Re: Address of Variable in Service Program Exported Procedure

It's hard to tell what the business problem is, so this is generic advice.

One reason for a service program is to keep variables that are inside
the service program isolated from outside callers.
One can defeat this with EXPORT and IMPORT but I never, ever do this:
not even once.

If the outside needs to know something about the inside of a service
program, make it a parameter.
One way to do that is to make a SET and GET subprocedure which lets a
caller change and inspect internal variables. One synthetic example:

service program
// service program global variables
dcl-s files_opened ind inz(*off);
...
if files_opened = *off;
open file1;
open file2;
files_opened = *on;
endif;

Say a caller has some reason that it needs to know the value of
files_opened. I'd make a GET subprocedure and add it into the service
program:

dcl-proc getFiles_opened export;
dcl-pi *n ind;
end-pi;

return files_opened;
end-proc;

Now when the caller wants to know if the service program has files
opened or not, it does:

dcl-s sp_files_opened ind inz;
sp_files_opened = getFiles_opened();

The caller can't mess about with internal variables in the service
program, and it doesn't need to know anything about how the service
program maintains internal state.
--buck

On Mon, 7 Nov 2022 at 09:53, Vinay Gavankar <vinaygav@xxxxxxxxx> wrote:

Hi,

We have an exported procedure in a Service program (RPG) which needs to
pass back the address of a variable, so that the calling program can
use the value in that variable.

Can the calling program (RPG) access the value of the variable if it is
defined within that exportable procedure, or does the variable need to be
'global' in the Service Program?

TIA
Vinay
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