EPICS Home EPICS Controls Argonne National Laboratory

Experimental Physics and
Industrial Control System

Format page
for printing


Search Tech-talk
2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  <2018>  2019  2020  2021  2022  2023  2024  Index 2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  <2018>  2019  2020  2021  2022  2023  2024 
<== Date ==> <== Thread ==>
Subject: Normative types (again...)
From: Timo Korhonen <[email protected]>
To: EPICS Core Talk <[email protected]>
Date: Fri, 13 Apr 2018 14:52:08 +0000
Hi,

Everybody's favourite topic again.

I was checking some BOY screens and comparing the behaviour when switching from CA to PVA provider.
I noticed that with PVA provider the precision field is not obeyed whereas CA provider behaves like in the good old days.

Now, starting to track what is going on, I went to the Normative Types document and found the following sentence in the description of "display":

format
A format for converting the value field to a string Needs work: What is display.format? What's it for and what are examples? If it's a sprintf pattern, which syntax must it conform to - C or Java?

Looks like undone homework...

In addition, the scalar/scalarArray types have the metadata fields (alarm/time/display/control) as optional. 

I do remember the discussions around this, even if only vaguely. I believe the intention here was to mimic CA behaviour where on defines the dbr type when calling ca operations (get/put/subscribe).

Two questions:
-does the PVA API still work like this? Does e.g., qsrv deliver the display field if a PVA clients asks for it?
-has the format field (as above) been defined in the mean time and I have missed the discussion? This looks rather unlikely but maybe.

I am sorry if this has already been discussed and clarified; in that case it just has not made its way to BOY/DiiRT or where it may be handled.
Or is this still an open issue? In that case I am afraid the Types and their behaviour/semantics has to be revisited. I know how much everybody loves these discussions...

Timo

Replies:
Re: Normative types (again...) Kasemir, Kay
Navigate by Date:
Prev: Re: EPICS R3.15.5 Patches slated for the "Known Problems" Page. Williams Jr., Ernest L.
Next: Re: Normative types (again...) Kasemir, Kay
Index: 2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  <2018>  2019  2020  2021  2022  2023  2024 
Navigate by Thread:
Prev: Re: pvaccess and Java 9 Re: PVA Java status Eric Berryman
Next: Re: Normative types (again...) Kasemir, Kay
Index: 2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  <2018>  2019  2020  2021  2022  2023  2024 
ANJ, 13 Apr 2018 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·