Martijn,

> I must say I've failed to follow the existing UDF argument
> mechanisms...
>
> From what I understood, Firebird 1 supports the "By Descriptor" output
> argument mechanism. But does it also support this:

FB 1.0 supports BY DESCRIPTOR for input arguments.

> DECLARE EXTERNAL FUNCTION DPOWER
> DOUBLE PRECISION BY DESCRIPTOR,
> DOUBLE PRECISION BY DESCRIPTOR,
> DOUBLE PRECISION BY DESCRIPTOR
> RETURNS PARAMETER 3
> ENTRY_POINT 'power' MODULE_NAME 'fbudf';

RETURNS PARAMETER <N> was supported for years. BY DESCRIPTOR is supported
since FB 1.0.

> Or is this Fb 1.5?

Nothing was changed in FB 1.5.

> If input parameters support BY DESCRIPTOR, what other
> mechanisms do they support? By Value/Ref, Free It? Etc?

Input parameters are passed by reference only. FREE_IT is not applicable to
them.


Dmitry