PyCppDemo

Preparation

1. Set up the git repo.

2. Add essential submodules: put all 3rd party libraries in a folder, and manage them with git submoudle.

cd third_party

• Eigen

git submodule add https://gitlab.com/libeigen/eigen.git eigen
cd eigen
git checkout 3.4
cd ..

• Pybind11

git submodule add https://github.com/pybind/pybind11.git pybind11
cd pybind11
git checkout v2.8.0
cd ..

Other libraries like JSON can be added as well. Note: it's highly recommended to checkout to the latest stable release of each submodule.

3. Create the DLL project:

• In VS, create a new DLL project, whose name is the same as the desired Python module name.
• Add the path to all submodules into additional include path:
  • Properties --> Configuration Properties --> VC++ Directories --> Include Directories
  • Add $(SolutionDir), $(ProjectDir), $(SolutionDir)..\third_party\pybind11\include\pybind11 and $(SolutionDir)..\third_party\eigen.
• Specify the output file ext to be pyd:
  • Properties --> Configuration Properties --> Advanced --> Target File Extension: .pyd.
• Install the desired Python NuGet Package.
• Add the path to Python headers into additional include path:
  • Properties --> Configuration Properties --> VC++ Directories --> Include Directories
  • Add $(ProjectDir)packages\python.3.8.10\tools\include
• Add path to python3.lib and python38.lib(replace version number based on your installed Python version) to the input of the linker:
  • Properties --> Linker --> Input --> Additional Dependencies
  • add $(ProjectDir)packages\python.3.8.10\tools\libs\python3.lib and $(ProjectDir)packages\python.3.8.10\tools\libs\python38.lib into the list, separated by ;.

A few Windows specific steps:

• If the pyd file is going to be shared, it's better to use the static version of runtime library:
  • Properties --> C/C++ --> Code Generation --> Runtime Library
  • For Release build: Multi-threaded (/MT)
  • For Debug build: Multi-threaded Debug (/MTd)
• If the build time isn't too long, there's no need to use Precompiled Headers:
  • Properties --> C/C++ --> Precompiled Headers --> Precompiled Header: Not Using Precompiled Headers.
• If Windows APIs are called, add WindowsApp.lib into the input of the linker:
  • Properties --> Linker --> Input --> Additional Dependencies: add WindowsApp.lib into the list, separated by ;.

Reuse This Repo

Clone the repo:

git clone https://github.com/zhwa/PyCppDemo.git
cd PyCppDemo
git submodule update --init --recursive

Change the Python NuGet package version: start Python and check the Python version. Right click project --> Manage NuGet Packages... --> Updates --> Version.

Other Misc Notes

• Choose Windows Desktop Dynamic-Link Library (DLL). Avoid Windows Universal DLL (Universal Windows). Otherwise, the C++ functions won't be exported to Python.

• Set Conformance mode --> No; and Enable Run-Time Type Information --> Yes

• If there are compiler complaints about CRT security: In pch.h --> #define _CRT_SECURE_NO_WARNINGS