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>