embedding python in c++

Question

I created a VCL Application in c++, borland. In my project there is a file where I have implemented embedded python in the methods defined in the same(my application contains a button which calls the method in which embedded python is implemented). when I compile, my build is successful. but when I run my application, and click on the button it shows the run time error : "Access violation at address 1E091375 in module 'PYTHON25.DLL'. Read of address 00000004" . please help. I have never used Python before. my program:

#pragma hdrstop

#include <fstream>
#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>


#include "Python.h"

#include "Unit1.h"
#include "Unit2.h"
#pragma link "python25_bcpp.lib"

//---------------------------------------------------------------------------

#pragma package(smart_init)

bool callHelloWorld(int intVal)
{
    char fName[] = "Hello"; //file name
    char cFunc[] = "hello"; //method name

    char *pfName, *pcFunc;

    PyObject *pName, *pModule, *pDict, *pFunc ;

    pfName = fName;
    pcFunc = cFunc;

    Py_Initialize();

    pName = PyString_FromString(pfName);

    pModule = PyImport_Import(pName);

    pDict = PyModule_GetDict(pModule);

    pFunc = PyDict_GetItemString(pDict, pcFunc);

    if (PyCallable_Check(pFunc))
    {
        PyObject_CallObject(pFunc, NULL);
    } else
    {
        PyErr_Print();
    }


    // Py_DECREF(pModule);
    // Py_DECREF(pName);

    Py_Finalize();

    return 0;
}

I seem to remember that Borland C++ uses a different calling convention (fastcall?). Is your python.dll compiled using the same compiler? — cdarke
– cdarke, Commented Oct 9, 2011 at 18:43
the python25.dll was in C:\Windows\SysWOW64. I didnt compile it. — Amit Mandal
– Amit Mandal, Commented Oct 9, 2011 at 18:55
I dont know if this would help or not, but I think you are missing some of the python files. I remember getting the same error when trying to compile my program on a different machine. But in my case I was using an MFC program and I was accessing my MFC DLL using the python script. Probably try reinstalling python. — Neophile
– Neophile, Commented Oct 9, 2011 at 19:18
I have placed all the files like .h ,lib and .dll in the source folder. I think the issue is with loading the module Hello.py. Can you please suggest how should i load the module successfully. — Amit Mandal
– Amit Mandal, Commented Oct 9, 2011 at 19:28
It won't be calling convention since python.h will specify cdecl. To help us can you tell us which line fails. — David Heffernan
– David Heffernan, Commented Oct 9, 2011 at 19:59

Karoly Horvath · Accepted Answer · 2011-10-09 19:50:34Z

1

Check the return values of PyImport_Import (is the module in the search path?) and PyDict_GetItemString.

If that doesn't help put some trace messages in your app to see where it crashes.

answered Oct 9, 2011 at 19:50

Karoly Horvath

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Comments

Thiem Nguyen · Accepted Answer · 2012-06-25 16:00:54Z

1

This works for me:

Just delete Py_Finalize()

I read in another site that Py_Finalize has some problems in specific cases such as threading.

edited Jun 25, 2012 at 16:00

Thiem Nguyen

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answered Jun 25, 2012 at 14:46

Rodrigo

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1 Comment

Cem Polat Over a year ago

Same issue and same solution after all those years. Use Py_FinalizeEx for Python 3.

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