py.os.popen error under Windows

Later matlab versions can call python libraries directly. I came across a problem when calling py.os.popen or py.subprocess.check_output. From the error message below, os.popen() seems calling subprocess:

h = py.os.popen('dir');

Error using subprocess>_make_inheritable (line 948)
Python Error: OSError: [WinError 6] The handle is invalid

Error in subprocess>_get_handles (line 898)
            p2cread = self._make_inheritable(p2cread)

Error in subprocess>__init__ (line 665)
         errread, errwrite) = self._get_handles(stdin, stdout, stderr)

Error in os>popen (line 978)
                                bufsize=buffering)

More info about the system: Matlab 2017a under Windows 7, python 3.6.

There is no error under Linux with python 2.7.6, matlab R2015a.

Answer 1

[Nagarjuna Manchineni]

To call Python libraries from MATLAB, you need to install a supported version of the reference implementation (CPython) for Python. MATLAB R2017a supports versions 2.7, 3.4, and 3.5.

I tried the same command on MATLAB R2017a with Python version 3.5 and everything worked fine. I would recommend to use the supported version of Python (3.5).

See the following documentation page for more reference:

https://www.mathworks.com/help/matlab/getting-started-with-python.html

[Xiangrui Li]

Thanks for answering. But that does not seem to be the cause. Could something else be wrong on my Windows 7 system?

disp(pyversion)
 3.5

h = py.os.popen('dir');
 Error using subprocess>_make_inheritable (line 913)
 Python Error: OSError: [WinError 6] The handle is invalid
   Error in subprocess>_get_handles (line 863)
              p2cread = self._make_inheritable(p2cread)
   Error in subprocess>__init__ (line 640)
           errread, errwrite) = self._get_handles(stdin, stdout, stderr)
   Error in os>popen (line 1035)
                                  bufsize=buffering)

[maho]

Having the same problem on python 3.7