According to SQLite documentation, All tables have rowid by default, and it cannot be removed. And this rowid can be accessed with rowid, oid or _rowid_.
Anyway database users can add the new column with the names freely, and the columns will be hidden. The only way to access rowid is making a new column with INTEGER PRIMARY KEY.
This is my current understanding. And with this, I have no reliable way to get the rowid if user hide all the columns and user didn't make any PK column. I have thought about adding temporary PK column, but this is unreliable too. If this is true, this doesn't make sense. Because the data is always available, and I just cannot access because there's no appropriate interface.
So I think there should be a way to access this data reliably. But I couldn't find anything with C API. Can I have some guidance for this?