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| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="boost_asio.reference.TimerService"></a><a class="link" href="TimerService.html" title="Timer service requirements">Timer service requirements</a> |
| </h3></div></div></div> |
| <p> |
| A timer service must meet the requirements for an <a class="link" href="IoObjectService.html" title="I/O object service requirements">I/O |
| object service</a>, as well as the additional requirements listed below. |
| </p> |
| <p> |
| In the table below, <code class="computeroutput"><span class="identifier">X</span></code> denotes |
| a timer service class for time type <code class="computeroutput"><span class="identifier">Time</span></code> |
| and traits type <code class="computeroutput"><span class="identifier">TimeTraits</span></code>, |
| <code class="computeroutput"><span class="identifier">a</span></code> denotes a value of type |
| <code class="computeroutput"><span class="identifier">X</span></code>, <code class="computeroutput"><span class="identifier">b</span></code> |
| denotes a value of type <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">implementation_type</span></code>, |
| <code class="computeroutput"><span class="identifier">t</span></code> denotes a value of type |
| <code class="computeroutput"><span class="identifier">Time</span></code>, <code class="computeroutput"><span class="identifier">d</span></code> |
| denotes a value of type <code class="computeroutput"><span class="identifier">TimeTraits</span><span class="special">::</span><span class="identifier">duration_type</span></code>, |
| <code class="computeroutput"><span class="identifier">e</span></code> denotes a value of type |
| <code class="computeroutput"><span class="identifier">error_code</span></code>, and <code class="computeroutput"><span class="identifier">h</span></code> denotes a value meeting <a class="link" href="WaitHandler.html" title="Wait handler requirements"><code class="computeroutput"><span class="identifier">WaitHandler</span></code></a> requirements. |
| </p> |
| <div class="table"> |
| <a name="id865957"></a><p class="title"><b>Table 36. TimerService requirements</b></p> |
| <div class="table-contents"><table class="table" summary="TimerService requirements"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| expression |
| </p> |
| </th> |
| <th> |
| <p> |
| return type |
| </p> |
| </th> |
| <th> |
| <p> |
| assertion/note<br> pre/post-condition |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">destroy</span><span class="special">(</span><span class="identifier">b</span><span class="special">);</span></code> |
| </p> |
| </td> |
| <td> |
| </td> |
| <td> |
| <p> |
| From <a class="link" href="IoObjectService.html" title="I/O object service requirements">IoObjectService</a> |
| requirements. Implicitly cancels asynchronous wait operations, |
| as if by calling <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">cancel</span><span class="special">(</span><span class="identifier">b</span><span class="special">,</span> <span class="identifier">e</span><span class="special">)</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">a</span><span class="special">.</span><span class="identifier">cancel</span><span class="special">(</span><span class="identifier">b</span><span class="special">,</span> <span class="identifier">e</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">size_t</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Causes any outstanding asynchronous wait operations to complete |
| as soon as possible. Handlers for cancelled operations shall be |
| passed the error code <code class="computeroutput"><span class="identifier">error</span><span class="special">::</span><span class="identifier">operation_aborted</span></code>. |
| Sets <code class="computeroutput"><span class="identifier">e</span></code> to indicate |
| success or failure. Returns the number of operations that were |
| cancelled. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">expires_at</span><span class="special">(</span><span class="identifier">b</span><span class="special">);</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Time</span></code> |
| </p> |
| </td> |
| <td> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">a</span><span class="special">.</span><span class="identifier">expires_at</span><span class="special">(</span><span class="identifier">b</span><span class="special">,</span> <span class="identifier">t</span><span class="special">,</span> <span class="identifier">e</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">size_t</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Implicitly cancels asynchronous wait operations, as if by calling |
| <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">cancel</span><span class="special">(</span><span class="identifier">b</span><span class="special">,</span> |
| <span class="identifier">e</span><span class="special">)</span></code>. |
| Returns the number of operations that were cancelled.<br> post: |
| <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">expires_at</span><span class="special">(</span><span class="identifier">b</span><span class="special">)</span> |
| <span class="special">==</span> <span class="identifier">t</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">expires_from_now</span><span class="special">(</span><span class="identifier">b</span><span class="special">);</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">TimeTraits</span><span class="special">::</span><span class="identifier">duration_type</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Returns a value equivalent to <code class="computeroutput"><span class="identifier">TimeTraits</span><span class="special">::</span><span class="identifier">subtract</span><span class="special">(</span><span class="identifier">a</span><span class="special">.</span><span class="identifier">expires_at</span><span class="special">(</span><span class="identifier">b</span><span class="special">),</span> <span class="identifier">TimeTraits</span><span class="special">::</span><span class="identifier">now</span><span class="special">())</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">a</span><span class="special">.</span><span class="identifier">expires_from_now</span><span class="special">(</span><span class="identifier">b</span><span class="special">,</span> <span class="identifier">d</span><span class="special">,</span> <span class="identifier">e</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">size_t</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Equivalent to <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">expires_at</span><span class="special">(</span><span class="identifier">b</span><span class="special">,</span> <span class="identifier">TimeTraits</span><span class="special">::</span><span class="identifier">add</span><span class="special">(</span><span class="identifier">TimeTraits</span><span class="special">::</span><span class="identifier">now</span><span class="special">(),</span> <span class="identifier">d</span><span class="special">),</span> <span class="identifier">e</span><span class="special">)</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">a</span><span class="special">.</span><span class="identifier">wait</span><span class="special">(</span><span class="identifier">b</span><span class="special">,</span> <span class="identifier">e</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">error_code</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Sets <code class="computeroutput"><span class="identifier">e</span></code> to indicate |
| success or failure. Returns <code class="computeroutput"><span class="identifier">e</span></code>.<br> |
| post: <code class="computeroutput"><span class="special">!!</span><span class="identifier">e</span> |
| <span class="special">||</span> <span class="special">!</span><span class="identifier">TimeTraits</span><span class="special">::</span><span class="identifier">lt</span><span class="special">(</span><span class="identifier">TimeTraits</span><span class="special">::</span><span class="identifier">now</span><span class="special">(),</span> |
| <span class="identifier">a</span><span class="special">.</span><span class="identifier">expires_at</span><span class="special">(</span><span class="identifier">b</span><span class="special">))</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">a</span><span class="special">.</span><span class="identifier">async_wait</span><span class="special">(</span><span class="identifier">b</span><span class="special">,</span> <span class="identifier">h</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </td> |
| <td> |
| </td> |
| <td> |
| <p> |
| Initiates an asynchronous wait operation that is performed via |
| the <code class="computeroutput"><span class="identifier">io_service</span></code> |
| object <code class="computeroutput"><span class="identifier">a</span><span class="special">.</span><span class="identifier">io_service</span><span class="special">()</span></code> |
| and behaves according to <a class="link" href="asynchronous_operations.html" title="Requirements on asynchronous operations">asynchronous |
| operation</a> requirements.<br> <br> The handler shall be |
| posted for execution only if the condition <code class="computeroutput"><span class="special">!!</span><span class="identifier">ec</span> <span class="special">||</span> |
| <span class="special">!</span><span class="identifier">TimeTraits</span><span class="special">::</span><span class="identifier">lt</span><span class="special">(</span><span class="identifier">TimeTraits</span><span class="special">::</span><span class="identifier">now</span><span class="special">(),</span> <span class="identifier">a</span><span class="special">.</span><span class="identifier">expires_at</span><span class="special">(</span><span class="identifier">b</span><span class="special">))</span></code> holds, where <code class="computeroutput"><span class="identifier">ec</span></code> |
| is the error code to be passed to the handler. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <br class="table-break"> |
| </div> |
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| <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>) |
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