RE: EXTFILE/EXTMBR in V5R1 question

So really all this is doing is making it "Easier" to override which file you
want to use inside your RPG program.

Instead of using QCMDEXC and OVRDBF, you can use these keywords.  

I've only read the small bit of info on this in the iSeries mag, so I wasn't
quite sure.  So, I hope I got the main idea of it.  Let me know if I'm way
off still.  It wouldn't be the first time.

Brad

> -----Original Message-----
> From: Gary Guthrie [mailto:GaryGuthrie@home.com]
> Sent: Wednesday, May 09, 2001 8:42 AM
> To: RPG400-L@midrange.com
> Subject: Re: EXTFILE/EXTMBR in V5R1 question
> 
> 
> No, Brad, you won't have to do that. The external definition is
> available.
> 
> What the new keyword does is allow you to provide an external name for
> the file to open. In prior releases you could only specify 
> the internal
> name (the name in column 7 on the F-spec) and the external name was
> always the same.
> 
> Now you must still specify the internal name (works like it 
> always did),
> but you have control over whether to specify a non-default value
> (default of course being internal name) for the external name.
> 
> I'm not sure I like the function this provides, however. Sure it makes
> it easy to specify a different file name or a different member to be
> opened so that you don't need a driver CL to do so via an 
> override, but
> I think it opens the door for a bit of confusion and potential
> design/maintenance issues.
> 
> If you provide the external name using the keyword, any overrides must
> now be to the external name. This is counter to what RPG programmers
> have done for centuries. The big potential problem I see is 
> one in which
> you design an application's flow. During the design phase, 
> you know you
> want the ability to open various files depending on run-time
> considerations. You therefore use the keyword and you have a 
> convenient
> way to effect your goal. Time goes by and now all of a sudden you need
> to issue some sort of additional override to the file. This means that
> you must now, depending on your design, introduce a driver CL or
> user-open and a call to QCmdExc (or one of its cronies) to put your
> additoinal override into effect. This disrupts the general 
> structure of
> your application, and in my opinion maintenance will take 
> longer (and be
> more prone to introduce errors) than if your original design used a
> driver CL (or the user-open method) and was already set up to let you
> simply add the additional override parameters to your existing one.
> 
> I've rambled - does that make sense?
> 
> 
> Gary Guthrie
> NEWS/400 Technical Editor
> 
> 
> "Stone, Brad V (TC)" wrote:
> > 
> > I have a quick question...
> > 
> > If I use the EXTFILE keyword to define which file to open 
> at runtime in my F
> > specs in V5R1, does that mean I have to internally define 
> my fields?  I
> > would assume since this is a run-time argument that the 
> file description
> > will not be available to my program.
> > 
> > Any ideas?
> +---
> | This is the RPG/400 Mailing List!
> | To submit a new message, send your mail to RPG400-L@midrange.com.
> | To subscribe to this list send email to RPG400-L-SUB@midrange.com.
> | To unsubscribe from this list send email to 
> RPG400-L-UNSUB@midrange.com.
> | Questions should be directed to the list owner/operator: 
> david@midrange.com
> +---
> 
+---
| This is the RPG/400 Mailing List!
| To submit a new message, send your mail to RPG400-L@midrange.com.
| To subscribe to this list send email to RPG400-L-SUB@midrange.com.
| To unsubscribe from this list send email to RPG400-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---