I think the problem is that wcslen() expects a whar_t (4 bytes) sequence,
while SQLWCHAR is 2 bytes long.
Because I'm unsure if my code is correct, I've tested the same with
python3 and pyodbc (which uses the wide-functions, too).
This results in the same issue, so using the firebird odbc driver
with pyodbc/python3 is impossible for the moment.
Could anyone confirm this issue?