Closing Files in ILE Service Programs

May 5, 2004 Hey, Ted

We’re moving all our new development to RPG IV and ILE, and as part of this process we are looking at putting our commonly used processes into service programs. Many of these functions require access to database files. For example, one function would retrieve the price of an item according to the area in which it is being sold, the date for which the price is applicable, and whether any discounts have been set up. This is quite a complicated procedure, and we want a simple function we can call that will prevent us having to code it separately each time.

We have put this calculation into a subprocedure, which uses the passed parameters to retrieve the correct information, using three files. This subprocedure then has been put into a service program, and so far, so good–the price is returned to the program. The problem becomes apparent when the calling program ends– the three files used within the service program are still open. I assume the files are open because there is no program cycle processing that will ever close them. Short of manually opening and closing these files (which I guess would be very inefficient), I can’t see any way around this problem. Am I missing something obvious?

–Simon

The files will remain open until the activation group in which they are open is destroyed. If you assign the service program and the calling programs to the proper activation groups, you won’t have to explicitly close the files.

When you create the service program, specify ACTGRP(*CALLER) to make the service program run in the caller’s activation group. This is the default setting for service programs.

Here is the key: make sure that calling programs do not run in the default activation group. The usual way to achieve this objective is by creating them to run in either a *NEW or named activation group. It’s okay to create calling programs with ACTGRP(*CALLER) if they will always run under programs that run in *NEW or named activation groups. The problem with running your service program in the default activation group is that the only way to destroy the default activation group, and thereby to close your files, is by ending the job.

There are two ways to destroy an activation group: one is to end the job that contains the activation group, and the other is to use the Reclaim Activation Group (RCLACTGRP) command.

For more information about activation groups, see “What You Should Know About Activation Groups” and “ILE Strategies.”

–Ted