READE behavior question

[Vern Hamberg <vhamberg@xxxxxxxxxxx>]

Y'all

It's my vacation and I'm thinking odd things about RPG I/O. In 
particular, I'm trying to work out just READE really works.

The documentation says it "retrieves the next sequential record ... if 
the key of the record matches the search argument".

Now I've never thought really deeply about this, but I'm thinking that, 
in essence, it sets %eof if the NEXT record in key order does not match 
the search argument - I have tried this and believe I confirmed this. It 
doesn't jump to a matching record farther along, even if it exists.

Here is some sample data and code to demonstrate this.

F1   F2   F3
 1    1    1
 1    1    2
 1    1    3
 1    2    1
 1    2    2
 1    2    3
 1    3    1
 1    3    2
 1    3    3
 2    1    1
 2    1    2
 2    1    3
 2    2    1
 2    2    2
 2    2    3
 2    3    1
 2    3    2
 2    3    3
 3    1    1

Ftestreade IF   E           K DISK

d kDS             ds                  likerec(testreader : *key)
d iDS             ds                  likerec(testreader : *input)
 /free
  kDS.f1 = 1;
  kDS.f2 = 2;
  kDS.f3 = 1;
  chain %kds(kDS) testreade iDS;
  dsply %found(testreade);
  reade %kds(kds : 2) testreade iDS;
  dsply %eof(testreade);
  kDS.f1 = 2;
  reade %kds(kds : 2) testreade iDS;
  dsply %eof(testreade);
  *inlr = *on;
 /end-free

The CHAIN finds the record with values 1, 2, 1 - since it exists.
The 1st READE finds a record, since the NEXT record has key 1, 2.
The 2nd READE sets %eof because, although a record exists with key 2, 2 
- it isn't the NEXT record in key sequence.

As I say, I've never tried this - there may not even be a reason to do 
so, but I've done some curious things in my life. At any rate, it seems 
that the behavior is, in essence, to READ the next record and check for 
equality - not that it actually does it that way, it is just how it 
seems to come out.

Comments are welcome. I know I might be over-simplifying things, but the 
way things work down low may differ from what is the perceived result.

Happy New Year, y'all!
Vern