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<section id="date_time.posix_time"
  xmlns:xi="http://www.w3.org/2001/XInclude">
  <title>Posix Time</title>
  <bridgehead renderas="sect2">Posix Time System</bridgehead>
  <para>
    <link linkend="posix_intro">Introduction</link> -- 
    <link linkend="posix_ex">Usage Examples</link>
  </para>  
  
  <anchor id="posix_intro" />
  <bridgehead renderas="sect3">Introduction</bridgehead>
  <para>
    Defines a non-adjusted time system with nano-second/micro-second resolution and stable calculation properties.  The nano-second resolution option uses 96 bits of underlying storage for each ptime while the micro-second resolution uses 64 bits per ptime (see <link linkend="date_time.buildinfo">Build Options</link> for details). This time system uses the Gregorian calendar to implement the date portion of the time representation. 
  </para>

  <anchor id="posix_ex" />
  <bridgehead renderas="sect3">Usage Examples</bridgehead>
  <para>
    <informaltable frame="all">
      <tgroup cols="2">
	<thead>
	  <row>
	    <entry>Example</entry>
	    <entry>Description</entry>
	  </row>
	</thead>
	<tbody>
	  <row>
	    <entry><link linkend="date_time.examples.time_math">Time Math</link></entry>
	    <entry>A few simple calculations using ptime and time_durations.</entry>
	  </row>
	  <row>
	    <entry><link linkend="date_time.examples.print_hours">Print Hours</link></entry>
	    <entry>Retrieve time from clock, use a time_iterator.</entry>
	  </row>
	  <row>
	    <entry><link linkend="date_time.examples.local_utc_conversion">Local to UTC Conversion</link></entry>
	    <entry>Demonstrates a couple different ways to convert a local to UTC time including daylight savings rules.</entry>
	  </row>
	  <row>
	    <entry><link linkend="date_time.examples.time_periods">Time Periods</link></entry>
	    <entry>Some simple examples of intersection and display of time periods.</entry>
	  </row>
	</tbody>
      </tgroup>
    </informaltable>
  </para>
  
  <xi:include href="ptime_class.xml" />
  <xi:include href="time_duration.xml" />
  <xi:include href="time_period.xml" />
  <xi:include href="time_iterators.xml" />
  <!-- includes here -->
  
</section>

