Reserved Names
In order to help out, CodeIgniter uses a series of function, method, class and variable names in its operation. Because of this, some names cannot be used by a developer. Following is a list of reserved names that cannot be used.
Controller names
Since your controller classes will extend the main application controller you must be careful not to name your methods identically to the ones used by that class, otherwise your local methods will override them. The following is a list of reserved names. Do not name your controller any of these:
CI_Controller
Default
index
Functions
load_class()
is_loaded()
get_config()
_error_handler()
_exception_handler()
_stringify_attributes()
Variables
$config
$db
$lang
Constants
ENVIRONMENT
FCPATH
SELF
BASEPATH
APPPATH
VIEWPATH
CI_VERSION
MB_ENABLED
ICONV_ENABLED
UTF8_ENABLED
FILE_READ_MODE
FILE_WRITE_MODE
DIR_READ_MODE
DIR_WRITE_MODE
FOPEN_READ
FOPEN_READ_WRITE
FOPEN_WRITE_CREATE_DESTRUCTIVE
FOPEN_READ_WRITE_CREATE_DESTRUCTIVE
FOPEN_WRITE_CREATE
FOPEN_READ_WRITE_CREATE
FOPEN_WRITE_CREATE_STRICT
FOPEN_READ_WRITE_CREATE_STRICT
SHOW_DEBUG_BACKTRACE
EXIT_SUCCESS
EXIT_ERROR
EXIT_CONFIG
EXIT_UNKNOWN_FILE
EXIT_UNKNOWN_CLASS
EXIT_UNKNOWN_METHOD
EXIT_USER_INPUT
EXIT_DATABASE
EXIT__AUTO_MIN
EXIT__AUTO_MAX