unqlite not writing to disk after calling store value function

Using unqlite I call unqlite_kv_store to write my key and value. Then the program terminates. I didn't call unqlite_close() on the open database. Now, in SQLite with WAL and synchronisation NORMAL if that happens that data that was written in the write call is written to the WAL file, however since checkpoint isn't done on every step the info in the WAL will be written to the database file next time it's opened. However in unqlite when the program terminate without unqlite_close() there is a just a 512-byte large journal file and it's mostly filled with zeros. In other words the data wasn't written there. I thought it was supposed to be ACID compliant. And I haven't set UNQLITE_OPEN_OMIT_JOURNALING or any other non-standard setting.