use strict; use warnings; use feature 'say';
use Time::HiRes qw/ time usleep /;
use MCE::Shared;

say sprintf '%-5s %-17s %-s', 'PID', 'Time', 'Action';

my $shared = MCE::Shared->condvar(0);
say sprintf '%s %.06f Init val: %s', $$, time, $shared->get;

my $pid = fork;

if ( $pid ) {
    for ( 0 .. 19 ) {
        say sprintf '%s %.06f write: %s', $$, time, $shared->incr;
        usleep 10000;
    }
} else {
    while (1) {
        usleep 50000;
        say sprintf '%s %.06f READ: %s', $$, time, $shared->get;
    }
}

__END__