I am trying to use an external C++ dll and also privide call back functions to this dll to call back.
However, the dll requires my functions to return 8 byte of 'struct' via register and the dll author said it is not possible with Delphi. Is that possible with fpc?

Dennis

However, the dll requires my functions to return 8 byte of 'struct' via

register and the dll author said it is not possible with Delphi. Is that possible with fpc?

If you know the register, just assign it via inline assembly.

"Dennis Poon" wrote

I am trying to use an external C++ dll and also privide call back

functions to this dll to call back.

However, the dll requires my functions to return 8 byte of 'struct' via

register and the dll author said it is not possible with Delphi.

Is that possible with fpc?

How does the prototype of the fallback look like in C++?

Regards,
Sven

Dennis Poon wrote

I am trying to use an external C++ dll

Usually you can't use (pure) C++ DLLs. DLLS need to have a "flat" (ANSI C) interface using standard data types and calling conventions.

I suppose with x86/64 the return value in fact is 8 bytes in a single register.

AFAIK, with X86/32 there is no single register with 8 bytes.

-Michael