object_handle.html
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<title>Object HANDLEs</title>
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<div class="titlepage"><div><div><h4 class="title">
<a name="asio.overview.windows.object_handle"></a><a class="link" href="object_handle.html" title="Object HANDLEs">Object HANDLEs</a>
</h4></div></div></div>
<p>
Asio provides Windows-specific classes that permit asynchronous wait operations
to be performed on HANDLEs to kernel objects of the following types:
</p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
Change notification
</li>
<li class="listitem">
Console input
</li>
<li class="listitem">
Event
</li>
<li class="listitem">
Memory resource notification
</li>
<li class="listitem">
Process
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Semaphore
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Thread
</li>
<li class="listitem">
Waitable timer
</li>
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<p>
For example, to perform asynchronous operations on an event, the following
object may be created:
</p>
<pre class="programlisting">HANDLE handle = ::CreateEvent(...);
windows::object_handle file(my_io_context, handle);
</pre>
<p>
The <code class="computeroutput">wait()</code> and <code class="computeroutput">async_wait()</code> member functions
may then be used to wait until the kernel object is signalled.
</p>
<h6>
<a name="asio.overview.windows.object_handle.h0"></a>
<span><a name="asio.overview.windows.object_handle.see_also"></a></span><a class="link" href="object_handle.html#asio.overview.windows.object_handle.see_also">See
Also</a>
</h6>
<p>
<a class="link" href="../../reference/windows__object_handle.html" title="windows::object_handle">windows::object_handle</a>.
</p>
<h6>
<a name="asio.overview.windows.object_handle.h1"></a>
<span><a name="asio.overview.windows.object_handle.notes"></a></span><a class="link" href="object_handle.html#asio.overview.windows.object_handle.notes">Notes</a>
</h6>
<p>
Windows object <code class="computeroutput">HANDLE</code>s are only available at compile time
when targeting Windows. Programs may test for the macro <code class="computeroutput">ASIO_HAS_WINDOWS_OBJECT_HANDLE</code>
to determine whether they are supported.
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<td align="right"><div class="copyright-footer">Copyright © 2003-2020 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>)
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