1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Object HANDLEs</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="../windows.html" title="Windows-Specific Functionality"> 9<link rel="prev" href="random_access_handle.html" title="Random-Access HANDLEs"> 10<link rel="next" href="../ssl.html" title="SSL"> 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="random_access_handle.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../windows.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="../ssl.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.overview.windows.object_handle"></a><a class="link" href="object_handle.html" title="Object HANDLEs">Object HANDLEs</a> 28</h4></div></div></div> 29<p> 30 Boost.Asio provides Windows-specific classes that permit asynchronous wait 31 operations to be performed on HANDLEs to kernel objects of the following 32 types: 33 </p> 34<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 35<li class="listitem"> 36 Change notification 37 </li> 38<li class="listitem"> 39 Console input 40 </li> 41<li class="listitem"> 42 Event 43 </li> 44<li class="listitem"> 45 Memory resource notification 46 </li> 47<li class="listitem"> 48 Process 49 </li> 50<li class="listitem"> 51 Semaphore 52 </li> 53<li class="listitem"> 54 Thread 55 </li> 56<li class="listitem"> 57 Waitable timer 58 </li> 59</ul></div> 60<p> 61 For example, to perform asynchronous operations on an event, the following 62 object may be created: 63 </p> 64<pre class="programlisting">HANDLE handle = ::CreateEvent(...); 65windows::object_handle file(my_io_context, handle); 66</pre> 67<p> 68 The <code class="computeroutput">wait()</code> and <code class="computeroutput">async_wait()</code> member functions 69 may then be used to wait until the kernel object is signalled. 70 </p> 71<h6> 72<a name="boost_asio.overview.windows.object_handle.h0"></a> 73 <span class="phrase"><a name="boost_asio.overview.windows.object_handle.see_also"></a></span><a class="link" href="object_handle.html#boost_asio.overview.windows.object_handle.see_also">See Also</a> 74 </h6> 75<p> 76 <a class="link" href="../../reference/windows__object_handle.html" title="windows::object_handle">windows::object_handle</a>. 77 </p> 78<h6> 79<a name="boost_asio.overview.windows.object_handle.h1"></a> 80 <span class="phrase"><a name="boost_asio.overview.windows.object_handle.notes"></a></span><a class="link" href="object_handle.html#boost_asio.overview.windows.object_handle.notes">Notes</a> 81 </h6> 82<p> 83 Windows object <code class="computeroutput">HANDLE</code>s are only available at compile time 84 when targeting Windows. Programs may test for the macro <code class="computeroutput">BOOST_ASIO_HAS_WINDOWS_OBJECT_HANDLE</code> 85 to determine whether they are supported. 86 </p> 87</div> 88<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 89<td align="left"></td> 90<td align="right"><div class="copyright-footer">Copyright © 2003-2020 Christopher M. 91 Kohlhoff<p> 92 Distributed under the Boost Software License, Version 1.0. (See accompanying 93 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>) 94 </p> 95</div></td> 96</tr></table> 97<hr> 98<div class="spirit-nav"> 99<a accesskey="p" href="random_access_handle.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../windows.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="../ssl.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 100</div> 101</body> 102</html> 103