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

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