Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Fri, 12 Dec 2014 10:44:57 -0600

Hi,

On 12/12/2014 10:28 AM, Walter Werner wrote:
> I use pyepics for my client and want to avoid the "Virtual circuit
> disconnect" exception from CA being printed on the standard input.
> CA.Client.Exception...............................................
>     Warning: "Virtual circuit disconnect"
>     Context: "localhost:20000"
>     Source File: ../cac.cpp line 1215
>     Current Time: Wed Dec 10 2014 05:51:45.821307011
> ..................................................................
> This exception accrues if the server is down.

Do you have a connection callback handler for your PVs? If not,
supplying one may prevent some of the disconnect messages (and permit
your code to find out when it should stop trying to access the PV values).

You can also redirect any/all error messages from the underlying CA
library by providing your own printf handler. From the pyepics
documentation for the low-level CA module:

> epics.ca.replace_printf_handler(fcn=None)
>   Replace the normal printf() output handler with the supplied
>   function (defaults to sys.stderr.write())

Note that a single message like the one you quoted above may have come
from several calls to the printf handler routine, so don't just try to
pop up a new dialog box every time it gets called.

HTH,

- Andrew
-- 
People everywhere confuse what they read in newspapers with news.
-- A. J. Liebling

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System