Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Fri, 15 Mar 2013 11:34:26 -0500 (CDT)

Hi Mark,

On Mar 14, 2013, at 7:23 PM, Mark Rivers <[email protected]> wrote:

> But I think the way the mbboDirect record works it expects the Bn fields to be the ones you initialize before the record first processes.  I don't know how that is supposed to work if your driver does not provide an initial value, and the database does not know how to define it.  Because the first time you do a caput to B1, it will also write the values of B2, B3, etc. which may not have been initialized correctly yet.
> 
> Maybe I'm missing something?

Probably not, IIRC the mbb*direct record types were not written by the EPICS core developers but by someone (I think at JLab) hacking on the mbb* records until they got something that did what they wanted without thinking about other users or uses for them. The documentation is similarly lacking and broken on the Wiki page.

In December I made some major cleanups in the code and how these records behave for the versions on the 3.15 branch, but I couldn't bring those changes back to the 3.14 branch because they would almost certainly break existing databases. For 3.14 users I recommend only using these record types for their behavior of splitting a number into individual bits or the reverse.

- Andrew

-- 
Sent from my iPad

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System