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<a href="#pub-methods">Public Member Functions</a> &#124;
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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 &lt;<a class="el" href="qwt__system__clock_8h_source.html">qwt_system_clock.h</a>&gt;</code></p>
<table class="memberdecls">
<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="pub-methods"></a>
Public Member Functions</h2></td></tr>
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&#160;</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">&#160;</td><td class="mdescRight">Constructs a null clock object. <br /></td></tr>
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virtual&#160;</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">&#160;</td><td class="mdescRight">Destructor. <br /></td></tr>
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<tr class="memitem:a7cde59f783269c5f3542ec93f450f5bd"><td class="memItemLeft" align="right" valign="top">bool&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_system_clock.html#a7cde59f783269c5f3542ec93f450f5bd">isNull</a> () const</td></tr>
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<tr class="memitem:a3408bd55b49582f7847865aacc7beb37"><td class="memItemLeft" align="right" valign="top">void&#160;</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&#160;</td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_system_clock.html#a6be327dd133c1d7ecccfb95050eef7b9">restart</a> ()</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>
<p>( <a class="el" href="class_qwt_system_clock.html" title="QwtSystemClock provides high resolution clock time functions.">QwtSystemClock</a> is obsolete since Qt 4.8 as QElapsedTimer offers the same precision )</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>
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<h2 class="memtitle"><span class="permalink"><a href="#a6d373715eb0fac098f2f02ce42a660c9">&#9670;&nbsp;</a></span>elapsed()</h2>

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          <td class="memname">double QwtSystemClock::elapsed </td>
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          <td class="paramname"></td><td>)</td>
          <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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<h2 class="memtitle"><span class="permalink"><a href="#a7cde59f783269c5f3542ec93f450f5bd">&#9670;&nbsp;</a></span>isNull()</h2>

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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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<h2 class="memtitle"><span class="permalink"><a href="#a6be327dd133c1d7ecccfb95050eef7b9">&#9670;&nbsp;</a></span>restart()</h2>

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          <td class="memname">double QwtSystemClock::restart </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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<h2 class="memtitle"><span class="permalink"><a href="#a3408bd55b49582f7847865aacc7beb37">&#9670;&nbsp;</a></span>start()</h2>

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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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