[Python.NET] Use of c++ dll in python

Mark McMahon mark.mcmahon at eur.autodesk.com
Tue Apr 4 13:55:35 CEST 2006

Hi Lalit,

import ctypes

(or maybe windll instead of cdll below)

Simple, no? :-)

For anything more complex - please look at the ctypes help. 
Ctypes helps you a lot - but there is no substitute for reading the help or googling around the 'net for some examples.


-----Original Message-----
From: Lalit DIGARI [mailto:lalit.digari at st.com] 
Sent: Tuesday, April 04, 2006 12:37 AM
To: Mark McMahon
Cc: pythondotnet at python.org
Subject: RE: [Python.NET] Use of c++ dll in python

Thanks mark,
How could I use dll's exposed function with in python script?

-----Original Message-----
From: Mark McMahon [mailto:mark.mcmahon at eur.autodesk.com] 
Sent: Monday, April 03, 2006 5:41 PM
To: Lalit DIGARI; pythondotnet at python.org
Subject: RE: [Python.NET] Use of c++ dll in python

Hi Lalit,

This is not really the group to ask this question - as it doesn't have
anything to do with python.NET.

But other then that I can answer your question I think :-)

You say a "C++ DLL". First thing is you need to make sure that your
functions are correctly exported in an 'unmangled' form. 

What I do for this is the following:

// create a macro DLLEXPORT for those methods you want to export
#define  DLLEXPORT   extern "C" __declspec(dllexport)

// the following may be optional - but can make things easier
#define  VB 	__stdcall

// add the macro to your function prototypes
DLLEXPORT int VB InitDialogFromFile   (char const *const fileName);

// in the CPP file define your function as you would normally do int VB
InitDialogFromFile(char const * const fileName) {

You may also need to create a .def file

; Declares the module parameters for the DLL.
DESCRIPTION  'Description of your DLL'
	// the following line can be used to rename exports
	//InitDialogFromFile_renamed = InitDialogFromFile

Once you add that to the project - it will make sure that no mangling
happens (sometimes even after doing extern "C" you still get a leading


-----Original Message-----
From: pythondotnet-bounces at python.org
[mailto:pythondotnet-bounces at python.org] On Behalf Of Lalit DIGARI
Sent: Monday, April 03, 2006 7:22 AM
To: pythondotnet at python.org
Subject: [Python.NET] Use of c++ dll in python

Hello All ,
I have devloped a c++ dll named mydll in c++ how can I access it with in
python script using ctype... Regard's Lalit

Python.NET mailing list - PythonDotNet at python.org

More information about the PythonDotNet mailing list