Experimental Physics and
Industrial Control System

Hi all,

 

I have been using CA and PVA clients in Python for some time, but in the last few days I started to have issues. I recently updated to macos Catalina and python 3.7.7, and I am using epics base 7.0.4.

 

I wrote a small script to reproduce my issues:

import time

from __future__ import print_function

import epics

import p4p.client.thread

 

pv = epics.PV('SOME:PV', connection_callback=lambda pvname,conn,pv: print('connected'))

time.sleep(1)

pv.connect(timeout=0)

pv.get()

 

This script fails to connect to the PV if I run it on python 3.7.7, using pyepics 3.4.2 with PYEPICS_LIBCA pointing to epics base 7.0.4, and p4p 3.5.1. Even trying to stop the python interpreter with ctrl-C doesn’t work, I have to kill the process. Removing the p4p import fixes the issue.

I tried different EPICS7 releases and all fail, while EPICSv3 seems to work just fine. Unsetting PYEPICS_LIBCA also works, because the internal ca lib is 3.16.

It also runs fine on python 2.7, with and without PYEPICS_LIBCA pointing to epics base 7.

 

Any clue where the issue might be? Thanks!

 

Best regards,

Juan

Python 3.7.7 (default, Mar 23 2020, 17:31:31)
[Clang 4.0.1 (tags/RELEASE_401/final)] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
Imported history from '/Users/Newville/.pyhist'
>>> import os
>>> os.environ['PYEPICS_LIBCA'] = '/Users/Newville/opt/anaconda3/lib/python3.7/site-packages/epicscorelibs/lib/libca.7.0.3.99.4.dylib'
>>> import epics
>>> import p4p
>>> import p4p.client.thread
>>> epics.caget('13IDA:m1.VAL')
-0.25
>>> epics.ca.libca
<CDLL '/Users/Newville/opt/anaconda3/lib/python3.7/site-packages/epicscorelibs/lib/libca.7.0.3.99.4.dylib', handle 7fe3ceeada70 at 0x7fe3ceb7c6d0>
>>> pv = epics.PV('13IDA:m2.VAL', connection_callback=lambda pvname,conn,pv: print('connected'))
connected
>>> pv.get()
0.8

--Matt