osfmk/man/host_get_clock_control.html

   1 <h2>host_get_clock_control</h2>
   2 <hr>
   3 <p>
   4 <strong>Function</strong> - Return a send right to a kernel clock's control port.
   5 <h3>SYNOPSIS</h3>
   6 <pre>
   7 <strong>kern_return_t   host_get_clock_control</strong>
   8                 <strong>(host_priv_t</strong>                          <var>host_priv</var>,
   9                  <strong>clock_id_t</strong>                                  <var>id</var>,
  10                  <strong>clock_ctrl_t</strong>                     <var>clock_control</var><strong>);</strong>
  11 </pre>
  12 <h3>PARAMETERS</h3>
  13 <dl>
  14 <p>
  15 <dt> <var>host_priv</var>
  16 <dd>
  17 [in host-control send right]
  18 The control port for the host owning the
  19 clock.
  20 <p>
  21 <dt> <var>id</var>
  22 <dd>
  23 [in scalar]
  24 The identification of the desired kernel clock.  These values
  25 are defined in \*L<mach/clock_types.h>\*O.  Although an implementation
  26 may define additional values, the following values are always defined
  27 (although only the REALTIME clock is required to be implemented):
  28 <dl>
  29 <p>
  30 <dt> <strong>REALTIME_CLOCK</strong>
  31 <dd>
  32 A moderate resolution clock service that (typically) tracks
  33 time since the system last boot.
  34 <p>
  35 <dt> <strong>BATTERY_CLOCK</strong>
  36 <dd>
  37 A (typically) low resolution clock (to the second) that
  38 survives power failures or service outages.
  39 <p>
  40 <dt> <strong>HIGHRES_CLOCK</strong>
  41 <dd>
  42 A high resolution clock.
  43 </dl>
  44 <p>
  45 <dt> <var>clock_control</var>
  46 <dd>
  47 [out clock-control send right]
  48 Control port for the clock.
  49 </dl>
  50 <h3>DESCRIPTION</h3>
  51 <p>
  52 The <strong>host_get_clock_control</strong> function returns a send
  53 right to the control port for
  54 a kernel clock object.  This right is used to set the clock's
  55 resolution and time.
  56 <h3>RETURN VALUES</h3>
  57 <p>
  58 Only generic errors apply.
  59 <h3>RELATED INFORMATION</h3>
  60 <p>
  61 Functions:
  62 <a href="clock_set_time.html"><strong>clock_set_time</strong></a>,
  63 <a href="clock_set_attributes.html"><strong>clock_set_attributes</strong></a>,
  64 <a href="host_get_clock_service.html"><strong>host_get_clock_service</strong></a>.