You need a $sadmysqli->real_connect(); after creating the object. Mind the note 
on the page: "Calling the constructor with no parameters is the same as calling 
mysqli_init()." Add the real_connect() call and you can ini_set the mysqli ini 
settings as much as your little heart desires and it'll work as expected: 

[david@oslo:~]$ mysql -u root -p
Enter password: 

mysql> use php;
Database changed
mysql> select * from test;
+--------+-------+------------+
| idtest | fname | lname      |
+--------+-------+------------+
|      0 | david | tajchreber |
+--------+-------+------------+
1 row in set (0.00 sec)

mysql> exit
Bye
[david@oslo:~]$ cat t.php 
<?php 

error_reporting(E_ALL | E_STRICT);

ini_set('mysqli.default_host', 'localhost');
ini_set('mysqli.default_socket', '/var/run/mysqld/mysqld.sock');
ini_set('mysqli.default_user', 'root');
ini_set('mysqli.default_pw', 'root');

$m = new MySQLi();
var_dump($m->real_connect());
var_dump($m->ping());
var_dump($m->select_db('php'));
var_dump($m->query('select * from test;', MYSQLI_USE_RESULT)->fetch_all());

[david@oslo:~]$ php t.php 
bool(true)
bool(true)
bool(true)
array(1) {
  [0]=>
  array(3) {
    [0]=>
    string(1) "0"
    [1]=>
    string(5) "david"
    [2]=>
    string(10) "tajchreber"
  }
}

the problem is that the documentation is ambiguous (or disingenuous) in the method 
signature, not that it's possible to use mysql_real_connect to remedy this.

It's a notation issue: the signature implies that missing arguments are substituted with 
the defaults, but if this is not the case, then you can at least fix this by implying that 
either the host argument is required or the constructor will only initialize a connection 
rather than opening one.


The problem is basically this: 

    float pow($x [, $exp=1])

but then saying 

    if $exp is not specified, the return value may not be a float.

of course this is a ridiculous example, but it's also easily fixed by changing either the 
signature to read:

    mixed pow($x [, $exp=1])
or
    float pow($x, $exp)

but the original example is disingenuous because either the type is incorrect or the second 
argument is not really optional. 


In this *exact way* it's disingenuous to imply that the default values are optional when in 
reality they are required to open a connection.

This could be fixed in the documentation by changing the line

    "Opens a connection to the MySQL Server running on."

to read 

    "Opens a connection to a MySQL Server or initializes a MYSQL object suitable for 
mysqli_options() and mysqli_real_connect() if no arguments are passed to the constructor"

because this effectively sums up the behavior of the constructor. Otherwise, the 
implication is that calling this function in *any* way will open a connection (rather than 
*potentially* opening one or even just *initializing* one.)