Experimental Physics and
Industrial Control System

Benjamin Franksen <[email protected]> · Thu, 7 Sep 2006 11:34:08 +0200

On Wednesday 06 September 2006 16:53, Andrew Johnson wrote:
> Benjamin Franksen wrote:
> > can the record support special() routine find out how many (array)
> > elements have been resp. are going to be written (assuming SPC_MOD
> > is set for the field and there is actually more than one element
> > etc..)? And if yes, how?
>
> No, the arguments to the rset->special() routine are the DBADDR for
> the field that is being written to, and the pass (0 before, 1 after
> the actual put operation).
>
> However if there's more than one element in the buffer and the field
> is marked as special, immediately after calling rset->special() the
> rset->get_array_info() routine is called to get the offset value (for
> appending data to circular buffers), and after changing the array the
> rset->put_array_info() routine is also called to tell it how big the
> request was.

Ha, that was the kind of trick I was hoping for. Thanks a lot.

> Unfortunately this doesn't seem to provide any way to 
> reject a put based on size if that's what you're trying to do.

No, fortunately that wasn't the goal, I just wanted to remember the 
number of elements actually written, and do some special processing 
based on that. I'll do this in method put_array_info, then, not in 
special.

Thanks again,
Ben
-- 
You've never looked into my eyes but don't you want to know
What the dark and the wild and the different know -- Melissa Etheridge

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System