1. open the cursor - isc_dsql_execute2()
2. do fetch - isc_dsql_fetch()
3. closing the transaction - isc_commit_transaction()
4. do fetch - isc_dsql_fetch()

IB error code: isc_dsql_cursor_not_open (336003095)
IB error message: "Cursor is not open"

this is correct, but then follows:

SQL error code: -502
SQL error message: "The cursor identified in an OPEN statement is already open"