php error reporting level per IP

Question

I understand that it is possible to alter the PHP error reporting level site-wide, but can I report a different error level to a particular client (IP address)?

Answer 1

Yes:

if ($_SERVER["HTTP_HOST"] == "my.ip.address")
 error_reporting(my_custom_reporting_level);

if you want to display verbose error messages to an administrator, you might be better off with an authentication system though.

Answer 2

It is possible natively as of PHP 5.3: http://php.net/ini.sections

Before that, you can manage it in the Vhost apache configuration.
SetEnv php_directive value