Experimental Physics and
Industrial Control System

Dirk Zimoch <[email protected]> · Thu, 27 Jun 2013 15:16:04 +0200

Hi all,

I have an application which needs to read or write EPICS data whenever

something interesting happens with other EPICS data. The naive way would

be to do ca_get and/or ca_put inside a monitor callback function. But as

far as I remember, this is forbidden.

Is this (still) true? I cannot find anything about this in the Channel

Access Reference Manual.

If it is not (yet) possible, can this be implemented in a future release

of the channel access library? I think it is a common use case to "do

something when something else happened".

What is the best practice to do monitor triggered channel access at the

moment?

One way I can imagine is to setup a different thread blocking on an

event semaphore and release that semaphore from within the monitor

callback. But this involves thread save programming with all its

complications.

Dirk