Experimental Physics and
Industrial Control System

On 02.12.2016 15:30, Matt Newville wrote:
> But, to summarize the earlier suggestions: if you are embedding pyepics in
> SNL,  you might need to create a new CA context in the python script with
>     import epics
>     epics.ca.context_create(0)

Hi Matt

I may be wrong but I think this is what already happens (implicitly).
The problem is that the newly created context replaces (overwrites) the
old one and then (afterwards) channels created against the old context
fail to work.

My suggestion (to repeat) is to use ca_current_context to get the
existing CA client context on startup (so that you don't overwrite the
existing context with a new one) and to somehow convince the Python
binding to NOT call ca_context_destroy when it exits. For this you could
perhaps use ca_detach_context before Python shuts down (to avoid killing
the existing context) but then you would have to save and restore the
context inside the SNL code. However, perhaps the shutdown is not really
a problem because the Python runtime system is kept alive all the time?
(I.e. as long as the SNL is running) In that case, simply ignore shutdown.