object &PEAR_Config::singleton (
string $user_file = ''
, string $system_file = ''
If you want to keep only one instance of this class in use, this method will give you a reference to the last created PEAR_Config object if one exists, or create a new object.
file to read user-defined options from
file to read system-wide defaults from
an existing or new PEAR_Config instance
This function should be called statically.