1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>async_write (1 of 8 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="../async_write.html" title="async_write"> 9<link rel="prev" href="../async_write.html" title="async_write"> 10<link rel="next" href="overload2.html" title="async_write (2 of 8 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="../async_write.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../async_write.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.async_write.overload1"></a><a class="link" href="overload1.html" title="async_write (1 of 8 overloads)">async_write 28 (1 of 8 overloads)</a> 29</h4></div></div></div> 30<p> 31 Start an asynchronous operation to write all of the supplied data to a 32 stream. 33 </p> 34<pre class="programlisting">template< 35 typename <a class="link" href="../AsyncWriteStream.html" title="Buffer-oriented asynchronous write stream requirements">AsyncWriteStream</a>, 36 typename <a class="link" href="../ConstBufferSequence.html" title="Constant buffer sequence requirements">ConstBufferSequence</a>, 37 typename <a class="link" href="../WriteHandler.html" title="Write handler requirements">WriteHandler</a> = <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> async_write( 39 AsyncWriteStream & s, 40 const ConstBufferSequence & buffers, 41 WriteHandler && handler = <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_const_buffer_sequence< ConstBufferSequence >::value >::type * = 0); 43</pre> 44<p> 45 This function is used to asynchronously write a certain number of bytes 46 of data to a stream. The function call always returns immediately. The 47 asynchronous operation will continue until one of the following conditions 48 is true: 49 </p> 50<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 51<li class="listitem"> 52 All of the data in the supplied buffers has been written. That is, 53 the bytes transferred is equal to the sum of the buffer sizes. 54 </li> 55<li class="listitem"> 56 An error occurred. 57 </li> 58</ul></div> 59<p> 60 This operation is implemented in terms of zero or more calls to the stream's 61 async_write_some function, and is known as a <span class="emphasis"><em>composed operation</em></span>. 62 The program must ensure that the stream performs no other write operations 63 (such as async_write, the stream's async_write_some function, or any other 64 composed operations that perform writes) until this operation completes. 65 </p> 66<h6> 67<a name="boost_asio.reference.async_write.overload1.h0"></a> 68 <span class="phrase"><a name="boost_asio.reference.async_write.overload1.parameters"></a></span><a class="link" href="overload1.html#boost_asio.reference.async_write.overload1.parameters">Parameters</a> 69 </h6> 70<div class="variablelist"> 71<p class="title"><b></b></p> 72<dl class="variablelist"> 73<dt><span class="term">s</span></dt> 74<dd><p> 75 The stream to which the data is to be written. The type must support 76 the AsyncWriteStream concept. 77 </p></dd> 78<dt><span class="term">buffers</span></dt> 79<dd><p> 80 One or more buffers containing the data to be written. Although the 81 buffers object may be copied as necessary, ownership of the underlying 82 memory blocks is retained by the caller, which must guarantee that 83 they remain valid until the handler is called. 84 </p></dd> 85<dt><span class="term">handler</span></dt> 86<dd> 87<p> 88 The handler to be called when the write operation completes. Copies 89 will be made of the handler as required. The function signature of 90 the handler must be: 91</p> 92<pre class="programlisting">void handler( 93 const boost::system::error_code& error, // Result of operation. 94 95 std::size_t bytes_transferred // Number of bytes written from the 96 // buffers. If an error occurred, 97 // this will be less than the sum 98 // of the buffer sizes. 99); 100</pre> 101<p> 102 Regardless of whether the asynchronous operation completes immediately 103 or not, the handler will not be invoked from within this function. 104 On immediate completion, invocation of the handler will be performed 105 in a manner equivalent to using <a class="link" href="../post.html" title="post"><code class="computeroutput">post</code></a>. 106 </p> 107</dd> 108</dl> 109</div> 110<h6> 111<a name="boost_asio.reference.async_write.overload1.h1"></a> 112 <span class="phrase"><a name="boost_asio.reference.async_write.overload1.example"></a></span><a class="link" href="overload1.html#boost_asio.reference.async_write.overload1.example">Example</a> 113 </h6> 114<p> 115 To write a single data buffer use the <a class="link" href="../buffer.html" title="buffer"><code class="computeroutput">buffer</code></a> 116 function as follows: 117 </p> 118<pre class="programlisting">boost::asio::async_write(s, boost::asio::buffer(data, size), handler); 119</pre> 120<p> 121 See the <a class="link" href="../buffer.html" title="buffer"><code class="computeroutput">buffer</code></a> 122 documentation for information on writing multiple buffers in one go, and 123 how to use it with arrays, boost::array or std::vector. 124 </p> 125</div> 126<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 127<td align="left"></td> 128<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 129 Kohlhoff<p> 130 Distributed under the Boost Software License, Version 1.0. (See accompanying 131 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>) 132 </p> 133</div></td> 134</tr></table> 135<hr> 136<div class="spirit-nav"> 137<a accesskey="p" href="../async_write.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../async_write.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> 138</div> 139</body> 140</html> 141
