RE: Max length of a VARYING field

["Holden Tommy" <Tommy.Holden@xxxxxxxxxxxxxxxxx>]

<snip>Or instead of giving us the size of the length prefix, maybe
something 
like %addr(myVaryFld: *DATA) and %size(myVaryFld: *DATA) or 
%len(myVaryFld:*MAX)</snip>

That works too...as long as there is *some* mechanism for handling the
different prefix/index size I'm good... 


Thanks,
Tommy Holden


-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Scott Klement
Sent: Thursday, May 17, 2007 2:10 PM
To: RPG programming on the AS400 / iSeries
Subject: Re: Max length of a VARYING field

Hi Peter,

> Why VARYING(x) as opposed to VARYINGx?  The former implies (to me 
> anyway) that I can put whatever I want in there -- VARYING(1), 
> VARYING(7), etc.  Or maybe that's the intention; after all, why not?  

I prefer VARYING4, VARYING8, etc, myself.  However, Barbara said that 
they (the team at IBM) liked the parenthesis better.  here's her
message:
http://archive.midrange.com/rpg400-l/200705/msg00392.html


> Let's be flexible.  Aren't all these 2-byte, 4-byte integers simply 
> those sizes because they're closer to what the hardware can handle?

Hardware typically is able to handle 1, 2, 4 and 8 bit integers 
natively.  Note that when you define an integer in RPG (data types B, I 
and U) it must be one of those 4 sizes.   Why would the prefix be 
different?

Bearing in mind that allowing other lengths (3,5,6,7 bytes) would make 
VARYING strings significantly slower, my question to you is this:  What 
would be the advantage?  Can you think of a situation where you'd want 
to use a 3-byte prefix, but a 4-byte wouldn't work just as well?   Or a 
5 byte where an 8 byte wouldn't work just as well?  What would be the 
advantage of the other sizes?


> Later responses mention a %indexsize BIF.  Index?  It's a current
length 
> subfield isn't it?.  How about %sizelen, or %lensize or something?  
> Unless it's considered an index to the end of the string...but I think

> most people think of it as the current length, hence the %len BIF.

I think something like %varysize() or %vsize() would be better than 
%sizelen() which seems ambiguous to me.

Or instead of giving us the size of the length prefix, maybe something 
like %addr(myVaryFld: *DATA) and %size(myVaryFld: *DATA) or 
%len(myVaryFld:*MAX)