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| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="boost_asio.reference.high_resolution_timer"></a><a class="link" href="high_resolution_timer.html" title="high_resolution_timer">high_resolution_timer</a> |
| </h3></div></div></div> |
| <p> |
| <a class="indexterm" name="idp141312992"></a> |
| Typedef for a timer based on the high resolution clock. |
| </p> |
| <pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">basic_waitable_timer</span><span class="special"><</span> <span class="identifier">chrono</span><span class="special">::</span><span class="identifier">high_resolution_clock</span> <span class="special">></span> <span class="identifier">high_resolution_timer</span><span class="special">;</span> |
| </pre> |
| <h5> |
| <a name="boost_asio.reference.high_resolution_timer.h0"></a> |
| <span class="phrase"><a name="boost_asio.reference.high_resolution_timer.types"></a></span><a class="link" href="high_resolution_timer.html#boost_asio.reference.high_resolution_timer.types">Types</a> |
| </h5> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Name |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/clock_type.html" title="basic_waitable_timer::clock_type"><span class="bold"><strong>clock_type</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The clock type. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/duration.html" title="basic_waitable_timer::duration"><span class="bold"><strong>duration</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The duration type of the clock. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/implementation_type.html" title="basic_waitable_timer::implementation_type"><span class="bold"><strong>implementation_type</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The underlying implementation type of I/O object. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/service_type.html" title="basic_waitable_timer::service_type"><span class="bold"><strong>service_type</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The type of the service that will be used to provide I/O operations. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/time_point.html" title="basic_waitable_timer::time_point"><span class="bold"><strong>time_point</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The time point type of the clock. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/traits_type.html" title="basic_waitable_timer::traits_type"><span class="bold"><strong>traits_type</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The wait traits type. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <h5> |
| <a name="boost_asio.reference.high_resolution_timer.h1"></a> |
| <span class="phrase"><a name="boost_asio.reference.high_resolution_timer.member_functions"></a></span><a class="link" href="high_resolution_timer.html#boost_asio.reference.high_resolution_timer.member_functions">Member |
| Functions</a> |
| </h5> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Name |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/async_wait.html" title="basic_waitable_timer::async_wait"><span class="bold"><strong>async_wait</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Start an asynchronous wait on the timer. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/basic_waitable_timer.html" title="basic_waitable_timer::basic_waitable_timer"><span class="bold"><strong>basic_waitable_timer</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Constructor. |
| </p> |
| <p> |
| Constructor to set a particular expiry time as an absolute time. |
| </p> |
| <p> |
| Constructor to set a particular expiry time relative to now. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/cancel.html" title="basic_waitable_timer::cancel"><span class="bold"><strong>cancel</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Cancel any asynchronous operations that are waiting on the timer. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/cancel_one.html" title="basic_waitable_timer::cancel_one"><span class="bold"><strong>cancel_one</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Cancels one asynchronous operation that is waiting on the timer. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/expires_at.html" title="basic_waitable_timer::expires_at"><span class="bold"><strong>expires_at</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Get the timer's expiry time as an absolute time. |
| </p> |
| <p> |
| Set the timer's expiry time as an absolute time. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/expires_from_now.html" title="basic_waitable_timer::expires_from_now"><span class="bold"><strong>expires_from_now</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Get the timer's expiry time relative to now. |
| </p> |
| <p> |
| Set the timer's expiry time relative to now. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/get_io_service.html" title="basic_waitable_timer::get_io_service"><span class="bold"><strong>get_io_service</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Get the io_service associated with the object. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/wait.html" title="basic_waitable_timer::wait"><span class="bold"><strong>wait</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Perform a blocking wait on the timer. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <h5> |
| <a name="boost_asio.reference.high_resolution_timer.h2"></a> |
| <span class="phrase"><a name="boost_asio.reference.high_resolution_timer.protected_member_functions"></a></span><a class="link" href="high_resolution_timer.html#boost_asio.reference.high_resolution_timer.protected_member_functions">Protected |
| Member Functions</a> |
| </h5> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Name |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/get_implementation.html" title="basic_waitable_timer::get_implementation"><span class="bold"><strong>get_implementation</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Get the underlying implementation of the I/O object. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/get_service.html" title="basic_waitable_timer::get_service"><span class="bold"><strong>get_service</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Get the service associated with the I/O object. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <h5> |
| <a name="boost_asio.reference.high_resolution_timer.h3"></a> |
| <span class="phrase"><a name="boost_asio.reference.high_resolution_timer.protected_data_members"></a></span><a class="link" href="high_resolution_timer.html#boost_asio.reference.high_resolution_timer.protected_data_members">Protected |
| Data Members</a> |
| </h5> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Name |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/implementation.html" title="basic_waitable_timer::implementation"><span class="bold"><strong>implementation</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| (Deprecated: Use get_implementation().) The underlying implementation |
| of the I/O object. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_waitable_timer/service.html" title="basic_waitable_timer::service"><span class="bold"><strong>service</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| (Deprecated: Use get_service().) The service associated with the |
| I/O object. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <p> |
| The <a class="link" href="basic_waitable_timer.html" title="basic_waitable_timer"><code class="computeroutput"><span class="identifier">basic_waitable_timer</span></code></a> class template |
| provides the ability to perform a blocking or asynchronous wait for a timer |
| to expire. |
| </p> |
| <p> |
| A waitable timer is always in one of two states: "expired" or "not |
| expired". If the <code class="computeroutput"><span class="identifier">wait</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">async_wait</span><span class="special">()</span></code> function is called on an expired timer, |
| the wait operation will complete immediately. |
| </p> |
| <p> |
| Most applications will use one of the <a class="link" href="steady_timer.html" title="steady_timer"><code class="computeroutput"><span class="identifier">steady_timer</span></code></a>, <a class="link" href="system_timer.html" title="system_timer"><code class="computeroutput"><span class="identifier">system_timer</span></code></a> or <a class="link" href="high_resolution_timer.html" title="high_resolution_timer"><code class="computeroutput"><span class="identifier">high_resolution_timer</span></code></a> typedefs. |
| </p> |
| <h5> |
| <a name="boost_asio.reference.high_resolution_timer.h4"></a> |
| <span class="phrase"><a name="boost_asio.reference.high_resolution_timer.remarks"></a></span><a class="link" href="high_resolution_timer.html#boost_asio.reference.high_resolution_timer.remarks">Remarks</a> |
| </h5> |
| <p> |
| This waitable timer functionality is for use with the C++11 standard library's |
| <code class="computeroutput"><span class="special"><</span><span class="identifier">chrono</span><span class="special">></span></code> facility, or with the Boost.Chrono library. |
| </p> |
| <h5> |
| <a name="boost_asio.reference.high_resolution_timer.h5"></a> |
| <span class="phrase"><a name="boost_asio.reference.high_resolution_timer.thread_safety"></a></span><a class="link" href="high_resolution_timer.html#boost_asio.reference.high_resolution_timer.thread_safety">Thread |
| Safety</a> |
| </h5> |
| <p> |
| <span class="emphasis"><em>Distinct</em></span> <span class="emphasis"><em>objects:</em></span> Safe. |
| </p> |
| <p> |
| <span class="emphasis"><em>Shared</em></span> <span class="emphasis"><em>objects:</em></span> Unsafe. |
| </p> |
| <h5> |
| <a name="boost_asio.reference.high_resolution_timer.h6"></a> |
| <span class="phrase"><a name="boost_asio.reference.high_resolution_timer.examples"></a></span><a class="link" href="high_resolution_timer.html#boost_asio.reference.high_resolution_timer.examples">Examples</a> |
| </h5> |
| <p> |
| Performing a blocking wait (C++11): |
| </p> |
| <pre class="programlisting"><span class="comment">// Construct a timer without setting an expiry time.</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">steady_timer</span> <span class="identifier">timer</span><span class="special">(</span><span class="identifier">io_service</span><span class="special">);</span> |
| |
| <span class="comment">// Set an expiry time relative to now.</span> |
| <span class="identifier">timer</span><span class="special">.</span><span class="identifier">expires_from_now</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">seconds</span><span class="special">(</span><span class="number">5</span><span class="special">));</span> |
| |
| <span class="comment">// Wait for the timer to expire.</span> |
| <span class="identifier">timer</span><span class="special">.</span><span class="identifier">wait</span><span class="special">();</span> |
| </pre> |
| <p> |
| Performing an asynchronous wait (C++11): |
| </p> |
| <pre class="programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&</span> <span class="identifier">error</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">error</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="comment">// Timer expired.</span> |
| <span class="special">}</span> |
| <span class="special">}</span> |
| |
| <span class="special">...</span> |
| |
| <span class="comment">// Construct a timer with an absolute expiry time.</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">steady_timer</span> <span class="identifier">timer</span><span class="special">(</span><span class="identifier">io_service</span><span class="special">,</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">steady_clock</span><span class="special">::</span><span class="identifier">now</span><span class="special">()</span> <span class="special">+</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">seconds</span><span class="special">(</span><span class="number">60</span><span class="special">));</span> |
| |
| <span class="comment">// Start an asynchronous wait.</span> |
| <span class="identifier">timer</span><span class="special">.</span><span class="identifier">async_wait</span><span class="special">(</span><span class="identifier">handler</span><span class="special">);</span> |
| </pre> |
| <h5> |
| <a name="boost_asio.reference.high_resolution_timer.h7"></a> |
| <span class="phrase"><a name="boost_asio.reference.high_resolution_timer.changing_an_active_waitable_timer_s_expiry_time"></a></span><a class="link" href="high_resolution_timer.html#boost_asio.reference.high_resolution_timer.changing_an_active_waitable_timer_s_expiry_time">Changing |
| an active waitable timer's expiry time</a> |
| </h5> |
| <p> |
| Changing the expiry time of a timer while there are pending asynchronous |
| waits causes those wait operations to be cancelled. To ensure that the action |
| associated with the timer is performed only once, use something like this: |
| used: |
| </p> |
| <pre class="programlisting"><span class="keyword">void</span> <span class="identifier">on_some_event</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="keyword">if</span> <span class="special">(</span><span class="identifier">my_timer</span><span class="special">.</span><span class="identifier">expires_from_now</span><span class="special">(</span><span class="identifier">seconds</span><span class="special">(</span><span class="number">5</span><span class="special">))</span> <span class="special">></span> <span class="number">0</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="comment">// We managed to cancel the timer. Start new asynchronous wait.</span> |
| <span class="identifier">my_timer</span><span class="special">.</span><span class="identifier">async_wait</span><span class="special">(</span><span class="identifier">on_timeout</span><span class="special">);</span> |
| <span class="special">}</span> |
| <span class="keyword">else</span> |
| <span class="special">{</span> |
| <span class="comment">// Too late, timer has already expired!</span> |
| <span class="special">}</span> |
| <span class="special">}</span> |
| |
| <span class="keyword">void</span> <span class="identifier">on_timeout</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&</span> <span class="identifier">e</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="keyword">if</span> <span class="special">(</span><span class="identifier">e</span> <span class="special">!=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">error</span><span class="special">::</span><span class="identifier">operation_aborted</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="comment">// Timer was not cancelled, take necessary action.</span> |
| <span class="special">}</span> |
| <span class="special">}</span> |
| </pre> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| The <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">basic_waitable_timer</span><span class="special">::</span><span class="identifier">expires_from_now</span><span class="special">()</span></code> |
| function cancels any pending asynchronous waits, and returns the number |
| of asynchronous waits that were cancelled. If it returns 0 then you were |
| too late and the wait handler has already been executed, or will soon |
| be executed. If it returns 1 then the wait handler was successfully cancelled. |
| </li> |
| <li class="listitem"> |
| If a wait handler is cancelled, the boost::system::error_code passed |
| to it contains the value <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">error</span><span class="special">::</span><span class="identifier">operation_aborted</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| This typedef uses the C++11 <code class="computeroutput"><span class="special"><</span><span class="identifier">chrono</span><span class="special">></span></code> |
| standard library facility, if available. Otherwise, it may use the Boost.Chrono |
| library. To explicitly utilise Boost.Chrono, use the <a class="link" href="basic_waitable_timer.html" title="basic_waitable_timer"><code class="computeroutput"><span class="identifier">basic_waitable_timer</span></code></a> template directly: |
| </p> |
| <pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">basic_waitable_timer</span><span class="special"><</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">chrono</span><span class="special">::</span><span class="identifier">high_resolution_clock</span><span class="special">></span> <span class="identifier">timer</span><span class="special">;</span> |
| </pre> |
| <h5> |
| <a name="boost_asio.reference.high_resolution_timer.h8"></a> |
| <span class="phrase"><a name="boost_asio.reference.high_resolution_timer.requirements"></a></span><a class="link" href="high_resolution_timer.html#boost_asio.reference.high_resolution_timer.requirements">Requirements</a> |
| </h5> |
| <p> |
| <span class="emphasis"><em>Header: </em></span><code class="literal">boost/asio/high_resolution_timer.hpp</code> |
| </p> |
| <p> |
| <span class="emphasis"><em>Convenience header: </em></span>None |
| </p> |
| </div> |
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| <td align="right"><div class="copyright-footer">Copyright © 2003-2015 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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