Import C++ function into Python program

Question

I'm experimenting with python functions right now. I've found a way to import python functions into c/c++ code, but not the other way around.

I have a c++ program written and it has a certain function in it. I'd like to "import" the compiled c++ program into my python script and call the c++ function.

For simplicity, say the c++ function is as simple as:

int square(x) {   return x*x; } 

and the compiled program is named Cprog.

I'd like my python script to be something like:

import Cprog  print Cprog.square(4) 

Is this possible? I've searched the internet to no avail and I'm hoping one of you gurus might have a clever way of going about this...

Answer 1

Here is a little working completion of the simple example above. Although the thread is old, I think it is helpful to have a simple all-embracing guide for beginners, because I also had some problems before.

function.cpp content (extern "C" used so that ctypes module can handle the function):

extern "C" int square(int x) {   return x*x; } 

wrapper.py content:

import ctypes print(ctypes.windll.library.square(4)) # windows print(ctypes.CDLL('./library.so').square(4)) # linux or when mingw used on windows 

Then compile the function.cpp file (by using mingw for example):

g++ -shared -c -fPIC function.cpp -o function.o 

Then create the shared object library with the following command (note: not everywhere are blanks):

g++ -shared -Wl,-soname,library.so -o library.so function.o 

Then run the wrapper.py an the program should work.