Cython compiled C extension: ImportError: dynamic module does not define init function

Likewise a late answer... but I kept finding my way back to this question in particular. It probably is related to the mismatched names issue that Dologan addresses.\n\nWhat happened in my case was that I was adapting an example I'd gotten to work, and got the module does not define init function error. This was verified by using (e.g.)\n\n\n nm -m build/lib.macosx-10.9-x86_64-2.7/myproj.so\n\n\nIn this command's output I searched for 'init' and found\n\n\n 000000000000c0d0 (__TEXT,__text) external _initexample\n\n\nI had removed all instances of 'example' from my setup.py and .pyx file, but this persisted even after removing the extension from site-packages, removing the build and dist folders, etc. I finally found that the .cpp file being generated from my .pyx file was still referring to the class name in the example. Once I reran my setup.py, import works, and indeed the .so file includes\n\n\n 000000000000c0a0 (__TEXT,__text) external _initmyproj\n",

I've also ran into this problem. Make sure that your Cython file contains at least one of the following:\n\na normal Python def\na normal Python class (not cdef class)\na line of Python initialization, eg. a=None or a logger load\n\nOtherwise Cython won't generate a PyInit routine needed to load the module, and as such the module won't be importable by Python.",

I had the same error and was solved by running the main .py script in \"Execute in a dedicated console \" mode. Available in Tools - Preferences - Run.",

This is solved by adding a doc-string to your functions.",

I've found that a frequent cause of this problem is, when using a distutils setup file to compile the code, that the .pyx base name does not match the extension name, e.g:\n\next = Extension(name='different', sources=['cython_ext.pyx']) # Won't work\n\n\nTo avoid the problem the extension name should be exactly the same, in this case, cython_ext.",

It appears that it's a bug/feature in Cython. I had the same thing, but simply added:\n\nSTUFF = \"Hi\"\n\n\nto the top of my .pyx file and the issue went away. It appears if there is no global initialization (a cinit or setting a global variable), that the required initialization code isn't generated.",

This is a very late answer - but I just had the same error, and mine went away when I used __cinit__ instead of __init__. I'm still learing about extension types so currently I do not know why this happens. :) (You can take a look at http://docs.cython.org/src/reference/extension_types.html#initialization-cinit-and-init) Hope this is useful to someone.",

Another really late answer in my case I had accidentally called cython in a terminal that was running python2, while trying to use the generated library from a terminal that was on another python environment, using python3.\n\nUsing the same python version everywhere fixed it.",