clear error before doing anything, because we can get

clear error before doing anything, because we can get
trapped by previous error :
php -r '$link = mysqli_init();
var_dump($link->real_connect("127.0.0.1", "unknown", "unknown"));
var_dump($link->real_connect("127.0.0.1", "known", "password"));'

shows the problem. The second connect did not work, as it should be.