Bind Error

Hy, first of all ty for your submission.

the code that I'm using for binding is this:
if (isset($arg_array[0])) {
array_unshift($arg_array, $types);

for ($i = 1; $i < count($arg_array); $i++)
$arg_array[$i] = &$arg_array[$i];

$bind = @call_user_func_array(array
($this->stmt,
'bind_param'), $arg_array);
}

During the execution if there's a bind error the message display only a void string

if I try to use var_dump($this->db->error) the ourput is string(0)""

any suggestion?