Call C / C ++ from Python on Mac

This is the first post. I recently requested to touch Python, but it's slow. But when I had to write it in Python, I asked, "Why don't you call me C !?" But it didn't work as I did in the articles written by others. I was wondering if the reference or something was wrong, but I made a note because it moved when I moved it forcibly.

Overview

It seems that you should use the one called ** Boost.Python **. I couldn't browse the library, so I put it all in one directory ** and it worked.

environment

macOS 10.13.6 Python 3.7 BoostPython 1.68.0

Prepare what you need

I have prepared a directory * to execute this program. I think it can be anywhere, but I chose ~ / Python / BoostPythonTest /. Prepare the following items here.

• libboost_python37.dylib
• libpython3.7.dylib --C / C ++ source --Python source

libboost_python37.dylib Install Boost.Python below. [^ 1]

% brew install boost-python3

Once installed, you should have /usr/local/Cellar/boost-python3/1.68.0/lib/libboost_python37.dylib, copy it to the * execute directory *.

libpython3.7.dylib Have Python installed. [^ 1]

% brew install python3

Copy /usr/local/Cellar/python/3.7.2/Frameworks/Python.framework/Versions/3.7/Python to the * execution directory * and rename it to libpython3.7.dylib.

C / C ++ source

I prepared a source called hello.cpp for testing.

hello.cpp

#include <boost/python.hpp>
#include <stdio.h>

char greet(int x){
    printf("printHELLO!!\n");
    return '0' + x + 1;
}

char const* fine(){
    return "How are you?";
}

BOOST_PYTHON_MODULE(hello){
  using namespace boost::python;
    def("greet", greet);
    def("fine", fine);
}

Python source

I prepared a source called test.py for testing.

test.py

import hello
x = hello.greet(2)
print(x)
y = hello.file()
print(y)

compile

You should be able to compile with: Just browse for the files in * the directory you want to run *.

% g++ -fPIC -Wall -O2 -shared -o hello.so hello.cpp libboost_python37.dylib libpython3.7.dylib

hello.so is created in the * execution directory *.

Run

Try to run it.

% python3 test.py
printHELLO!!
3
How are you?

It seems to be done properly.

Summary

It was a bit of a brute force method to put everything in one directory and move it, but it worked for the time being, so let's do it.

I tried to run it on Ubuntu, but I couldn't. I'm using dylib, so it seems to be useless unless it's a Mac.

reference

[1] Wrap c / c ++ so that it can be used in python https://www.quark.kj.yamagata-u.ac.jp/~hiroki/python/?id=19

[2] From boost installation to execution (boost :: python). http://nonbiri-tereka.hatenablog.com/entry/2014/02/01/004547

[^ 1]: If you get a permission error when using brew, dosudo brew ....