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<== Date ==> <== Thread ==>

Subject: Re: More than four char's in a field name
From: Marty Kraimer <[email protected]>
To: [email protected]
Date: Tue, 06 Oct 1998 10:25:56 -0500
Rosemary Alles wrote:
> 
> Aloha,
> 
> Does EPICS 3.13 permit more than four chars for record
> field names when designing a new record?  Does this require
> changing the value of FLDNAME_SZ defined in dbDefs.h?
> 
> The following comment seems to indicate that more than
> four chars for a field name is *not* possible. (The comment
> is from dbDefs.h)
> 
> ./dbDefs.h:/* FLDNAME_SZ must be 4 */
> ./dbDefs.h:#define      FLDNAME_SZ      4       /*Field Name Size               */
> 
> I have been able to compile a record with field names greater
> than 4 chars but am concerned that other utilities within EPICS
> might not be compatible with this change.

Most ioc code has been changed to allow > four character field names.
There are a couple of places that still need to be changed.

I fell very uncomfortable about allowing this or longer length record
names until CA allows arbitrary length strings. The 40 character length
will cause subtle problems. For example:

If a client dynamically changes a soft link the string looks like:

n234567890123456789012345678.fnam NPP NMS

This is already > 40 characters (actually 42 characters with null
terminator). iocCore actually takes care of this problem. If either
field of record names are allowed to be larger it no longer possible to
fix the problem.

Marty Kraimer

References:
More than four char's in a field name Rosemary Alles

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