Re: AW: Overloaded UDF

Hi Neill,

It does seem to me that this level of complexity is something that a managed
language shields you from.

That's the theory... You don't need to understand how this works under the covers because it's all taken care of for you. However, I've found this type of knowledge to be beneficial...

You'd be amazed at how often it comes into play.

However if I have followed this correctly, your example of the 3 parm
procedure only being passed 2 parms in an SQL UDF call the problem is that
the descriptor is not set?

Well, if the descriptor (or at least the count) had been set, you'd be able to detect the missing parameter properly. Personally, I wish IBM had made it manditory that the parameter count be included in every call to every procedure (like they did for programs).

I am guess there is a valid reason the descriptor is not set? Or has someone
been a bit lazy :-)

By default, the parameter count isn't set from Cobol or C programs. (Though, you can force it to set the count by telling it to describe the parameters) SQL followed that precedent, but didn't give you the option to describe the parameters.

By contrast, RPG always passes at least the parameter count. CL always passes full descriptors, including not just the parameter count, but descriptions of every variable.

As to why the SQL developers made that decision? We can only guess. Unless we can rope one into this conversation, it's purely conjecture.

If you find this to be especially limiting, you might file a DCR with IBM asking them to provide at least a minimal descriptor when SQL calls an external UDF. Personally, though, I don't find it to be that big of a deal. As long as you understand the problem, you can code it properly.