variable.c:1255
VALUE
rb_autoload_p(mod, id)
    VALUE mod;
    ID id;
{
    struct st_table *tbl = RCLASS(mod)->iv_tbl;
    VALUE val;

    if (!tbl || !st_lookup(tbl, id, &val) || val != Qundef) {
	return Qnil;
    }
    return autoload_file(mod, id);
}
