Experimental Physics and
Industrial Control System

Jeff Hill <[email protected]> · Wed, 16 Jul 1997 16:01:01 -0600

> 
> So, I would like to propose changing the ULONG mapping to LONG, so that it
> can be fetched in native type and correctly recognized as being an integer.
> 
> Comments?
> 

My position is that mapping ULONG to LONG results in a sloppy API which
could influence existing general purpose clients to break in unexpected
ways. How can we predict what range of numbers will be used by the
EPICS community. This could result in bugs that would not easily be 
detected during operation. This is also not a backwards compatible change.

I propose that we add dbr_ulong_t and dbr_ushort_t to the CA client API.
Requests for these types would of course be refused when they are
issued to old servers.

It is also possible that we should add new DBR_XXX types that would allow the
client to determine if the PV it is attached to is analog/binary and in/out.
This would perhaps directly address the underlying cause of Chip's troubles
(he is using the native type of the PV to guess that the PV is one of
analog/binary). Matthias has requested a new DBR_XXX type that would
return the record type as a string.

Jeff

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System