Schedule::ByClock - Give back the control to the caller at given times.
use Schedule::ByClock;
# Constructor $th = Schedule::ByClock->new([second [,second [,...]]);
# Methods @seconds = $th->set_control_list([second [,second [,...]]); @seconds = $th->get_control_list();
$second = $th->get_control_on_second([second [,second [,...]]);
$version = $th->get_version();
Schedule::ByClock makes use of the Time::localtime package.
This module implements an 'intelligent' (?) layer over
sleep(). Call the module when you want to sleep to a given
second in the minute without having to calculate how long to wait.
Use with multiple 'second' values to sleep until the chronologically first 'second' in the list.
Note that all times used in Schedule::ByClock are calculated from the local time in the computer where Schedule::ByClock is executed.
Assume that you want to do something repeatedly every minute, when the seconds show for instance 34.
Assume that you want to do something (maybe just once) the next time the
seconds in the computer shows 23. Assume that 'now' is 18. You would need
to use sleep and to calculate how many seconds there are from 'now' till
23. Easy, 23 - 18 = 5. sleep(5); Then, assume that 'now' is
28. I.e. 23 - 28 = 55. (Huh?)
Assume that you want to do something repeatedly, when the seconds show either 12 or 45 or 55, whichever comes first compared to 'now'. Assume that 'now' is 56. You would have to find out if it's 12, 45 or 55 that comes 'after' 56. Then you would have to calculate 12 - 56 = 16. (Right?)
You should have got the picture by now. (Or I have failed. :-)
All examples below use this constructor.
$th = Schedule::ByClock->new(12,8,55); # Constructor with
three 'seconds' values.
At 09:09:24, you call:
$rc = $th->get_control_on_second(); # This will return at
09:09:55.
$rc = $th->set_control_list(23);
At 09:09:24, you call:
$rc = $th->get_control_on_second(); # This will return at
09:10:23.
$rc = $th->set_control_list(); # Note! Empty list.
At 09:09:24, you call:
$rc = $th->get_control_on_second(); # This will return
immediately (with return value undef).
At 09:09:25, you call:
$rc = $th->get_control_on_second(12); # This will return at
09:10:12.
At 09:09:55, you call:
$rc = $th->get_control_on_second(); # This will return at
09:10:55, one minute later.
Constructs a new ByClock object with an optional list of 'seconds' for pre-programmed returns.
Any 'second' that is not within the range 0 - 59 will be ignored and a warning (carp) will be written to the terminal.
Store a list of 'seconds' in the ByClock object to be used in future calls
to get_control_on_second(), overriding the old list (if any).
Any 'second' that is not within the range 0 - 59 will be ignored and a
warning (carp) will be written to the terminal. If no 'seconds' are given
(no parameters), then the internally stored list of 'seconds' will be
cleared. Returns the newly stored list of 'seconds'.
Returns a list of 'seconds' currently stored in the ByClock object.
Sleep and return control to the caller at the chronologically first second in the pre-programmed list of 'seconds'. Returns the second that corresponds to the return. If the internal list of seconds is empty the call will immediately return undef.
Sleep and return control to the caller at the chronologically first second in the provided list of 'seconds'. This call will ignore the internally stored list of seconds (if any). Returns the second that corresponds to the return.
Returns the current version of Schedule::ByClock.
Gustav Schaffter <gschaffter@cyberjunkie.com>
Copyright (c) 1999 Gustav Schaffter. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.