syswrite handler, message

##</code><code>##

# Parallelise the writing into the pipes
my $pm = Parallel::ForkManager->new($lp);

foreach (@str_handles) {
  my $pid = $pm->start and next;

  syswrite $_->{handle},
           join(" ",
                  $_->{chunksize},
                  $_->{A_cols},
                  @A_lines[$_->{start}.. $_->{end}],
                  @B_lines,
                  "\cN"
               );
  $pm->finish;
}