package Iter::Output;

sub new {
   my ( $class, $path ) = @_;
   my ( $order_id, $fh, %hold ) = ( 1 );

   # Note: Do not open the file handle here, during construction.
   # The reason is that sharing will fail (cannot serialize $fh).

   MCE::Shared->share(
      bless [ $path, $fh, \$order_id, \%hold ], $class
   );
}

sub send {
   ...
}

sub close {
   ...
}


##</code><code>##

package Iter::Input;

sub new {
   my ( $class, $chunk_size, $iterations ) = @_;
   my ( $chunk_id, $seq_a ) = ( 0, 1 );

   MCE::Shared->share(
      bless [ $iterations, $chunk_size, \$chunk_id, \$seq_a ], $class
   );
}

sub recv {
   ...
}


##</code><code>##

use threads;

...

test_threads();

sub test_threads {
   my $start = time;
   my @thrs;

   # must save threads to join later
   push @thrs, threads->create('work') for (1..$num_workers);

   # wait for threads to finish
   $_->join for @thrs;

   # close the shared file handle, flushes buffer
   $iter_o->close();

   printf STDERR "testa done in %0.02f seconds\n", time - $start;
}