Function - Set off an alarm.
kern_return_t clock_alarm (clock_t clock_name, alarm_type_t alarm_type, tvalspec_t alarm_time, mach_port_t alarm_reply_port);
The clock_alarm function requests that a clock send an alarm message to a specified port at a given future time. The alarm message is specified by the clock_alarm_reply server interface.
If the specified alarm time is in the past, the alarm message is sent immediately and time-stamped with the current time. Otherwise, the alarm is queued and delivered at the specified alarm time and time-stamped at that time.
The alarm will be serviced at the service time nearest the specified alarm time as governed by the current clock alarm resolution.
Not all clocks implement this service, but the REALTIME clock must. If the clock does not provide this service, this call is ignored.
Only generic errors apply.
Functions: host_get_clock_service, clock_get_attributes, clock_get_time, clock_sleep, clock_alarm_reply.
Data Structures: tvalspec.