RE: Prototypes, /COPY and LIKE()

Hi Joe,

In v5r1 what you are asking for is actually doable. Here is how I do it:

1st, I have a srcmbr that contains all my prototypes, qualified data
structures, constants, ...  In that srcmbr I dcl an external ds:

d rAtm          e ds                  extname(AcfAtm) qualified

( where AcfAtm is a physical file. )

Then in the module that declares the file, I use PREFIX to add "rAtm." to
each field in the file:

fAcfAtm1   uf a E           k Disk    usropn  rename(AcfAtmr:AcfAtm1r)
f                                     prefix('RATM.')

( AcfAtm1 is a logical view of AcfAtm )

Now, all the flds of the rcdfmt are refered as flds in the qualified ds
"rAtm"
      if     rAtm.IsActive = conTrue ;
      endif ;

Here is a proc that reads a record from the AcfAtm file and returns it thru
a reference parm:

 ** ---------------------- AcfAtm_ReadLatest ---------------------
 ** AcfAtm_ReadLatest - read latest AcfAtm of SendFxid
 pAcfAtm_ReadLatest...
 p                 b                   export
 dAcfAtm_ReadLatest...
 d                 pi
 d InSendFxid                          value like(AcfRef.SendFxid)
 d OutAtm                              likeds(rAtm)
 d OutFound                        n   options(*NoPass)

 d fFound          s               n
  /free
       .....
       setgt       InSendFxid AcfAtm1r ;
       dow         conTrue ;
         readpe(n) InSendFxid AcfAtm1r ;
         select ;
         when      %eof( ) ;
           fFound    = conFalse ;
           leave ;
         when      rAtm.IsActive = conFalse ;
           iter ;
         other ;
           fFound    = conTrue ;
           OutAtm    = rAtm ;
           leave ;
         endsl ;
       enddo ;
       ......
  /end-free
 p                 e

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Joe Pluta
Sent: Tuesday, August 12, 2003 11:28 PM
To: 'RPG programming on the AS400 / iSeries'
Subject: Prototypes, /COPY and LIKE()


Okay, I'm running into an issue.  I've gotten very good about creating
modules and using /COPY to separate the external prototypes for
procedures.  This works wonderfully except for one specific situation.

Often, I like to pass a database field as a parameter.  I've learned
over the years that the best way to define such a field is by doing a
LIKE define against the actual database field.  For example:

d SccIOKWClear    pr
d   ID                                like(KWDFID) value
d   Format                            like(KWFMT ) value

This function clears all the records from the file with the two key
fields specified.  Works like a champ, provided I have defined KWDFID
and KWFMT. However, with a /COPY prototype, there's no simple way of
importing the database definitions in order to do a LIKE define against
them.

I could include an externally described data structure, but now I'm
looking at wasted storage and possible name space collisions.  Thus my
dilemma.

My current thinking is to use a based external DS with a prefix.  This
would "waste" only the space for a pointer, thus:

d __SCCKW       e ds                  extname(SCCKW) based(__)
prefix(__)
d SccIOKWClear    pr
d   ID                                like(__KWDFID) value
d   Format                            like(__KWFMT ) value

(The double underscore is just an idea; I could just as easily use a
double @ or something else to try and minimize collisions.)

Any comments?

Joe


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