embedding python in c++ , example

Question

I would love to embed this python program on a c++ one , but I'm kinda struggling there , I never studied python , and even after reading the explanation in others websites about the method I couldn't really apply it , because I don't know what are those python members ,I want to run this program under c++, this code is a good one , but couldn't find it in c++ version , this is why I decided to use the embedded option .

here is the python program

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Le Raspbery Pi envoie des messages à l'Arduino
import serial # bibliothèque permettant la communication série
import time # pour le délai d'attente entre les messages
ser = serial.Serial('/dev/ttyACM0', 9600)
compteur = 0
while True: # boucle répétée jusqu'à l'interruption du programme
 if compteur < 6:
 compteur = compteur + 1
 else:
 compteur = 0
 ser.write(str(compteur))
 time.sleep(1) # on attend pendant 2 secondes

and here is the embedded program that I tried , but I'm pretty sure that its wrong , because there is no call of python object

#include <iostream>
#include <Python.h>
int main(int argc, char **argv) {
 Py_Initialize();
 return 0;
}

Can anybody help me to do this !? thanks in advance .

• MadHer: @PaulWürtz thanks for your proposition , yes I did before this and I did choose this solution because its the more oprtimal for me , and for the example on the website its written on c , I know that we can execute it even in c++ , but in my case , this is not the good one .
• MadHer: I'm trying right now to right the same code , using another library in c++ , for exactly those serial communication , will try to post it after , but , I would really love to see the embedded version of the python code , exactly because its a simple one

Answer 1

For simple application as this, I wouldn't link the python headers to your programm, but as a more easy solution I would trigger the system() command of C++ and process the output.

Here a example from this question:

#include <cstdio>
#include <iostream>
#include <memory>
#include <stdexcept>
#include <string>
#include <array>
std::string exec() {
 std::array<char, 128> buffer;
 std::string result;
 const char* cmd = "./python script.py";
 std::shared_ptr<FILE> pipe(popen(cmd, "r"), pclose);
 if (!pipe) throw std::runtime_error("popen() failed!");
 while (!feof(pipe.get())) {
 if (fgets(buffer.data(), 128, pipe.get()) != nullptr)
 result += buffer.data();
 }
 return result;
}

You would then have to change the infinite loop in your python code, so that the python programm terminates and the rest of your C++ code executes, then you could probe the arduino with your python script from you C++ program.

• MadHer: actually this code will be executed under a QT gui , I m not sure if this solution is the right one for me , I just want to embedd this code hh , if you can help there .
• Paul Würtz: Using Pythons Qt modules seems off, since you are more familiar with C++? Here a post that migth help. doc.qt.io/archives/qq/qq23-pythonqt.html But in general triggering system() in a Qt program does not seem all to wrong for me ;)
• MadHer: I didnt get what you want to say for real , but I will explain , Im using QT with c++, and Ill be just adding the python path in my makefile .I see , hh but even a simple embedded programm c++ will work , because I will just execute it as a slot for a specific button
• MadHer: ur solution worked , thank you so much , hh but Ill still waiting for somebody else maybe to give me this embedded version .