use Win32::Semaphore;
my $sem = new Win32::Semaphore(0,1)
...
   if( my $code_pid = fork() ) {

       sleep(5);
       $sem->release();
   }
   elsif( defined $code_pid ) {

       print "Process executing..";
       _spin();
       bless $sem, 'do not destroy';
       exit 0;
   ...
sub _spin {

   SPIN: while(! $sem->wait(0)) {
...