SO module found by Cython not found by Python3

Question

I have a simple pyx file:

$ cat helloworld.pyx
print("hello world in pyx file to be converted to so file by cython.")

I have created an .so module using Cython. The directory contains following files:

$ ls -ltrh
total 140K
-rw-r--r-- 1 cardio cardio  177 Jul  3  2018 setup.py
-rw-r--r-- 1 cardio cardio   73 Jul  3  2018 helloworld.pyx
-rw-r--r-- 1 cardio cardio  74K Jul  3  2018 helloworld.c
-rwxr-xr-x 1 cardio cardio  52K Jul  3  2018 helloworld.cpython-35m-x86_64-linux-gnu.so
drwxr-xr-x 2 cardio cardio 4.0K Sep 10 20:21 __pycache__

However, when I try to import this module, I get error:

$ python3 -c "import helloworld"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'helloworld'

Where is the problem and how can it be solved?

Edit: The.so file was created in 2018, On recreating it again. everything is working perfectly! Probably there was some version conflict between Cython and Python.

Answer 1

Most commonly the reason why you can't import a module is that python doesn't see it in the location it is looking at sys.path .

You can verify this by going to the same location as the produced helloworld module, or by including it in the paths by force sys.path.insert(0,os.getcwd()) can be a current directory or a relative/absolute path .

I seem to notice a setup.py , have you tried installing this with pip install. while being in that folder, after which trying to use it?