Re: Passing unwanted parameters

Rory Hewitt wrote:

However, since the extra parameter would be a simple string, I think I *
might* simply define a UDS (data-area data-structure) in the caller, set it
to my required value and then use OUT to update it prior to calling the
programs. Those called programs that need the value can simply define the
same UDS and it's immediately available to them. The caller will
automatically create it in QTEMP and lock it, so it's effectively a CONST
parameter. Same system for RPG/400 or CL programs, I'd guess.

I'm trying to think of drawbacks to this approach... any thoughts.

RPG doesn't allow a program to lock a data area even if the lock is for the same job. So your scheme wouldn't work if one of the called programs that needs the value calls another program that needs the value.

If you do use the data area, better to use IN and OUT to avoid keeping the lock.

Another approach is to use a service program to hold the value. The caller would call a procedure to set the value, and the called programs would call another procedure to get the value. This approach has the same split-interface problem that Simon mentioned for the data area approach, but it's more extensible than using a data area.