1<h2>clock_alarm</h2> 2<hr> 3<p> 4<strong>Function</strong> - Set off an alarm. 5<h3>SYNOPSIS</h3> 6<pre> 7<strong>kern_return_t clock_alarm</strong> 8 <strong>(clock_t</strong> <var>clock_name</var>, 9 <strong>alarm_type_t</strong> <var>alarm_type</var>, 10 <strong>tvalspec_t</strong> <var>alarm_time</var>, 11 <strong>mach_port_t</strong> <var>alarm_reply_port</var><strong>);</strong> 12</pre> 13<h3>PARAMETERS</h3> 14<dl> 15<p> 16<dt> <var>clock_name</var> 17<dd> 18[in clock-name send right] 19The name (or control) port for the clock. 20<p> 21<dt> <var>alarm_type</var> 22<dd> 23[in scalar] 24How to interpret the <var>alarm_time</var> value: 25<dl> 26<p> 27<dt> <strong>TIME_RELATIVE</strong> 28<dd> 29Interpret the alarm time as relative to the current time. 30<p> 31<dt> <strong>TIME_ABSOLUTE</strong> 32<dd> 33Interpret the alarm time as an absolute time. 34</dl> 35<p> 36<dt> <var>alarm_time</var> 37<dd> 38[in structure] 39The time when the alarm is to be sent. 40<p> 41<dt> <var>alarm_reply_port</var> 42<dd> 43[in alarm receive (to be converted to send-once) right] 44A port into 45which the alarm message is to be sent. 46</dl> 47<h3>DESCRIPTION</h3> 48<p> 49The <strong>clock_alarm</strong> function requests that a clock send 50an alarm message to a 51specified port at a given future time. The alarm message is specified by the 52<strong>clock_alarm_reply</strong> server interface. 53<h3>NOTES</h3> 54<p> 55If the specified alarm time is in the past, the alarm message 56is sent immediately 57and time-stamped with the current time. Otherwise, the alarm is queued and 58delivered at the specified alarm time and time-stamped at that time. 59<p> 60The alarm will be serviced at the service time nearest the specified 61alarm time 62as governed by the current clock alarm resolution. 63<p> 64Not all clocks implement this service, but the REALTIME clock must. If the 65clock does not provide this service, this call is ignored. 66<h3>RETURN VALUES</h3> 67<p> 68Only generic errors apply. 69<h3>RELATED INFORMATION</h3> 70<p> 71Functions: 72<a href="host_get_clock_service.html"><strong>host_get_clock_service</strong></a>, 73<a href="clock_get_attributes.html"><strong>clock_get_attributes</strong></a>, 74<a href="clock_get_time.html"><strong>clock_get_time</strong></a>, 75<a href="clock_sleep.html"><strong>clock_sleep</strong></a>, 76<a href="clock_alarm_reply.html"><strong>clock_alarm_reply</strong></a>. 77<p> 78Data Structures: 79<a href="tvalspec.html"><strong>tvalspec</strong></a>. 80