xnu-2422.1.72.tar.gz

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<h2>host_get_clock_control</h2>
<hr>
<p>
<strong>Function</strong> - Return a send right to a kernel clock's control port.
<h3>SYNOPSIS</h3>
<pre>
<strong>kern_return_t   host_get_clock_control</strong>
                <strong>(host_priv_t</strong>                          <var>host_priv</var>,
                 <strong>clock_id_t</strong>                                  <var>id</var>,
                 <strong>clock_ctrl_t</strong>                     <var>clock_control</var><strong>);</strong>
</pre>
<h3>PARAMETERS</h3>
<dl>
<p>
<dt> <var>host_priv</var> 
<dd>
[in host-control send right]
The control port for the host owning the 
clock.
<p>
<dt> <var>id</var> 
<dd>
[in scalar]
The identification of the desired kernel clock.  These values 
are defined in \*L<mach/clock_types.h>\*O.  Although an implementation 
may define additional values, the following values are always defined 
(although only the REALTIME clock is required to be implemented):
<dl>
<p>
<dt> <strong>REALTIME_CLOCK</strong>
<dd>
A moderate resolution clock service that (typically) tracks 
time since the system last boot.
<p>
<dt> <strong>BATTERY_CLOCK</strong>
<dd>
A (typically) low resolution clock (to the second) that
survives power failures or service outages.
<p>
<dt> <strong>HIGHRES_CLOCK</strong>
<dd>
A high resolution clock.
</dl>
<p>
<dt> <var>clock_control</var> 
<dd>
[out clock-control send right]
Control port for the clock.
</dl>
<h3>DESCRIPTION</h3>
<p>
The <strong>host_get_clock_control</strong> function returns a send
right to the control port for 
a kernel clock object.  This right is used to set the clock's
resolution and time.
<h3>RETURN VALUES</h3>
<p>
Only generic errors apply.
<h3>RELATED INFORMATION</h3>
<p>
Functions:
<a href="clock_set_time.html"><strong>clock_set_time</strong></a>,
<a href="clock_set_attributes.html"><strong>clock_set_attributes</strong></a>,
<a href="host_get_clock_service.html"><strong>host_get_clock_service</strong></a>.