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| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="boost_asio.reference.deadline_timer"></a><a class="link" href="deadline_timer.html" title="deadline_timer">deadline_timer</a> |
| </h3></div></div></div> |
| <p> |
| <a class="indexterm" name="id1146033"></a> |
| Typedef for the typical usage of timer. Uses a UTC clock. |
| </p> |
| <pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">basic_deadline_timer</span><span class="special"><</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">posix_time</span><span class="special">::</span><span class="identifier">ptime</span> <span class="special">></span> <span class="identifier">deadline_timer</span><span class="special">;</span> |
| </pre> |
| <a name="boost_asio.reference.deadline_timer.types"></a><h5> |
| <a name="id1146109"></a> |
| <a class="link" href="deadline_timer.html#boost_asio.reference.deadline_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_deadline_timer/duration_type.html" title="basic_deadline_timer::duration_type"><span class="bold"><strong>duration_type</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The duration type. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_deadline_timer/implementation_type.html" title="basic_deadline_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_deadline_timer/service_type.html" title="basic_deadline_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_deadline_timer/time_type.html" title="basic_deadline_timer::time_type"><span class="bold"><strong>time_type</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The time type. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_deadline_timer/traits_type.html" title="basic_deadline_timer::traits_type"><span class="bold"><strong>traits_type</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The time traits type. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <a name="boost_asio.reference.deadline_timer.member_functions"></a><h5> |
| <a name="id1146309"></a> |
| <a class="link" href="deadline_timer.html#boost_asio.reference.deadline_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_deadline_timer/async_wait.html" title="basic_deadline_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_deadline_timer/basic_deadline_timer.html" title="basic_deadline_timer::basic_deadline_timer"><span class="bold"><strong>basic_deadline_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_deadline_timer/cancel.html" title="basic_deadline_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_deadline_timer/expires_at.html" title="basic_deadline_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_deadline_timer/expires_from_now.html" title="basic_deadline_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_deadline_timer/get_io_service.html" title="basic_deadline_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_deadline_timer/io_service.html" title="basic_deadline_timer::io_service"><span class="bold"><strong>io_service</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| (Deprecated: use get_io_service().) Get the io_service associated |
| with the object. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_deadline_timer/wait.html" title="basic_deadline_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> |
| <a name="boost_asio.reference.deadline_timer.protected_data_members"></a><h5> |
| <a name="id1146618"></a> |
| <a class="link" href="deadline_timer.html#boost_asio.reference.deadline_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_deadline_timer/implementation.html" title="basic_deadline_timer::implementation"><span class="bold"><strong>implementation</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The underlying implementation of the I/O object. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <a class="link" href="basic_deadline_timer/service.html" title="basic_deadline_timer::service"><span class="bold"><strong>service</strong></span></a> |
| </p> |
| </td> |
| <td> |
| <p> |
| The service associated with the I/O object. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <p> |
| The <a class="link" href="basic_deadline_timer.html" title="basic_deadline_timer"><code class="computeroutput"><span class="identifier">basic_deadline_timer</span></code></a> class template |
| provides the ability to perform a blocking or asynchronous wait for a timer |
| to expire. |
| </p> |
| <p> |
| A deadline 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 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">deadline_timer</span></code> |
| typedef. |
| </p> |
| <a name="boost_asio.reference.deadline_timer.thread_safety"></a><h5> |
| <a name="id1146822"></a> |
| <a class="link" href="deadline_timer.html#boost_asio.reference.deadline_timer.thread_safety">Thread |
| Safety</a> |
| </h5> |
| <p> |
| <span class="bold"><strong>Distinct</strong></span> <span class="bold"><strong>objects:</strong></span> |
| Safe. |
| </p> |
| <p> |
| <span class="bold"><strong>Shared</strong></span> <span class="bold"><strong>objects:</strong></span> |
| Unsafe. |
| </p> |
| <a name="boost_asio.reference.deadline_timer.examples"></a><h5> |
| <a name="id1146875"></a> |
| <a class="link" href="deadline_timer.html#boost_asio.reference.deadline_timer.examples">Examples</a> |
| </h5> |
| <p> |
| Performing a blocking wait: |
| </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">deadline_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">boost</span><span class="special">::</span><span class="identifier">posix_time</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: |
| </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">deadline_timer</span> <span class="identifier">timer</span><span class="special">(</span><span class="identifier">io_service</span><span class="special">,</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">posix_time</span><span class="special">::</span><span class="identifier">time_from_string</span><span class="special">(</span><span class="string">"2005-12-07 23:59:59.000"</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> |
| <a name="boost_asio.reference.deadline_timer.changing_an_active_deadline_timer_s_expiry_time"></a><h5> |
| <a name="id1147274"></a> |
| <a class="link" href="deadline_timer.html#boost_asio.reference.deadline_timer.changing_an_active_deadline_timer_s_expiry_time">Changing |
| an active deadline_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" 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_deadline_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> |
| <a name="boost_asio.reference.deadline_timer.requirements"></a><h5> |
| <a name="id1147709"></a> |
| <a class="link" href="deadline_timer.html#boost_asio.reference.deadline_timer.requirements">Requirements</a> |
| </h5> |
| <p> |
| <span class="bold"><strong>Header: </strong></span><code class="literal">boost/asio/deadline_timer.hpp</code> |
| </p> |
| <p> |
| <span class="bold"><strong>Convenience header: </strong></span><code class="literal">boost/asio.hpp</code> |
| </p> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2003 - 2010 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>) |
| </p> |
| </div></td> |
| </tr></table> |
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