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Subject: | Question about CA event (i.e. monitor) time order |
From: | Dirk Zimoch <[email protected]> |
To: | EPICS <[email protected]> |
Date: | Thu, 05 Jul 2012 17:21:55 +0200 |
Hello,Consider a client that subscribes for two PVs (here in particular two fields of the same record). Now the IOC (the record support) posts events on both fields. Is the time order of these two events preserved?
In other words, are the monitor callbacks of the client called in the same order as the IOC calls db_post_events()?
In my particular case, I have a client (with unknown source code) that sometimes sees value changes on two fields of the motor record, DMOV and RRBV, in the wrong order. Thus in the DMOV callback, RRBV still has the old value. I checked in the motor record that DMOV is always posted after RRBV.
Is there any mechanism in EPICS that could swap the execution order or should the problem be searched in the client?
Dirk