Re: EPICS Device Driver question

[Andrew Johnson <anj@aps.anl.gov>]

Hi David,

David Dudley wrote:
> From the talk on Device Support is says that the DSET - initialize
> routine, when passed a parameter of 1, "Can be used as a final
> startup step.  All device address information is now known."
>
> Does this imply that once the iocinit() routine has called the
> initialize routine with the parameter of 1, I can infer that no
> additional I/O items could be defined?

Unless you're providing the ability to change addresses at runtime (by 
implementing Extended Device Support, see the R3.14.8.2 iocAppDevGuide 
section 12.5 for details) the answer is yes.  The full initialization 
order for a device support is

1. For all dsets, call dset->init(0)
2. For all records, call rset->init_record(prec, 0) which in turn calls 
dset->init_record(prec, 0)
3. For all records, if a dsxt was registered call dsxt->add_record(prec)
4. For all records, call rset->init_record(prec, 1) which in turn calls 
dset->init_record(prec, 1)
5. For all dsets, call dset->init(1)

If you don't register a dsxt during your dset->init(0) call then it is 
not possible to change the record's INP/OUT field at runtime so your 
inference would be correct.

- Andrew
--
There is considerable overlap between the intelligence of the smartest
bears and the dumbest tourists -- Yosemite National Park Ranger