RE: Large Return values (was Re: Variable Length Field Question)---- I'm confused

Variable length variables (defined as 'Varying' in the keywords for the
definition) can be nice to control this - but all calling programs must
use variable length arguments as well (the format is different - there
is leader bytes telling the system how long the variable actually is, so
you can't mix a variable length field with a non variable length one).

Options VarSize is nice - cause the calling program can use any field
length up to the size defined in the prototype, but the module itself
will need a way to determine how long the field is that was passed to
it. RPG has an internal API called CEEDOD that will tell you how long
the parameter is. It's more work, but more flexible for the applications
using the module because in this case any length field can be passed in.

If all the calls are between modules that are able to use a varying
length field, I think this is easiest. If you want more flexibility to
mix variable types, Options(*VarSize) gives you more options.

'Cheers

JPW 



-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Andy Hautamaki
Sent: Friday, 23 September 2005 6:02
To: RPG400-L@xxxxxxxxxxxx
Subject: Fw: Large Return values (was Re: Variable Length Field
Question)---- I'm confused


I've searched through the archives on how to do this and I'm not sure
what 
the best method (if there is one) and I apologize if an answer has
already 
been posted
already and I can't find it.......

I always pass a  fix length as a parameter between Modules. It would be
nice 
when dealing with a field that has the potential to be rather large to 
define it as a variable length. The method that Scott and Brad discuss
is 
this the best way to do this?

Thanks
Andy
----- Original Message ----- 
From: "Brad Stone" <brad@xxxxxxxxxxxx>
To: "RPG programming on the AS400 / iSeries" <rpg400-l@xxxxxxxxxxxx>
Sent: Thursday, May 20, 2004 2:35 PM
Subject: Re: Large Return values (was Re: Variable Length Field
Question)


> On Thu, 20 May 2004 13:20:36 -0500 (CDT)
> Scott Klement <klemscot@xxxxxxxxxxxx> wrote:
>>
>> [SNIP]
>> >      D ToUpper         PR            10I 0
>> >      D  InString                  32766A   Const
>> Varying
>> >      D  OutString                 32766A
>>   OPTIONS(*VARSIZE)
>> >
>> > The second parameter now becomes the target of the
>> > conversion, and the OPTIONS(*VARSIZE) allows you to
>> pass a
>> > parameter whose length is 1 to 32766 bytes. You simply
>> use
>> > %LEN(InString) inside the subprocedure to determine how
>> > much data was actually passed to your subprocedure.
>> Then,
>> > be sure to "touch" only that many characters in the
>> > OUTSTRING parameter.
>>
>
>> > 1.  Wouldn't you need to use %len(%trimr(InString))
>> because
>> > if the input parm used in the calling program is NOT a
>> > variable length field or a literal it won't be correct.
>>
>> In Bob's example, the input parm *WAS* defined as
>> VARYING.  There's no
>> need for extra work of the %trimr().  If the user wants
>> his string
>> trimmed, let him trim it himself.
>
> That's what I was getting at here.  I wasn't talking about
> the parmeter in the proc definition, I was talking about
> the field a user uses to pass into the subprocedure.
>
> If it's declared as 1024 (non-varying) bytes and only
> contains "hello" the %len(InString) in the subprocedure
> will return 1024.  That's why I suggested maybe using
> %len(%trimr(InString)) would actually produce the "desired"
> results in all cases.
>
> Yes, the user could trimr it when calling the procedure,
> but either way you have to trimr it to get the actual
> length.  Unless parm used is of varying type.  (but that's
> not always going to be the case).
>
> And since this case is for a product he sells, I guess one
> could weigh the performance vs. consumer confusion on
> whether they need to use varying, or not, or trimx it, or
> not.
>
> _______________________________________________
> This is the RPG programming on the AS400 / iSeries (RPG400-L) mailing
list
> To post a message email: RPG400-L@xxxxxxxxxxxx
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
> or email: RPG400-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/rpg400-l.
>
>