example.pl

sub copyText {
   my ($arg1, $arg2) = @_;
   while ($arg1) {
      $arg2->Empty();
      $arg1 = $arg2->IsText();
      sleep(1);
   }

   $_[0] = $arg1;   # arg1 is passed by reference
}

my $target = "Bad Info";
my $source = "Hello World";
copyText( $target, $source );

if( $target == $source ){ 
   say "Success";
}