Re: Creating UDFs

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

Robert,

It's not quite as straightforward as it seems...   When you run CREATE 
PROCEDURE to create an external UDF (i.e. one that calls an RPG or other 
HLL program) it does not actually create an object on disk. It just 
creates a definition inside the database of how to call your RPG 
program/srvpgm.

However, you do have the option to specify a library on the CREATE 
PROCEDURE statement.   CREATE PROCEDURE MYLIB/MYPROC...   If 
unspecified, it uses *CURLIB, like most all IBM-supplied create 
commands.  The library you give here is also saved to the definition 
inside the database.

When you call a procedure, it can search *LIBL (or your SQL PATH, etc) 
but it does this by looking inside the special IBM supplied PF -- which 
is a little hard to understand at first, but basically instead of 
searching for an object on disk by library list, it searches the SQL 
Table looking for a matching procedure.  For example if your library 
list is LIB1, LIB2, LIB3, then it looks in the PF for a procedure under 
LIB1 first, if not found it looks under LIB2, and if still not found, it 
looks under LIB3 -- so even though it's searching records in a file, it 
searches them as if searching a library list.

And the definition that it finds in that file is subsequently used to 
find/call your RPG routine.  (This definition could potentially also use 
*LIBL, so you end up searching the library list twice -- but that is not 
recommended.)


On 8/2/2013 9:11 AM, Robert Mullis wrote:
> I am trying to create my first UDF to use in embedded SQL in an RPGLE
> program.  I have created the procedure in a service program with no
> problem, but I have a question about the UDF.  When the UDF is created,
> what library is it created in?  Also, if the service program that the
> UDF uses is moved to another library, what happens to the UDF?  Does it
> move to the new library with it?
>
>
>
> Thanks,
>
> Robert J. Mullis