The library(time) provides timing and alarm functions.
Alarms are thread-specific, i.e., creating an alarm causes the alarm
goal to be called in the thread that created it. The predicate current_alarm/4
only reports alarms that are related to the calling thread. If a thread
terminates, all remaining alarms are silently removed. Most applications
use call_with_time_limit/2.
- [det]alarm(+Time,
:Callable, -Id)
- [det]alarm(+Time,
:Callable, -Id, +Options)
- Set up an alarm to be signaled Time seconds from now. If the
alarm expires, Callable is called asynchronously. Callable
can be used to raise an exception using throw/1
to abort some execution.
Options is a list of Name(Value) options. Currently
defined options are:
- remove(Bool)
- If
true (default false), remove the
alarm-event (as
remove_alarm/1) after it has
been fired.
- install(Bool)
- If
false (default true) do not install the
alarm. It must be installed separately using install_alarm/1.
- [det]alarm_at(+Time,
:Callable, -Id)
- [det]alarm_at(+Time,
:Callable, -Id, +Options)
- As alarm/3 and alarm/4,
but schedule the alarm at an absolute point in time.
- See also
- date_time_stamp/2.
- [det]install_alarm(+Id)
- [det]install_alarm(+Id,
+RelTime)
- Install an alarm allocated using alarm/4
with the
install(false) option or de-activated using uninstall_alarm/1.
With a given
RelTime, the alarm is scheduled at the RelTime
from now. Otherwise it is scheduled on the same (absolute) time on which
is was created.
- [det]uninstall_alarm(+Id)
- De-activate an alarm. This does not invalidate Id, but
ensures that the alarm will not fire. The alarm can be rescheduled to
the original time using install_alarm/1
or to a new time using
install_alarm/2.
- [det]remove_alarm(+Id)
- Remove an alarm. If it has not yet been fired, it never will.
- [nondet]current_alarm(?Time,
:Goal, ?Id, ?Status)
- Enumerate the alarms in the schedule. Time is the absolute
time the event is scheduled for (see also get_time/1). Goal
is the goal to execute, Id is the identifier and Status
is the scheduling status. It takes the value
done if the
alarm has been fired, next if the event is the next to be
executed and
scheduled otherwise.
- [det]call_with_time_limit(+Time,
:Goal)
- [det]call_with_time_limit(+Time,
:Goal, +Context)
- Call Goal, while watching out for a (wall-time) limit. If
this limit is exceeded, the exception
time_limit_exceeded
is raised.
call_with_time_limit/3
throws time_limit_exceeded(Context). Goal is
called as in once/1.
- throws
time_limit_exceeded (call_with_time_limit/2)
or
time_limit_exceeded(Context) (call_with_time_limit/3).