i'm start to use ini_get_all function to retrieve all configuration option on a shared host server. in the end i got this chunk of array :

[allow_call_time_pass_reference] => Array
    (
        [global_value] => 1
        [local_value] => 1
        [access] => 6
    )

[allow_url_fopen] => Array
    (
        [global_value] => 1
        [local_value] => 1
        [access] => 4
    )

The PHP manual just give descripstion :

It's possible for a directive to have multiple access levels, which is why access shows the appropriate bitmask values.

so, can anybody explain about 'access' ? ans how to understand its bitmask values ?