$thr = threads->new(\&sub1, "THREAD1 :");
    ...
    @ReturnData = $thr->join; 
    ...

##</code><code>##

    ($thr) = threads->new(\&sub1, "THREAD1 :");
    ...
    @ReturnData = $thr->join; 
    ...

##</code><code>##

          {
            lock $foo;
            $foo=0;
          }

##</code><code>##

    print " Final value :$foo\n";