PHP does not throw exception if mysqli is not enabled -

i have

<?php error_reporting(e_all); ini_set('display_errors', 1); require_once "configuration.php"; header('content-type: application/json'); try {        $mysqli = new mysqli(mysql_server, mysql_username, mysql_password, mysql_database);     $mysqli->set_charset("utf8"); } catch (exception $e) {     echo json_encode(         array(             'msg' => $e->getmessage()         )     ); } 

and if mysqli not enabled not catch error:

fatal error: uncaught error: class 'mysqli' not found in c:\test\db_connect.php:8
stack trace:
#0 c:\test\getcontacts.php(2): require_once()
#1 {main} thrown in c:\test\db_connect.php on line 8

what can catches error?

i have tried 1 didn't work:

<?php error_reporting(e_all); ini_set('display_errors', 1); require_once "configuration.php"; header('content-type: application/json'); try {     if(!extension_loaded('mysqli'))     {         throw new exception('mysqli not enabled');     }      $mysqli = new mysqli(mysql_server, mysql_username, mysql_password, mysql_database);     $mysqli->set_charset("utf8"); } catch (exception $e) {     echo json_encode(         array(             'msg' => $e->getmessage()         )     ); } 

this 1 not halt, continues execute script.

{"msg":"mysqli not enabled"}
notice: undefined variable: mysqli in c:\test\getcontacts.php on line 99

fatal error: uncaught error: call member function query() on null in c:\test\getcontacts.php:99 stack trace: #0 {main} thrown in c:\test\getcontacts.php on line 99

it's odd wouldn't installed if you're rolling own guess omitted. check see if procedural functions exist

if(!function_exists('mysqli_connect')) {     throw new exception('mysqli not enabled'); }