underscore($str)

create_captcha([$data = ''[, $img_path = ''[, $img_url = ''[, $font_path = '']]]])

memory_usage()

redirect($uri = '', $method = 'auto', $code = NULL)

do_upload([$field = 'userfile'])

unmark_temp($key)

report([$result = array()])

The following pages describe the broad concepts behind CodeIgniter:

initialize([array $config = array()[, $reset = TRUE]])

update([$items = array()])