.ref.boost__beast__http__async_write_header.h3"></a> 156 <span class="phrase"><a name="beast.ref.boost__beast__http__async_write_header.remarks"></a></span><a class="link" href="boost__beast__http__async_write_header.html#beast.ref.boost__beast__http__async_write_header.remarks">Remarks</a> 157 </h5> 158<p> 159 The implementation will call <a class="link" href="boost__beast__http__serializer/split/overload1.html" title="http::serializer::split (1 of 2 overloads)"><code class="computeroutput"><span class="identifier">serializer</span><span class="special">::</span><span class="identifier">split</span></code></a> with the value <code class="computeroutput"><span class="keyword">true</span></code> on the serializer passed in. 160 </p> 161<h5> 162<a name="beast.ref.boost__beast__http__async_write_header.h4"></a> 163 <span class="phrase"><a name="beast.ref.boost__beast__http__async_write_header.see_also"></a></span><a class="link" href="boost__beast__http__async_write_header.html#beast.ref.boost__beast__http__async_write_header.see_also">See Also</a> 164 </h5> 165<p> 166 <a class="link" href="boost__beast__http__serializer.html" title="http::serializer"><code class="computeroutput"><span class="identifier">serializer</span></code></a> 167 </p> 168</div> 169<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 170<td align="left"></td> 171<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie 172 Falco<p> 173 Distributed under the Boost Software License, Version 1.0. (See accompanying 174 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>) 175 </p> 176</div></td> 177</tr></table> 178<hr> 179<div class="spirit-nav"> 180<a accesskey="p" href="boost__beast__http__write_header/overload2.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../ref.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="boost__beast__http__write.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 181</div> 182</body> 183</html> 184
