Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Wed, 06 Sep 2006 09:53:36 -0500

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. 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.
The code that implements this is dbPut() in src/db/dbAccess.c which
should be reasonably easy to follow.
- Andrew
--
There is considerable overlap between the intelligence of the smartest
bears and the dumbest tourists -- Yosemite National Park Ranger

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System