Hi Charles,
thank you. Now I understand. And creating an executable with RTL64.inc and commenting out the cdecl calling convention worked very fine. But before I continue trying out the 64bit possibilities, I will have to set up my Win 10 notebook a little bit. At the moment I feel uncomfortable with it.
Out of curiosity: as FreeBasic 1.05 exits for 64-bit systems too, would it be also possible to create oxygen.dll for x64 systems? I did not even try to spy at the source code of Oxygen, and I will not do this until I understand at least more of Oxygen's provided include files.
Roland