Re: How can I Improve this procedure... -- RPG400-L

can you elaborate on this? I keep hearing it very often but did not findmuch explantation as to why?

Because a return value copies the data from one place to another. So ifyou return 3000 bytes, the system has to copy all 3000 bytes from oneplace in memory to another place in memory.

By contrast, when you pass a parameter (unless you use the VALUE keyword)the system references the existing copy of the data in memory. It doesn'thave to copy it from one place to another, it just uses the original spot.

Is this the case with procedures too? Also is it any different if theprocedure is in a service program?

Since programs can't return a value, this discussion ONLY applies toprocedures, and that's what we've been talking about all along. Unless I'mmisinterpreting the question?

No, it doesn't matter if the procedure is in a service program. (oranywhere else) This has to do with how parameters and return values work.It doesn't matter where the procedures are located.

Is it not just a pointer that is returned? Any pointers to books/IBMresources on this topic will be helpful too.

No, it is not a pointer that's returned. I'm sure that there are IBMresources that explain this, but I don't know what they are off the top ofmy head. I learned this stuff years and years and years ago, and I'mafraid that I can no longer remember where I originally learned it.

However, if the problem is that you don't believe me, you can wait untilan IBMer on the list replies.

      D                 DS
      D ReasonDS                            dim(200)
      D  @RsnCode                      2A   overlay(ReasonDS:1)
      D  @Charge                       9P 2 overlay(ReasonDS:*NEXT)
      D  @Weight                       9P 0 overlay(ReasonDS:*NEXT)
      D  @Units                        7P 0 overlay(ReasonDS:*NEXT)

[SNIP]


In this case does RPG allow  %lookup('XX': @RsnCode)  ?  I guess not as
@RsnCode is not an array.

Sorry, @RsnCode *is* an array, and yes you can use %lookup() on it.That's the reason I suggested this technique. The reason that it's anarray is because it's overlaying ReasonDS which is an array.


[SNIP]

      D ReasonDS        ds                  qualified dim(200)
      D  @RsnCode                      2A
      D  @Charge                       9P 2
      D  @Weight                       9P 0
      D  @Units                        7P 0

[SNIP]

This is exactly what I meant to do, but for the lack of %lookup support.
Would it be possible to write a generic procedure, you can pass an array
(could be an array of datastructure) that could look up this array... I am
just thinking loud here.

You could write a subprocedure that loops through it and compares theelements. That way, you can call that subprocedure to do a lookup.

Alternately, you could use the qsort() and bsearch() routines from the ILEC runtime. This has been discussed many times before, so searching thearchives should yield some examples.

Of course, the overlay approach allows you to use %LOOKUP so you might noteven want to use the qualified DIM DS approach. I'm just telling you whatyour options are.