my $t= XML::Twig->new(load_DTD => 1,DTDHandler=>\&checkit )->parsefile( "$xmlfile");

 sub checkit
 {
 	my ($twig, $dtd) = @_;
 	my $root=$twig->root;
 	my @text=$root->att_names;
 	if (grep /schemaLocation/, @text) 
 	{
            print "found schema\n";
	}
	else
	{
 		if ($twig->{twig_doctype})
 		{ 	
  			print "found dtd\n";
 		}
 		else
 		{ 
                       print "no dtd/schema defined\n"
 		}

	}
}