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<p><a class="el" href="class_qwt_system_clock.html" title="QwtSystemClock provides high resolution clock time functions. ">QwtSystemClock</a> provides high resolution clock time functions.
<a href="class_qwt_system_clock.html#details">More...</a></p>
<p><code>#include <<a class="el" href="qwt__system__clock_8h_source.html">qwt_system_clock.h</a>></code></p>
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Public Member Functions</h2></td></tr>
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 </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_system_clock.html#a384e20d6049376575bf28306154854fd">QwtSystemClock</a> ()</td></tr>
<tr class="memdesc:a384e20d6049376575bf28306154854fd"><td class="mdescLeft"> </td><td class="mdescRight">Constructs a null clock object. <br /></td></tr>
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virtual </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_system_clock.html#a79a46a34a317543a08a8424a333b9ee3">~QwtSystemClock</a> ()</td></tr>
<tr class="memdesc:a79a46a34a317543a08a8424a333b9ee3"><td class="mdescLeft"> </td><td class="mdescRight">Destructor. <br /></td></tr>
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<tr class="memitem:a5432c09607488f9bb7e3d7592518efb1"><td class="memItemLeft" align="right" valign="top">bool </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_system_clock.html#a5432c09607488f9bb7e3d7592518efb1">isNull</a> () const </td></tr>
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<tr class="memitem:a3408bd55b49582f7847865aacc7beb37"><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_system_clock.html#a3408bd55b49582f7847865aacc7beb37">start</a> ()</td></tr>
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<tr class="memitem:a6be327dd133c1d7ecccfb95050eef7b9"><td class="memItemLeft" align="right" valign="top">double </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_system_clock.html#a6be327dd133c1d7ecccfb95050eef7b9">restart</a> ()</td></tr>
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<tr class="memitem:a0baae39a5a9d4f4e8bf3a8bd308a6dad"><td class="memItemLeft" align="right" valign="top">double </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_system_clock.html#a0baae39a5a9d4f4e8bf3a8bd308a6dad">elapsed</a> () const </td></tr>
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<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<div class="textblock"><p><a class="el" href="class_qwt_system_clock.html" title="QwtSystemClock provides high resolution clock time functions. ">QwtSystemClock</a> provides high resolution clock time functions. </p>
<p>Sometimes the resolution offered by QTime ( millisecond ) is not accurate enough for implementing time measurements ( f.e. sampling ). <a class="el" href="class_qwt_system_clock.html" title="QwtSystemClock provides high resolution clock time functions. ">QwtSystemClock</a> offers a subset of the QTime functionality using higher resolution timers ( if possible ).</p>
<p>Precision and time intervals are multiples of milliseconds (ms).</p>
<dl class="section note"><dt>Note</dt><dd>The implementation uses high-resolution performance counter on Windows, mach_absolute_time() on the Mac or POSIX timers on other systems. If none is available it falls back on QTimer. </dd></dl>
</div><h2 class="groupheader">Member Function Documentation</h2>
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<td class="memname">double QwtSystemClock::elapsed </td>
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<td> const</td>
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<dl class="section return"><dt>Returns</dt><dd>Number of milliseconds that have elapsed since the last time <a class="el" href="class_qwt_system_clock.html#a3408bd55b49582f7847865aacc7beb37">start()</a> or <a class="el" href="class_qwt_system_clock.html#a6be327dd133c1d7ecccfb95050eef7b9">restart()</a> was called or 0.0 for null clocks. </dd></dl>
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<td class="memname">bool QwtSystemClock::isNull </td>
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<dl class="section return"><dt>Returns</dt><dd>true if the clock has never been started. </dd></dl>
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<td class="memname">double QwtSystemClock::restart </td>
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<td class="paramname"></td><td>)</td>
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<p>Set the start time to the current time </p><dl class="section return"><dt>Returns</dt><dd>Time, that is elapsed since the previous start time. </dd></dl>
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<td class="memname">void QwtSystemClock::start </td>
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<p>Sets the start time to the current time. </p>
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