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<== Date ==> <== Thread ==>
Subject: Re: Listen to multiple events
From: Korhonen Timo <[email protected]>
To: Emmanuel Mayssat <[email protected]>
Cc: [email protected], Dehong Zhang <[email protected]>
Date: Wed, 19 Mar 2008 08:59:39 +0100
Emmanuel Mayssat wrote:
On Tue, 2008-03-18 at 13:09 +0100, Korhonen Timo wrote:
set to the same number. The ai record could then look like this:

record(ai, "Test:RecordToProcessOnEvent1or2") {
field(SCAN, "Event")
field(EVNT, "1") #EVNT is the soft event number

...other ai fields here...
}

The problem with this method is that you have to keep track of the event
numbers in use. I believe epics support only 256 events. If a device
driver sends the same event ~number~ than the one expected by another
driver, then you are toasted!

Well, there is no free lunch ;-)
However, it is anyway a good idea to keep track of the events
and (IMHO) a small price to pay for the flexibility you get with that method.
The 'soft' event numbers need only to be unique per IOC. Hard coding the event
number in a driver would not be a very good idea. Usually this is done in the record level
(like the event or calcout records) so the numbers can be managed by the app developer
in the record configuration.

As Stephanie pointed out, this discussion was specific to event receivers, but of course
nothing stops one from implementing a similar method for other hardware.

best regards,

Timo


--
Timo Korhonen PSI (Paul Scherrer Institut, http://www.psi.ch) CH-5232 Villigen PSI tel + 41- 56 3103262 fax + 41 - 56 310 3383 e-mail: [email protected]

References:
Listen to multiple events Dehong Zhang
RE: Listen to multiple events Allison, Stephanie
Re: Listen to multiple events Korhonen Timo
Re: Listen to multiple events Emmanuel Mayssat
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