#!/usr/bin/perl
use FileHandle;
use threads;

$|++;

$thr = threads->new(\&sub1);

sub sub1 {
  while(1){
  print "THREAD: in da zone !! :) \n\n";
  sleep 1;
  };
}

my $fh_in = FileHandle->new();
$fh_in = *STDIN{IO};                                                                   

while (<$fh_in>) {                                                                        
    my $stuff = $_;
    if (defined($stuff) and $stuff ne ''){
      print "MAIN:", $stuff , "\n" ;
    }
 }