tuple_cb
static int tuple_cb(const char *tuple, int len, void *arg);
TUPLE_DELIMITER_CHARACTER, 1, tuple_cb, garg);
parse_ret = CONF_parse_list(str, TUPLE_DELIMITER_CHARACTER, 1, tuple_cb, &gcb);
typedef int (tuple_cb) (device_t cbdev, device_t child, int id, int len,
tuple_cb *func;