Run Python in C ++ on Visual Studio 2017

background

At work (), I want to run Python in C ++, and now I have to. At that time, it took a lot of time to build the environment, so I would like to summarize it once. Install some. It also takes time.

Development environment

·laptop ・ OS: window 10 64 bit ・ CPU: Heppoko ・ GPU: None ・ Visual Studio 2017 ・ C ++ -Python 3.7.4

Installation contents

・ Visual Studio 2017 -Python 3.7.4 ・ Boost 1.70.0

Installation: Visual Studio 2017

Go to the URL below and download "** Download Community 2017 **". This can be used free of charge for individuals. We also recommend that you create a Microsoft account. It is said that if you use it for about a month, you will not be able to use it unless you create an account and log in (fear).

`URL`


https://docs.microsoft.com/ja-jp/visualstudio/releasenotes/vs2017-relnotes

Then install it. Check "** Desktop development with C ++ " on the left side and " WINDOWS 10 SDK ** on the right side" respectively. ** Python can't be included here **. This time I will put in genuine Python. You can add Python (or anaconda) by Visual studio 2017, I'm afraid to make Python dependent on Visual studio 2017 personally, so Build the environment so that they are independent of each other.

The installation will start as shown below.

Installation: Python 3.7.4

You can check how to install Python on many sites, but I will post it for confirmation.

`URL`


https://www.python.org/downloads/release/python-374/

Scroll down the URL and you will find Files. Since the OS is windosn 64bit, download ** windos x86-64 executable installer **.

Check Add Python 3.7 to PATH and pass the environment variable path in your PC.

Installation: boost 1.70.0

Download from the following URL.

`URL`


https://www.boost.org/users/history/version_1_70_0.html

boost also has a library element that connects C ++ and Python. There is also the latest version, but I have confirmed that 1.70.0 can be used before, so I specified this this time.

Download it, unzip it, and place it directly under your C drive. ** Please note that setting boost takes a considerable amount of time. ** ** It takes a terrifying amount of time. So wait patiently when working with files. I'm taking 30 minutes to unzip the zip file. Note the location of the directory.

Then install boost at the command prompt (cmd). ○○ is the user name.

`cmd`


C:\Users\○○ > cd C:\boost_1_70_0
C:\boost_1_70_0>bootstrap.bat

Execution result of bootstrap.bat.

`cmd`


Building Boost.Build engine

Generating Boost.Build configuration in project-config.jam for msvc...

Bootstrapping is done. To build, run:

    .\b2

To adjust configuration, edit 'project-config.jam'.
Further information:

    - Command line help:
    .\b2 --help

    - Getting started guide:
    http://boost.org/more/getting_started/windows.html

    - Boost.Build documentation:
    http://www.boost.org/build/

I installed Visual Studio 2017 in 1. Pay attention to each version when installing boost. · Visual Studio 2017 is mscv-14.1 -64bit x64 Also, install boost by typing the following without moving the directory.

`cmd`


b2.exe toolset=msvc-14.1 link=static runtime-link=static,shared --build-dir=build/x64 address-model=64 -j5 install --includedir=C:\boost_1_70_0\include --libdir=C:\boost_1_70_0\stage\lib\x64

Please note that it is not mscv-14.1 in 2019 and 2015 other than Visual Studio 2017. Visual Studio 2019 version is mscv-14.2 (confirmed) Visual Studio 2015 version is mscv-14.0 (unconfirmed)

Execution of sample program

I'm ready. It may have taken some time to boost, but let's keep going (sweat).

Create a new project

Launch Visual Studio 2017 and launch a new project. Select a console app in C ++. The project name this time is test_Cplus2_Python.

Set project properties

Right-click on the project and select Properties. There are four setting items.

Change the solution configuration and solution platform. Set on both the property page and the main screen. It's easy to forget to change this setting.
Include boost and Python.
Set to multithreading.
Link boost and Python .lib files.

`Property page settings`


1.Solution configuration and solution platform
Changed from Debug to Release
x86 → x64

2. C++→ General → Additional include
C:\boost_1_70_0
C:\Users\○○\AppData\Local\Programs\Python\Python37\include

3. C++→ Code generation → With runtime library
Multithread(/Change to MT)

4.Linker → General → Additional library directory
C:\boost_1_70_0\stage\lib\x64
C:\Users\○○\AppData\Local\Programs\Python\Python37\libs

The setting items are surrounded by a red outer frame. ○○ is the user name.

Run only once

Once you have set the project properties, run the program once. By executing it, you can confirm that the project works and create an .exe file. It's okay if Hello world! Appears.

C ++ and Python sample code

Since C ++ calls Python and Python files (.py), you have to write code for each. Write C ++ on Visual Studio, create new text for Python, and write the test code below.

For C ++, define a python namespace and function

`test_Cplus2_with_Python.cpp`


#define BOOST_PYTHON_STATIC_LIB

#include <iostream>
#include <boost/python.hpp>

int main()
{
	//Namespace
	namespace py = boost::python;
	//Initialization
	Py_Initialize();
	//output
	std::cout << "Hello World! from C++ \n";

	//Python files(test_py.py)Import
	py::object module_ns = py::import("test_py").attr("__dict__");
	//Define functions in the imported file
	py::object get_and_return = module_ns["hello_from_python"];
	//Execute the imported function
	auto return_nd_array = get_and_return();
}

Make the Python file to be called a simple process as follows.

`test_py.py`


def hello_from_python():
        print("Hello World! from Python")

Folder structure

The C ++ code I just created test_Cplus2_with_Python → Write to test_Cplus2_with_Python.cpp, The Python code places x64 → Release → test_py.py.

`Folder structure`


test_Cplus2_with_Python(Self-made folder)
　├── test_Cplus2_with_Python
　│　　├── test_Cplus2_with_Python.cpp 〇
　│　　├── test_Cplus2_with_Python.vcxproj
　│　　├── test_Cplus2_with_Python.vcxproj.filters
　│　　├── test_Cplus2_with_Python.vcxproj.user
　│　　└── x64
　│　　
　├── x64 
　│　　└── Release
　│　　     ├── test_Cplus2_with_Python.exe
　│　　     ├── test_Cplus2_with_Python.iobj
　│　　     ├── test_Cplus2_with_Python.ipdb
　│　　     ├── test_Cplus2_with_Python.pdb
　│　　     └── test_py.py 〇
　│　
　└── test_Cplus2_with_Python.sln

Execution result

If you can output the C ++ and Python strings respectively, you are successful.

If you can't, -The settings on the project page are incorrect. -The code in the Python file is incorrect -The location of the Python file is incorrect -The boost installation is incorrect And so on.

Reflection

I don't think it's so common to call Python in C ++. It is useful when using Python's deep learning tools in C ++. I sincerely hope that it will be useful to various people, including juniors. If I can afford it, I would like to post an implementation of the object detection method (YOLOv3) using Python's deep learning in C ++.

Github Please for your reference.

`URL`


git clone https://github.com/yusa0827/200121_Cplus2_with_Python

Cloning and running doesn't work. Please reset your own environment path in visual studio.