Re: Subfile reversing display

[Simon Coulter <shc@xxxxxxxxxxxxxxxxx>]

On 31/03/2009, at 4:41 AM, Blake.Moorcroft@xxxxxxxxxx wrote:

> This subfile procedure is used in a number of programs.  I use it  
> any time
> we need a subfile - basically cloned code.  None of the other programs
> that use this code are having the same issue - there are around 40
> different programs using it.  The logical that is used during the  
> fill of
> this particular subfile is not unusual - a three key index with  
> ascending
> controls on the keys - there are no omit or select functions.  I have
> checked the logical to verify the index properties.

I've read all the various comments on this problem. Let's see if this  
is an accurate summary. Correct any wrong presumption:

o You have 40 programs that share the same subfile handling code.

o The subfile are SFLPAG=SFLSIZ

o You have generic code that handles both page-up and page-down

o In 39 programs the output on paging backwards through the file is  
correct but in this one it is reversed.

o Debug shows that you read the expected records.

o Your code does the following:
	- read 1st record from file and add to record 1 in subfile
	- read 2nd record from file and add to record 2 in subfile
	- . . .
	- read 10th record from file and add to record 10 in subfile
	- subfile is now full so you display it
	- user presses page down
	- clear the subfile
	- read 11th record and add to record 1 in subfile
	- read 12th record and add to record 2 in subfile
	- . . .
	- read 20th record and add to record 10 in subfile
	- subfile is now full so you display it
	- user presses page up
	- clear the subfile
	- position to record 10 (i.e., current=20 minus size=10)
	- read 10th record and add to record 10 in subfile
	- read 9th record and add to record 9 in subfile
	- . . .
	- read 1st record and add to record 1 in subfile
	- subfile is now full so you display it

The problem is the instead of 10th record being in record 10 it is in  
record 1 and each file record follows it thus the subfile is in  
reverse sequence.

If this is an accurate representation of the processing and result  
then the problem is likely due to an un-initialised subfile. I expect  
that the original code is depending on the use of SFLRNA. This keyword  
is either:
	o specified in the DDS for the working 39 programs and omitted from  
yours
	o specified in your DDS but conditioned off
	o specified and conditioned on but you've incorrectly mapped display  
file indicators to named indicators and are not actually setting it on.

If it appears that SFLRNA is specified and activated correctly then  
the likely cause is that your decrementing loop counter is not  
correctly mapped to the SFILE variable.


Regards,
Simon Coulter.
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