Experimental Physics and
Industrial Control System

Stephen Pate <[email protected]> · Mon, 14 Dec 1998 18:17:20 -0700 (MST)

Dear Tim
	Thanks for your prompt answer -- I am a little confused, still...

On Mon, 14 Dec 1998, Tim Mooney wrote:

> 
> Just adding a PREC field won't do anything at all because medm doesn't
> actually look at that field.  Display precision is determined by what the
> record-support function get_precision() says when it's called and asked
> (separately) about each field medm wants to display.  PREC is just a
> convenient, standard way for the database developer or user to give
> get_precision() a default answer. 

Well, is medm (via channel access) calling get_precision() and thereby
indirectly looking at the .PREC field?  If not, why does the medm manual
explicitly mention the .PREC field as a source of information for the
display format?  It was the text in the medm manual which prompted my
question: 

"For all of the formats, the result depends on the number itself and the
precision as returned from channel access for the process variable. The
precision is typically the PREC field for the associated record." 

"Typically" is not typically a totally clear word to use, so I thought I
would poll the collected wisdom of the medm gurus about this issue.  

If adding the .PREC field is not the answer, what is?  Do I need both to
(1) add the .PREC field and also (2) change something in the record
support to make sure get_precision() is being called? 

						thanks again,
							Steve Pate

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System