oracular (3) IO::Async::Timer::Periodic.3pm.gz

NAME

       "IO::Async::Timer::Periodic" - event callback at regular intervals

SYNOPSIS

          use IO::Async::Timer::Periodic;

          use IO::Async::Loop;
          my $loop = IO::Async::Loop->new;

          my $timer = IO::Async::Timer::Periodic->new(
             interval => 60,

             on_tick => sub {
                print "You've had a minute\n";
             },
          );

          $timer->start;

          $loop->add( $timer );

          $loop->run;

DESCRIPTION

       This subclass of IO::Async::Timer implements repeating events at regular clock intervals. The timing may
       or may not be subject to how long it takes the callback to execute. Iterations may be rescheduled runs at
       fixed regular intervals beginning at the time the timer was started, or by a fixed delay after the
       previous code has finished executing.

       For a "Timer" object that only runs a callback once, after a given delay, see instead
       IO::Async::Timer::Countdown. A Countdown timer can also be used to create repeating events that fire at a
       fixed delay after the previous event has finished processing. See als the examples in
       "IO::Async::Timer::Countdown".

EVENTS

       The following events are invoked, either using subclass methods or CODE references in parameters:

   on_tick
       Invoked on each interval of the timer.

PARAMETERS

       The following named parameters may be passed to "new" or "configure":

   on_tick => CODE
       CODE reference for the "on_tick" event.

   interval => NUM
       The interval in seconds between invocations of the callback or method. Cannot be changed if the timer is
       running.

   first_interval => NUM
       Optional. If defined, the interval in seconds after calling the "start" method before the first
       invocation of the callback or method. Thereafter, the regular "interval" will be used. If not supplied,
       the first interval will be the same as the others.

       Even if this value is zero, the first invocation will be made asynchronously, by the containing "Loop"
       object, and not synchronously by the "start" method itself.

   reschedule => STRING
       Optional. Must be one of "hard", "skip" or "drift". Defines the algorithm used to reschedule the next
       invocation.

       "hard" schedules each iteration at the fixed interval from the previous iteration's schedule time,
       ensuring a regular repeating event.

       "skip" schedules similarly to "hard", but skips over times that have already passed. This matters if the
       duration is particularly short and there's a possibility that times may be missed, or if the entire
       process is stopped and resumed by "SIGSTOP" or similar.

       "drift" schedules each iteration at the fixed interval from the time that the previous iteration's event
       handler returns. This allows it to slowly drift over time and become desynchronised with other events of
       the same interval or multiples/fractions of it.

       Once constructed, the timer object will need to be added to the "Loop" before it will work. It will also
       need to be started by the "start" method.

AUTHOR

       Paul Evans <leonerd@leonerd.org.uk>