xnu-792.21.3.tar.gz

[apple/xnu.git] / osfmk / man / clock_map_time.html

<h2>clock_map_time</h2>
<hr>
<p>
<strong>Function</strong> - Return a memory object that maps a clock.
<h3>SYNOPSIS</h3>
<pre>
<strong>kern_return_t   clock_map_time</strong>
                <strong>(clock_t</strong>                             <var>clock_name</var>,
                 <strong>memory_object_t</strong>                   <var>clock_memory</var><strong>);</strong>
</pre>
<h3>PARAMETERS</h3>
<dl>
<p>
<dt> <var>clock_name</var> 
<dd>
[in clock-name send right]
The name (or control) port for the clock.
<p>
<dt> <var>clock_memory</var> 
<dd>
[out memory-object-representative send right]
Mapped clock time 
memory object representative.
</dl>
<h3>DESCRIPTION</h3>
<p>
The <strong>clock_map_time</strong> function returns a memory object representative port
representing read access to a memory object that contains (at offset zero) a 
mapped version of the clock time (structure <strong>mapped_tvalspec</strong>).  
The returned right is suitable as an argument for <strong>vm_map</strong>.
<h3>NOTES</h3>
<p>
Not all clocks provide this service, but the REALTIME clock must.
<h3>RETURN VALUES</h3>
<dl>
<p>
<dt> <strong>KERN_FAILURE</strong>
<dd>
The specified clock does not provide this service.
</dl>
<h3>RELATED INFORMATION</h3>
<p>
Functions:
<a href="host_get_clock_service.html"><strong>host_get_clock_service</strong></a>,
<a href="clock_get_attributes.html"><strong>clock_get_attributes</strong></a>,
<a href="clock_get_time.html"><strong>clock_get_time</strong></a>,
<a href="clock_sleep.html"><strong>clock_sleep</strong></a>,
<a href="clock_alarm.html"><strong>clock_alarm</strong></a>.
<p>
Data Structures:
<a href="mapped_tvalspec.html"><strong>mapped_tvalspec</strong></a>.