gc.c:1433
static VALUE
os_each_obj(argc, argv)
    int argc;
    VALUE *argv;
{
    VALUE of;

    rb_secure(4);
    if (rb_scan_args(argc, argv, "01", &of) == 0) {
	return os_live_obj();
    }
    else {
	return os_obj_of(of);
    }
}
