RE: Chain doesn't set %EOF

["Francis Lapeyre" <flapeyre@xxxxxxxxxxx>]

No, no performance hit. Just one READE, and a test.

CHAIN was not meant to set a lower limit in this manner. I always end up
rewriting these kinds of loops with a SETLL.

If performance is your worry, then check the %EQUAL bif from the SETLL and
bypass the DOU loop entirely if it's off:

SetLL(SomeKey) File;
If %found(File);
  DoU 0 = 1;
    Read (File);
    If %Eof(File) or
      SomeKey <> KeyField;
      Leave;
    EndIf;
    // Do something
  EndDo; 
Endif;

Francis Lapeyre
IS Dept. Programmer/Analyst
Stewart Enterprises, Inc.

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx]
On Behalf Of SRamanujan@xxxxxxxxxxxxxxxxxx
Sent: Tuesday, March 29, 2005 4:25 PM
To: rpg400-l@xxxxxxxxxxxx
Subject: RE: Chain doesn't set %EOF

I don't understand. This would read the entire file and could be a potential
huge performance issue depending upon the size of the file.  
Thanks,
Sudha

Sudha Ramanujan
SunGard Futures Systems
sramanujan@xxxxxxxxxxxxxxxxxx
(312) 577 6179
(312) 577 6101 - Fax


-----Original Message-----
From: Alan Campin [mailto:Alan.Campin@xxxxxxx]
Sent: Tuesday, March 29, 2005 3:38 PM
To: RPG programming on the AS400 / iSeries
Subject: RE: Chain doesn't set %EOF

My recommendation. 

SetLL(SomeKey) File;
DoU 0 = 1;
  Read (File);
  If %Eof(File) or
    SomeKey <> KeyField;
    Leave;
  EndIf;
  // Do something
EndDo;

Was told by IBM to never use a READE, always use a READ. From a Common
conference years ago.  

-----Original Message-----
From: Paul Morgan [mailto:pmorgan@xxxxxxxxxxxxxx]
Sent: Tuesday, March 29, 2005 9:39 AM
To: rpg400-l@xxxxxxxxxxxx
Subject: Chain doesn't set %EOF


Why doesn't a failed CHAIN (which sets off %FOUND) also set on %EOF?  I can
code a read loop as:

SetLL ( SomeKey) File;
ReadE ( SomeKey ) File;
DoW Not %Eof( File );
   // do something
   ReadE ( SomeKey ) File;
EndDo;

Rather that doing a SetLL/ReadE combo to start the loop it used to be
shorthand to code a Chain with:

Chain ( SomeKey ) File;
DoW Not %Eof( File );
   // do something
   ReadE ( SomeKey ) File;
EndDo;

except Chain doesn't fiddle with %EOF so this won't work.

Could do this with RPGIII.  You could put the same indicator for the CHAIN
NotFound indicator position and ReadE EndOfFile indicator position.  Any
possibility of getting Chain to set the %EOF indicator as well as the %FOUND
indicator?  Or would that break existing code?

Paul

--
Paul Morgan
Senior Programmer Analyst - Retail
J. Jill Group
100 Birch Pond Drive, PO Box 2009
Tilton, NH 03276-2009
Phone: (603) 266-2117
Fax:   (603) 266-2333







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