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<div class="titlepage"><div><div><h4 class="title">
<a name="asio.overview.cpp2011.chrono"></a><a class="link" href="chrono.html" title="Chrono">Chrono</a>
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<p>
Asio provides timers based on the <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span></code>
facilities via the <a class="link" href="../../reference/basic_waitable_timer.html" title="basic_waitable_timer">basic_waitable_timer</a>
class template. The typedefs <a class="link" href="../../reference/system_timer.html" title="system_timer">system_timer</a>,
<a class="link" href="../../reference/steady_timer.html" title="steady_timer">steady_timer</a> and <a class="link" href="../../reference/high_resolution_timer.html" title="high_resolution_timer">high_resolution_timer</a>
utilise the standard clocks <code class="computeroutput"><span class="identifier">system_clock</span></code>,
<code class="computeroutput"><span class="identifier">steady_clock</span></code> and <code class="computeroutput"><span class="identifier">high_resolution_clock</span></code> respectively.
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<p>
Support for the <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span></code> facilities is automatically enabled
for <code class="literal">g++</code> 4.6 and later, when the <code class="literal">-std=c++0x</code>
or <code class="literal">-std=gnu++0x</code> compiler options are used. (Note that,
for <code class="literal">g++</code>, the draft-standard <code class="computeroutput"><span class="identifier">monotonic_clock</span></code>
is used in place of <code class="computeroutput"><span class="identifier">steady_clock</span></code>.)
Support may be disabled by defining <code class="computeroutput"><span class="identifier">ASIO_DISABLE_STD_CHRONO</span></code>,
or explicitly enabled for other compilers by defining <code class="computeroutput"><span class="identifier">ASIO_HAS_STD_CHRONO</span></code>.
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<p>
When standard <code class="computeroutput"><span class="identifier">chrono</span></code> is
unavailable, Asio will otherwise use the Boost.Chrono library. The <a class="link" href="../../reference/basic_waitable_timer.html" title="basic_waitable_timer">basic_waitable_timer</a>
class template may be used with either.
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<div class="copyright-footer">Copyright © 2003-2023 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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