MIDL2308
The documentation lists this name without a value.
Documented in Win32
calling conventions other than __stdcall or __cdecl not supported for /Oi modes, using /Os Calling conventions such as __pascal or __fastcall change the format of the stack. The /Oi modes only support the __stdcall and __cdecl calling conventions. If you must use other calling conventions, use the /Os mode.