Re: Program performance using File Status Data Structure

[bmorris@xxxxxxxxxx]

>Date: Fri, 06 Oct 2000 18:48:22 +0200
>From: Carel Teijgeler <teygeler@bart.nl>
>
>BEllis@oriental.com wrote:
>
>> Does anyone know if it slows down program performance by including a
File
>> Status Data Structure within the F-Specs?
>> ...
>It doesnot make any difference. the information is always available in a
>programme at run-time.
>Using a datastructure makes that information accessable.

Carel (and Brian), the beginning of the INFDS is always kept up to
date whether or not you actually code the INFDS.  The open, io, and
device-specific feedback areas are only copied if the declared
length of the INFDS is big enough.  (The formatted dump uses the
"real" feedback areas, not the INFDS versions, so it doesn't need
to keep these up to date for its own purposes.)  This applies to
RPG IV - I can't remember if RPG III does the same thing or not.

But the time to copy a few hundred bytes is so small compared to the
other activities in an I/O operation that I don't think its worth
worrying about.  Even if you're not using the INFDS in your program,
it's often convenient during debugging if the INFDS is present.

Barbara Morris


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