Re: DOW & DOU

["James W. Kilgore" <qappdsn@xxxxxxx>]

boothm@ibm.net wrote:

> I am confused.
>
> If I was going to read the file from beginning to end why wouldn't I just
> use the rpg cycle? If I am just processing a section of the file, and want
> to get out of a loop in the odd event that I am at a group that happens to
> contain the last record in a file, then this structure serves no useful
> purpose.
>

This construct exists where you are not reading the file as the 
primary/secondary
file, but the primary/secondary file needs to loop and get records.

In a batch MR process it would not be needed, but IMO, an interactive "work 
with"
process is the foremost user of this.

Example: We have a "Work with Customer" display panel which lists the active
customers.  When one chooses a customer, a "work with" type panel is displayed
that shows outstanding sales orders(among other things).  This secondary program
does a loop to build the subfile of orders.  This loop read/sfl write is our 
use.

You are correct in that only a hard core COBOL/PIC/control freek/etc.  
programmer
would use a read instead of the cycle to process a file in batch mode and not
take advantage of record blocking. But then again that's another thread. <g>



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