From your code it looks like:

• Pooled_function is being executed in the child process
• the value of $pclass read from $parentfh indicates what work the child process should perform in addition to what file the output should be saved in

Are these correct assumptions?

If so, you can use the tee command, but it requires juggling some file handles:

sub Pooled_function {

  open(my $STDOUT_SAVE, ">&STDOUT"); # save current STDOUT

  while (<$parentfh>) {
    chomp;
    my ($pclass, $copy_to_console) = split(' ', $_, 2);
    my $file = ...;
    if ($copy_to_console) {
      open(STDOUT, ">&", $STDOUT_SAVE);
      open(OUT, "|-", "tee", $file);
    } else {
      open(OUT, ">", $file);
    }
    open(STDOUT, ">&OUT");
    open(STDERR, ">&OUT");

    # Do the stuff

    close(STDOUT);
    close(STDERR);
    close(OUT);
  }
  close($parentfh);
}
[download]

Alternatively, in the Perl Cookbook, there is an example of how to implement tee within perl by using tied file handles. Look for the Tie::Tee example at the end of Chapter 13.