72 lines
2.9 KiB
HTML
72 lines
2.9 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<meta name="Copyright" content="Copyright (c) 2006 by IBM Corporation">
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<title>Time APIs</title>
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</head>
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<body>
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<h2>Time APIs</h2>
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<p>The Time APIs include two
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sets of APIs:</p>
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<ul>
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<li><a href="unix10a.htm">System Clock APIs</a></li>
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<li><a href="unix10b.htm">Software Clock APIs</a></li>
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</ul>
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<p>Both the System Clock and Software Clock APIs use a timeval structure that
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is the number of seconds and microseconds since 1 January 1970, 00:00:00
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Universal Coordinated Time (UTC).</p>
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<p>The System Clock APIs allow you to work with the system clock. The system
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clock is a system facility that maintains the time of the system. The <strong>
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gettimeofday()</strong> and <strong>ftime()</strong> APIs get the current time
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from the system clock. The <strong>adjtime()</strong> and <strong>
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settimeofday()</strong> APIs set the system clock. See the <a href=
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"../rzati/rzatikickoff.htm">Time Management</a> topic for more information
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about the system clock.</p>
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<p>The Software Clock APIs allow you to work with the software clock. The
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software clock is a system facility that maintains a time that is independent
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from the system clock. The <strong>Qp0zGetTimeofDay()</strong> API gets the
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current time from the software clock. The <strong>Qp0zAdjTime()</strong> and
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<strong>Qp0zSetTimeofDay()</strong> APIs set the software clock. In previous
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releases, the software clock was the only way to get a UTC time in seconds and
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microseconds. System components do not base their timestamps on the
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software clock, but use the system clock instead. The software clock will be
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removed in a future release and its use is discouraged.</p>
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<hr>
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<center>
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<table cellpadding="2" cellspacing="2">
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<tr align="center">
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<td valign="middle" align="center"><a href="#Top_Of_Page">Top</a> | <a href=
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"unix.htm">UNIX-Type APIs</a> | <a href="aplist.htm">APIs by category</a></td>
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</tr>
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</table>
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</center>
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</body>
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</html>
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