#array of simple data types. One word hash keys, etc.
my @inputdata = qw(key1 key2 key3 key4);

my $opt_j = 10; #10 threads

# Worker function
sub do_processing {
   my $indata = shift;
   ## You have to pass a simple value, but here is 
   ## where you get the full data set.
   # my $href = getData($indata);

   # Do your processing

   return "SUCCESS $indata";
}

## Main code
## Begin fork pool

  print "Using $opt_j threads!\n";
  my $io = IO::Socket->new();
  my $select = IO::Select->new();
  my @child;
  my @parent;
  my @pid;
  
  # create children                                                   
+                                                            
  for (my $i = 0; $i < $opt_j; $i++) {
    ($child[$i],$parent[$i]) = $io->socketpair(AF_UNIX,SOCK_STREAM,PF_
+UNSPEC)
      or die "socketpair failed: $!";
    if ($pid[$i] = fork) {
      close $parent[$i];
      $select->add($child[$i]);
      next;
    }
    elsif (defined $pid[$i]) {
      # Child routine
      #print "Child $i started\n";
      my $result;
      my $line;
      close $child[$i];
      print { $parent[$i] } "START\n";
      while ($line = readline $parent[$i]) {
        chomp $line;
        if ($line eq "exit") {
          print { $parent[$i] } "END\n";
          exit;
        }
        if ($line =~ /^DATA (\w+)/) {
          my $data = $1;
          #print "Child $i processing $data\n";
          $result = &do_processing($data);
          print { $parent[$i] } "$result\nRESULT $data\n";
        }
      }
      exit;
      ## End child
    }
    else {
      die "cannot fork: $!";
    }
  }
  # feed childen                                                      
+                                                            
  my $done = 0;
  while (@inputdata || $done < $opt_j) {
    foreach my $socket ($select->can_read()) {
      my $result;
      my $line;
      while ($line = readline $socket) {
        if ($line eq "END\n") {
          $done++;
          last;
        }
        if ($line =~ /^RESULT (\w+)/ || $line eq "START\n") {
          #print "Got $line";
          # Got result, if there are more, then run more.
          print { $socket } (@inputdata ? "DATA " . (shift @inputdata)
+ : "exit") . "\n";
          if ($result) {
           chomp $result;     # need to chop the \n before RESULT
            # process result - should split from function.
            if(defined($1)) {
              #print "$\n";
              print "$1: $result\n";
              $result = "";
            }         
          }
          last;
        }
        $result .= $line;
      }
    }
  }
  # reap children                                                     
+                                                            
  for (my $i = 0; $i < $opt_j; $i++) {
    waitpid($pid[$i], 0);
  }
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