Re: How do I pause real time in Perl

This code does what you want (at least, as far as I can tell from your very hard-to-read posting):

#!/usr/bin/env perl

use strict;
use warnings;

use Time::HiRes qw{usleep};
use Time::Piece;

my ($countdown, $check) = @ARGV;
$countdown = 60 unless defined $countdown;
$check ||= 10;  # Avoid "Illegal modulus zero" error
my $countdown_remaining = Time::Piece->strptime(0 => '%S');
$countdown_remaining += $countdown;
my $continue_re = qr{(?:^$|^[Yy])};

print_timestamp('Started');

{
    local $| = 1;

    do {
        print_countdown($countdown_remaining);
        my $seconds_remaining = $countdown_remaining->epoch;
        print "\n" and last unless $seconds_remaining;

        if (($countdown - $seconds_remaining) % $check == 0
             &&
             $countdown > $seconds_remaining
        ) {
            print_timestamp("\nPaused ");
            print "Continue? ([Y]/n): ";
            chomp(my $reply = <STDIN>);
            last unless $reply =~ $continue_re;
            print_timestamp('Resumed');
        }

        usleep 1_000_000;
    } while $countdown_remaining--;
}

print_timestamp("Finished");

sub print_countdown {
    printf "\r%s" => shift->strftime('%H:%M:%S');
}

sub print_timestamp {
    print shift, ' at: ', scalar(localtime), "\n";
}
[download]

By default, it runs with a 60 second timer and 10 second check:

$ pm_time_countdown.pl
Started at: Sat Nov  2 18:02:36 2013
00:00:50
Paused  at: Sat Nov  2 18:02:46 2013
Continue ([Y]/n): 
Resumed at: Sat Nov  2 18:02:50 2013
...
Paused  at: Sat Nov  2 18:03:35 2013
Continue ([Y]/n): 
Resumed at: Sat Nov  2 18:03:40 2013
00:00:00
Finished at: Sat Nov  2 18:03:50 2013
[download]

You can pass any values on the command line:

$ pm_time_countdown.pl 3 2
Started at: Sat Nov  2 18:30:23 2013
00:00:01
Paused  at: Sat Nov  2 18:30:25 2013
Continue? ([Y]/n): 
Resumed at: Sat Nov  2 18:30:26 2013
00:00:00
Finished at: Sat Nov  2 18:30:27 2013
[download]

Currently, the countdown needs to be less than a day (you could extend that):

$ pm_time_countdown.pl 86337 600
Started at: Sat Nov  2 17:44:22 2013
23:48:57
Paused  at: Sat Nov  2 17:54:23 2013
Continue ([Y]/n): n
Finished at: Sat Nov  2 18:02:00 2013
[download]

The two modules I've used are both builtins: you have them already; there's nothing to install from CPAN.

Time::HiRes provides high resolution time functions: usleep() is the only one I've used here. The builtin sleep() function is not very accurate: the doco suggests the best you could guarantee might be: 0s < sleep(1) < 2s.

I've used Time::Piece to handle the countdown value and generate the 'HH:MM:SS' formats. As you can see, this was a much easier way to code it than your multiple '($end_time - $time) ...' technique.

The rest of the code is pretty straightforward and shouldn't hold any surprises. It should run under Perl v5.8 or later versions.

-- Ken

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