package IPC_Class
use strict;
use warnings;

sub new
{
  shift; my $self = { 'cmds' => undef, @_ };
  defined $self->{'cmds'} or die "ERROR: didn't get CMD in constructor.";
  IPC::Shareable->clean_up_all;
  bless $self; return $self;
}

sub start {
  my $self = shift;
  my $fh_glob_ref = shift;
  ...
  # the cmd "grep 'zzz'" in the next line will fail.
  my $h = IPC::Run::start(['sort'], '<pipe', $fh_glob_ref, '|', ['grep', 'zzz'], '>', $writefh, "2>", $writefh) or die "Error: $!\n";
  $self->{'h'} = h;
}

sub finish {
  my $self = shift;
  $h = $self->{'h'};
  if (!$h->finish()) {
    for ($h->full_results) { print "$_\n" };
  }
}