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<== Date ==> <== Thread ==>
Subject: Re: Stream device - general concept how to use
From: Ralph Lange via Tech-talk <tech-talk at aps.anl.gov>
To: EPICS Tech Talk <tech-talk at aps.anl.gov>
Date: Thu, 16 Jul 2020 18:31:24 +0200
On Thu, 16 Jul 2020 at 17:56, Christian Pauly via Tech-talk <tech-talk at aps.anl.gov> wrote:
[...]
Connecting all the get-records together via forward-links sounds a bit
unpractical for maintenance.
Maybe then its better to use a single (or nested if one is not enough)
Fanout records for regular scanning of all status-records ?

Soft event scanning is your friend for such cases. No fanouts needed.
Or just set all SCAN fields to the same value. Why do you need this to be linked?
 
I am still wondering why there is nothing foreseen to get prompt
execution of a record (and its protocol) once its read via caget (prior
to returning the result).
This would be similar to the PP ProcessPassive flag mechanism when using
input links.

Your record processes asynchronously. The PP mechanism on input links does the same thing as Channel Access: return the current value. Your input link causes the record to process, but always returns the old value.
Asynchronous processing can take any time between pretty fast and never to complete. Waiting that long is not acceptable in database processing (and not nice for a CA client).

Cheers,
~Ralph

References:
Stream device - general concept how to use Christian Pauly via Tech-talk
Re: Stream device - general concept how to use Mark Rivers via Tech-talk
Re: Stream device - general concept how to use Arnold, Ned D. via Tech-talk
Re: Stream device - general concept how to use Christian Pauly via Tech-talk
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