I have tried this in both firebird 2.5.5 and Firebird 3.0

I have a set of c libraries loosely based on FreeUDFLib.c

I attempt to compile them and I get:

Error c:\udf\date_functions.c 108 undefined reference to _isc_decode_date@8

Error c:\udf\date_functions.c 510 undefined reference to _isc_encode_date@8

Does anyone have a clue?