main.pl <- B.pm <- A.pm

##</code><code>##

# normal run, will finish after 7 iterations
# 'ipcs -a' shows everything was cleaned up properly

perl main.pl 2 2

# another normal run, but this time hit CTRL-C before the last iter
# `ipcs -a` shows SIGINT handler properly cleans up

perl main.pl 2 2 # hit CTRL-C

# send in 1 as the first param to have B.pm die() after 5 iters
# 'ipcs -a' shows everything cleaned up properly

perl main.pl 1 1

# PROBLEMATIC RUN
# send in three args which will die() main.pl
# 'ipcs -a' shows a leak of a memory segment

perl main.pl 2 2 2

##</code><code>##

use strict;
use warnings;

package A;

use base 'Exporter';
our @EXPORT = qw(%hash);

use IPC::Shareable;

$SIG{INT}     = sub { 
    print "package A has caught the INT signal\n";
    IPC::Shareable->clean_up_all; 
    exit; 
};
$SIG{__DIE__} = sub { 
    print "package A has caught the die() signal\n";
    IPC::Shareable->clean_up_all; 
    exit; 
};

our %hash;
my $tied;

BEGIN {
    $tied = tie %hash, 'IPC::Shareable', {
        key => 'test',
        create => 1
    };
}

END {
    IPC::Shareable->clean_up_all;
}

sub run {
    print "A: ";
    print "a: $hash{a}, a: $hash{b}\n";
}

1;

##</code><code>##

use warnings;
use strict;

package B;

use lib '.';
use A;

our %hash;
my $count = 0;

sub run {
    my ($self, $x, $y) = @_;
    $hash{a} = $x;
    $hash{b} = $y;

    while (1){
        print "B: ";
        print "a: $hash{a}, b: $hash{b}\n";
        A->run;
        die "whoops!" if $count == 4 && $x == 1;
        last if $count == 6;
        $count++;
        sleep 1;
    }
}
1;

##</code><code>##

use warnings;
use strict;

use lib '.';

use B;

print "\nneed 2 (or 3 if die()) args...\n" and exit if @ARGV < 2;

print "procID: $$\n";

if (defined $ARGV[2]){
    die "main script has died";
}

B->run(@ARGV);