set_header($header[, $replace = TRUE])

flush_cache()

set_content_type($mime_type[, $charset = NULL])

charsets()

create_table($table[, $if_not_exists = FALSE[, array $attributes = array()]])

rename_table($table_name, $new_table_name)

is_https()

segment_array()

custom_result_object($class_name)

escape_like_str($str)