Re: monitors on array variables

["Siddons, David via Tech-talk" <tech-talk at aps.anl.gov>]

.....and I have, in cvt_dbaddr():

  case zDDMRecordSPCT:{

      paddr->pfield = (void *)(pzDDM->pspct);

      paddr->no_elements = 4096; /* One spectrum for real-time display */

      paddr->field_type = DBF_LONG;

      paddr->field_size = sizeof(int);

      paddr->dbr_field_type = DBR_LONG;

      break;

Pete.

---

From: Michael Davidsaver <mdavidsaver at gmail.com>
Sent: Wednesday, March 18, 2020 12:54 PM
To: Mark Rivers <rivers at cars.uchicago.edu>; Siddons, David <siddons at bnl.gov>
Cc: EPICS Tech-Talk <tech-talk at aps.anl.gov>
Subject: Re: monitors on array variables

 

On 3/18/20 9:47 AM, Mark Rivers wrote:
>> by analogy waveformRecord has
>>> db_post_events(prec, &prec->val, monitor_mask);
>> note 'val' not 'bptr'.
>
>
> The mca record has worked with no changes in 3.14, 3.15, and 7.0.3 with these lines:
>
>
> mcaRecord.dbd:
> recordtype(mca) {
>         include "dbCommon.dbd"
>         field(VERS,DBF_DOUBLE) {
>                 prompt("Code Version")
>                 special(SPC_NOMOD)
>                 initial("1")
>         }
>         field(VAL,DBF_NOACCESS) {
>                 prompt("Value")
>                 special(SPC_DBADDR)
>                 pp(TRUE)
>                 size(4)
>                 extra("void *val")
>         }
>         field(BPTR,DBF_NOACCESS) {
>                 prompt("Buffer Pointer")
>                 special(SPC_NOMOD)
>                 interest(4)
>                 size(4)
>                 extra("void *bptr")
>         }
>
> mcaRecord.c:
>     if (MARKED(M_VAL)) db_post_events(pmca,pmca->bptr,monitor_mask);
>
> So it is posting monitors on the bptr field, not the val field, and it seems to work fine.
>
>
> It looks like Pete is doing what the mca record does, but it is not working.  Why?

Ah, there is a second piece to the puzzle.

db_post_events() must be called with whatever address is in DBADDR::pfield
which by default in this case is '&val' but this can be changed in the
cvt_dbaddr callback.  Indeed waveformRecord used to do this.

https://github.com/epics-base/epics-base/commit/92d52cc415599b7dffa7df1f23d5ba8227fb4d3a