Re: EPICS database Feature request

["Pearson, Matthew R." <pearsonmr@ornl.gov>]

Hi,

If you know the record will be there when you build the db, you could do this via MSI with an optional macro passed into the template db file. e.g.:

$(COMMENT=#) record(ao, "myAO") {
$(COMMENT=#)    field(VAL, "21")
$(COMMENT=#) }

Then just uncomment it when you build the db, by passing in "".

Or, you could have some extra records that are able to change those fields at runtime?

record(stringout, "myPV:ChangeFLNK") {
  field(VAL, "AnotherAO")
  field(OUT, "myAO.FLNK CA")
}

record(stringout, "myPV:ChangeFLNKBack") {
  field(VAL, " ")
  field(OUT, "myAO.FLNK CA")
}
 
Cheers,
Matt



On Jun 6, 2014, at 11:22 AM, Emmanuel Mayssat <emayssat@epicsqt.org> wrote:

> Hello all,
> A feature I use a lot with my db  file is overwriting a record, ie:
> 
> record(ao, "myAO") {
>    field(VAL, "20")
>    field(DRVH, "40")
> }
> 
> and later in the same or another db file
> 
> record(ao, "myAO") {
>    field(VAL, "21")
>    field(FLNK, "AnotherAO")
> }
> 
> The above is equivalent to  1 single entry with
> 
> record(ao, "mAO") {
>   field(VAL, "21")
>   field(DRVH, "40")
>   field(FLNK, "AnotherAO")
> }
> 
> 
> Now the issue is that to overwrite the field of a record, you need to know its type (i.e. ao) as you need to repeat the record line.
> Is it possible to have a database entry (maybe like the alias entry) where you could just say:
> 
> changefield("myAO", VAL, 21)
> 
> which doesn't create the record if it doesn't exist, but which perform the equivalent to 
> 
> record(ao, "myAO") {
>   field(VAL, "21")
> }
> 
> if it does.
> 
> Maybe a similar command already exist.
> If so let me know,
> --
> Emmanuel
> 
> 
> 
> 
>