Re: Service programs suck

David FOXWELL wrote:

Module 1 Procedure 1 calls Module 2 Procedure 1.
Module 2 Procedure 2 calls Module 3 Procedure 1.

Module 3 Procedure 1 gets the following modification : a parameter M3P1Parm that is a DS declared LIKE another DS in the same module. Module 2 Procedure 2 is modified accordingly.

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Module 3 is recompiled, no problem.
Module 2 is recompiled, the compiler imports the protoypes of all the exported procedures of Module 3 with the definition of M3P1Parm, again no problem.
Module 1 is recompiled, the compiler imports the protoypes of all the exported procedures of Module 2 : Procedure 1 that is uses, and Procedure 2 that it doesn't - PROBLEM, it doesn't know what is M3P1Parm.

Do you mean that Module 2 procedure 2 gets a new parameter that is also defined LIKEDS(M3P1Parm)? I assume that is what you mean by "Module 2 Procedure 2 is modified accordingly"

If yes, then I think that the definition of M3P1Parm should be in its own copy member, and /copied in the procedure prototype copy member for both modules 2 and 3. My rule of thumb is that procedure prototypes for exported procedures should only use LIKE definitions if those definitions are also in the copy member containing the prototype.

I suggest that Module 2 should be a service program and that Module 1 would not have to be recompiled.

This sounds like a dangerous proposition to me. What happens when you need to make a quick fix to some unrelated code in Module 1? The person doing maintenance will have to figure out why the prototypes from Module 2 are causing problems.

I am reminded that we do not use service programs as they use dynamic calls and that would mean the same as going back to RPGIII.

I'm relatively new to RPG, so I don't know what "like going back to RPGIII" means. That said, we haven't found the "bind by reference" operation of service programs to be a problem. On the contrary, it is really handy to be able to fix a bug in a service program procedure and not have to recompile all of the calling programs.