variable.c:850
static int
generic_ivar_remove(obj, id, valp)
    VALUE obj;
    ID id;
    VALUE *valp;
{
    st_table *tbl;
    int status;

    if (!generic_iv_tbl) return 0;
    if (!st_lookup(generic_iv_tbl, obj, (st_data_t *)&tbl)) return 0;
    status = st_delete(tbl, &id, valp);
    if (tbl->num_entries == 0) {
	st_delete(generic_iv_tbl, &obj, (st_data_t *)&tbl);
	st_free_table(tbl);
    }
    return status;
}
