class CI_Form_validation set_rules($field[, $label = ''[, $rules = '']])

db_connect($persistent = TRUE)

get_request_header($index[, $xss_clean = FALSE])

list_tables([$constrain_by_prefix = FALSE])

set_data($data)

days_in_month([$month = 0[, $year = '']])

custom_row_object($n, $type)

directory_map($source_dir[, $directory_depth = 0[, $hidden = FALSE]])

xml_convert($str[, $protect_all = FALSE])

is_ajax_request()