Experimental Physics and
Industrial Control System

Benjamin Franksen <[email protected]> · Mon, 04 Nov 2002 13:04:39 +0100

Redman, Russell O. wrote:
> 
> It might also be worth stating explicitly whether pvPutComplete waits for
> the record to finish processing, or just for the put operation to complete
> (I am guessing the latter).

You guessed wrong.

PvPutComplete is based on the ca_put_callback facility of CA.
Ca_put_callback does not only wait for the 'put operation to complete',
i.e. the writing of the new value to the target field is done, but
instead it waits until *all* record processing caused by this put
operation is completed. This may include processing of any number of
records connected by DB links.

For instance, if the target record gets processed and has its FLNK (not
CA) pointing to a second record, pvPutComplete will not return until
*both* records finish processing. If the second record's OUT link is a
DB link to a third record and has the PP flag set, then pvPutComplete
also waits until the third record finishes processing. And so on.

Note, however, that a CA link will break this chain. This is very
similar to the way lock sets are calculated. I believe it is safe to
state that the set of records that must finish processing before a
ca_put_callback issues the callback is a subset of the target record's
lock set.

Ben

PS: I agree completely and verbatim with your proposed additions to the
manuals.
-- 
Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung
(BESSY) GmbH, Control System Group
Albert-Einstein-Straße 15, 12489 Berlin, +49 30 6392 4862, www.bessy.de

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System