Mixing an nidmm PXI-407x session and niswitch sessions causes unexpected failures finding the NI-SWITCH Functions on Linux
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Description
Description of issue
Using Python 3.9.15, NI-DMM 23.5 and the nidmm 1.4.5 python package, I get weird behavior when using a 407x device and mixing usage of NI-DMM and NI-SWITCH sessions (used the niswitch 1.4.5 package, but I also reproduced with the nidcpower 1.4.5 package).
Specifically after running a very small program (listed below in the steps to reproduce) that includes opening an NI-DMM session, calling dmm.initiate(), and then opening an NI-SWITCH Session, I get the following error:
Traceback (most recent call last):
File "/home/user/.pyenv/versions/3.9.15/lib/python3.9/site-packages/niswitch/_library.py", line 65, in _get_library_function
function = getattr(self._library, name)
File "/home/user/.pyenv/versions/3.9.15/lib/python3.9/ctypes/__init__.py", line 387, in __getattr__
func = self.__getitem__(name)
File "/home/user/.pyenv/versions/3.9.15/lib/python3.9/ctypes/__init__.py", line 392, in __getitem__
func = self._FuncPtr((name_or_ordinal, self))
AttributeError: /home/user/.pyenv/versions/3.9.15/bin/python: undefined symbol: niSwitch_InitWithTopology
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/home/user/./switch_reproducer.py", line 6, in <module>
with niswitch.Session(resource_name="", topology="2535/1-Wire 4x136 Matrix", simulate=True) as session1:
File "/home/user/.pyenv/versions/3.9.15/lib/python3.9/site-packages/niswitch/session.py", line 1377, in __init__
self._interpreter.set_session_handle(self._init_with_topology(resource_name, topology, simulate, reset_device))
File "/home/user/.pyenv/versions/3.9.15/lib/python3.9/site-packages/niswitch/session.py", line 1993, in _init_with_topology
vi = self._interpreter.init_with_topology(resource_name, topology, simulate, reset_device)
File "/home/user/.pyenv/versions/3.9.15/lib/python3.9/site-packages/niswitch/_library_interpreter.py", line 293, in init_with_topology
error_code = self._library.niSwitch_InitWithTopology(resource_name_ctype, topology_ctype, simulate_ctype, reset_device_ctype, None if vi_ctype is None else (ctypes.pointer(vi_ctype)))
File "/home/user/.pyenv/versions/3.9.15/lib/python3.9/site-packages/niswitch/_library.py", line 225, in niSwitch_InitWithTopology
self.niSwitch_InitWithTopology_cfunc = self._get_library_function('niSwitch_InitWithTopology')
File "/home/user/.pyenv/versions/3.9.15/lib/python3.9/site-packages/niswitch/_library.py", line 67, in _get_library_function
raise errors.DriverTooOldError() from e
niswitch.errors.DriverTooOldError: A function was not found in the NI-SWITCH runtime. Please visit http://www.ni.com/downloads/drivers/ to download a newer version and install it.
The error is clearly misleading. I shouldn't have any issues opening a session to both devices.
I am using IVI simulated devices, so no hardware is required.
If I simulate a 4081 DMM instead of a 4071, the error doesn't happen.
If I remove the dmm.initiate() call then the error doesn't happen.
If I use Python 3.10.8 then even the reproducing example as written doesn't reproduce.
I have also rewritten the example using a simulated nidcpower.Session (using a 4190), and that DOES reproduce (so I think that nidmm must be at fault).
I have found that this is very particular, and if I modify the code slightly I can stop seeing the error (move the dmm.initiate() after opening the niswitch.Session and its fine).
System report
python -c "import nidmm; nidmm.print_diagnostic_information()" output:
OS:
Name: Linux
Version: #26~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Thu Jul 13 16:27:29 UTC 2
Bits: 64
Driver:
Name: NI-DMM
Version: Unknown
Module:
Name: nidmm
Version: 1.4.5
Python:
Version: 3.9.15 (main, Aug 11 2023, 09:46:20)
[GCC 11.4.0]
Bits: 64
Is_Venv: False
Installed Packages:
virtualenv==20.24.2
setuptools==58.1.0
platformdirs==3.10.0
pip==22.0.4
niswitch==1.4.5
nidmm==1.4.5
nidcpower==1.4.5
hightime==0.2.1
filelock==3.12.2
distlib==0.3.7
Steps to reproduce issue
import niswitch
import nidmm
with nidmm.Session(resource_name="", options= { "simulate": True, "driver_setup": { "Model": "4071" } }) as dmm_session:
dmm_session.initiate()
with niswitch.Session(resource_name="", topology="2535/1-Wire 4x136 Matrix", simulate=True) as session1:
pass
Run the above code using python 3.9.15 on Linux
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the reproduced Python 3.9/Linux sequence in the issue, then inspect niswitch/_library.py, niswitch/_library_interpreter.py, and the session initialization path shown in the traceback. Compare how loading NI-DMM or NI-CPower before NI-SWITCH affects symbol lookup. Done means the reproducer can open both simulated sessions after dmm_session.initiate() without the misleading DriverTooOldError.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 30/100