use strict;
use warnings;

use POE qw(Wheel::Run);

POE::Session->create
  ( inline_states =>
      { _start => \&start,
        stdout => \&stdout,
        done => \&done,
  

      },
        heap => { sum => 0 } # here your sum will endup
  );

POE::Kernel->run();
exit;

sub start{
    my ( $kernel, $heap ) = @_[KERNEL, HEAP];

    # If you have more functions with similar interface, just create a loop
    my $function = POE::Wheel::Run->new(
        Program => sub { Function_1( 10 ) },
        StdoutEvent => 'stdout',
        CloseEvent => 'done',
    );
    $heap->{function}->{ $function->ID } = $function;
    
    $function = POE::Wheel::Run->new(
        Program => sub { Function_2( 10 ) },
        StdoutEvent => 'stdout',
        CloseEvent => 'done',
    );

    # store the wheel, so that its refcount is incremented
    $heap->{function}->{ $function->ID } = $function;

}

sub stdout {
    my ($heap, $result ) = @_[HEAP, ARG0];
    $heap->{sum}+=$result;
}

sub done{
    my ( $kernel, $heap, $function_id ) = @_[ KERNEL, HEAP, ARG0 ];
    # delete the reference to the function that has ended, so it may be garbage
    # collected
    delete $heap->{function}->{$function_id};
    # No more childs, print the total amount
    # alternately you could send a message back to a parent session with the
    # result
    if ( scalar( keys( %{$heap->{function}})) == 0 ){
        print "RESULT: ", $heap->{sum},"\n";
    }
}


# The STDOUT of your function is "caught" and returned
sub Function_1 {
    my $up_bound1 = shift;
   
    my $total_f1;
    foreach  my $in (0..$up_bound1) {
        $total_f1 += $in/3;
    }
    
    print "$total_f1\n";
    return $total_f1;
}

sub Function_2 {
    my $up_bound2 = shift;
    
    my $total_f2;
    foreach  my $in (0 .. $up_bound2) {
           $total_f2 += $in;
    }
    print "$total_f2\n";
    return $total_f2;
}