f_arg
(*fn->f_callback)(fn->f_arg,
(*fn->f_callback)(fn->f_arg,
fn->f_arg = arg;
u->u_func[f].f_arg = NULL;
fn->f_arg = NULL;
void *f_arg;
static const struct f_arg fflagopts[] = {
const struct f_arg *arg;
const struct f_arg *arg;