How to make mysqli connect function?

As some users have suggested (and is the best way), return the mysqli instance

function getConnected($host,$user,$pass,$db) {

   $mysqli = new mysqli($host, $user, $pass, $db);

   if($mysqli->connect_error) 
     die('Connect Error (' . mysqli_connect_errno() . ') '. mysqli_connect_error());

   return $mysqli;
}

Example:

$mysqli = getConnected('localhost','user','password','database');