RE: VARLEN field... what good are they?

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

Hello Brad,

RTFM :)  Make it 5,0 as in five integer digits = 2 bytes.  For example

 D                 DS                      
 D MHDATA                     31002        
 D  MHDATALen                     5I 0     OVERLAY(MHDATA)
 D  MHDATAText                31000        OVERLAY(MHDATA:3)

Avoid From and To coding in RPG IV unless you have a REALLY good reason.

The problem is not the allocated size of storage (the 2 bytes) but RPG's 
peculiar 
interpretation of binary -- which admittedly is consistent with the database's 
view of binary 
data types.  Defining the field as binary puts the sign in the left-most bit 
instead of the 
right-most (for packed) or the high 4-bits of the right-most byte (for zoned).

RPG allocates 2-bytes for binary fields with 1 to 4 digits and 4 bytes for 
binary fields with 
5 to 9 digits.

RPG limits 2-byte binary numbers to a maximum value of 9999 instead of the 
expected 32767 (for 
signed and 65535 for unsigned).  It limits 4-byte binary numbers to 999,999,999 
instead of the 
expected 2,147,483,647 (and 4,294,967,295).  RPG behaves this way because it 
using decimal 
numbers internally and assigns a length of 4 to 2-byte binary numbers and a 
length of 9 to 
4-byte binary numbers regardless of the actual amount of storage used thus 
truncation of the 
most significant digit can occur.  This makes using real integer fields such as 
those in the 
file feedback area, API parameters, and VARCHAR structures much harder than it 
needs to be.

The major difference between Binary and Integer data types is that Binary 
fields can support a 
decimal point.

This is, of course, all described in the RPG Programmer's Reference under 
Numeric Data Type.

In most cases with RPG IV replace all Binary definitions with Integer 
definitions and life 
with be much simpler for you.

Regards,
Simon Coulter.

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//--- forwarded letter -------------------------------------------------------
> X-Mailer: Internet Mail Service (5.5.2448.0)
> Date: Tue, 18 May 99 08:09:32 -0500
> From: "Stone, Brad V (TC)" <bvstone@taylorcorp.com>
> To: "'shc@flybynight.com.au'" <shc@flybynight.com.au>
> Subject: RE: VARLEN field... what good are they?

> 
> Simon,
> 
> Thanks for the tips.  When I declare the field as integer, what size can I
> make it?  If the field is 2 binary, how can it be any larger?
> 
> The %trim(%len(xx)) was a typo... sorry.  
> 
> 
> Bradley V. Stone
> Taylor Corporation - OASIS Programmer/Analyst 
> bvstone@taylorcorp.com

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