Question: My final goal is to compile Python C++ extension from my C++ code. Currently to get started I am following a simple example from the first steps of pybind11 documentation. My working environment is a Windows 7 Professional 64 bit, mingw-w64 (x86_64-8.1.0-posix-seh-rt_v6-rev0) and Anaconda3 with Python 3.7.4 64 bit. I have 2 files. The first one is a C++ file -- example.cpp #include <pybind11/pybind11.h> int add(int i, int j) { return i + j; } PYBIND11_MODULE(example, m) { m.doc() = "pybind11 example plugin"; // optional module docstring m.def("add", &add, "A function which adds two numbers"); }  I compile the C++ file with the following command:  C:/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/bin/g++.exe -shared -std=c++11 -DMS_WIN64 -fPIC -ID:\Users\ADAS\anaconda3\Include -ID:\Users\ADAS\anaconda3\Library\include -ID:\Users\ADAS\anaconda3\pkgs\python-3.7.4-h5263a28_0\include -Wall -LD:\Users\ADAS\anaconda3\Lib -LD:\Users\ADAS\anaconda3\pkgs\python-3.7.4-h5263a28_0\libs example.cpp -o example.dll -lPython37  The compilation result is successful and I am getting example.dll file. At the next step I run the following Python code -- example.py: import example def main(): i, j = (1, 2) res = example.add(i, j) print("%d + %d = %d" % (i, j, res)) if __name__ == '__main__': main()  And here I have got an issue. It seems the import example line does not give me any warnings or errors but the line res = example.add(i, j) gives me an error: AttributeError: module 'example' has no attribute 'add'  Under Ubuntu 18.04 I successfully compiled and run in Python the example above but in my office I have only Windows 7. Questions: what is wrong in either my setup or command line? Is it possible to fix this problem without changing current C++ compiler (mingw-w64 version 8.1) under Windows?

Answer: It is unbelievable! The problem was just the file extension of the compiled file. As soon as I changed .dll to .pyd, the Python example (example.py) is running without any issue! So the new command line is: C:/mingw-w64/x86_64-8.1.0-posix-seh-rt_v6-rev0/mingw64/bin/g++.exe -shared -std=c++11 -DMS_WIN64 -fPIC -ID:\Users\ADAS\anaconda3\Include -ID:\Users\ADAS\anaconda3\Library\include -ID:\Users\ADAS\anaconda3\pkgs\python-3.7.4-h5263a28_0\include -Wall -LD:\Users\ADAS\anaconda3\Lib -LD:\Users\ADAS\anaconda3\pkgs\python-3.7.4-h5263a28_0\libs example.cpp -o example.pyd -lPython37  Because I did some experiments with the command line arguments, I am going to check again all the compiler arguments to make sure it gives the successful result. I will let you know, if some changes are still required. Update1: According to Python3 default settings, the full extension of the compiled C++ file under Windows has to be .cp37-win_amd64.pyd. We can get the extension by terminal command: python -c "from distutils import sysconfig; print(sysconfig.get_config_var('EXT_SUFFIX'))"  That is an equivalent of the python3-config --extension-suffix from pybind11 documentation. The python3-config script is not implemented in Windows environment (at least in Anaconda3 distribution). Update2: Under Linux OS (tested in Ubuntu 20.04), the command line is like c++ -O3 -Wall -shared -std=c++11 -fPIC $(python3 -m pybind11 --includes) example.cpp -o example$(python3-config --extension-suffix)