ImportError: dynamic module does not define init function

Question

I am trying to reproduce the following tutorial https://csl.name/post/c-functions-python/ .

The extension of My Python in C ++ is as follows:

#include <Python.h> static PyObject* py_myFunction(PyObject* self, PyObject* args) { char *s = "Hello from C!"; return Py_BuildValue("s", s); } static PyObject* py_myOtherFunction(PyObject* self, PyObject* args) { double x, y; PyArg_ParseTuple(args, "dd", &x, &y); return Py_BuildValue("d", x*y); } static PyMethodDef extPy_methods[] = { {"myFunction", py_myFunction, METH_VARARGS}, {"myOtherFunction", py_myOtherFunction, METH_VARARGS}, {NULL, NULL} }; void initextPy(void) { (void) Py_InitModule("extPy", extPy_methods); } 

I use the following setup.py :

 from distutils.core import setup, Extension setup(name='extPy', version='1.0', \ ext_modules=[Extension('extPy', ['extPy.cpp'])]) 

After calling python setup.py install the .so file seems to be in the right place.

But when I try to use this extension with import extPy , I get an error:

ImportError: dynamic module does not define init function

What am I missing here? Thanks for the help.

Answer 1

Since the initextPy function is a C ++ function that forces the C ++ compiler to ignore the name so that it is not recognized.

You need to mark the function as extern "C" to prevent the name from being changed:

 extern "C" void initextPy(void) { ... }