Re: [C++-SIG] Python calling C++ issues

Nov. 24, 1999

      Hi Mark,

Thanks a lot for your great help.

Unfortunately, we don't seems to understand what do you mean by "Object". Is
it something we need to define or is it already defined in a h file that we
forgot to include. We use Linux/gcc environment.

Also, in our sample, we did not use virtual function

Below, for all of us we are using the WEB to look at the SIG C++ posting ,
please find the project files.

Thanks,
Ephi.

========================================================================
// c_spam.cpp

#include "spam.h"

extern "C" Spam* new_Spam(int a, int b)
{
 Spam* spam = new Spam(a, b);

 return spam;
}

extern "C" void Spam_Display(Spam* spam)
{
 spam->Display();
}

extern "C" void delete_Spam(Spam* spam)
{
 delete spam;
}

========================================================================
// c_spam.h

#include "spam.h"

extern "C" Spam* new_Spam(int a, int b);
extern "C" void Spam_Display(Spam* spam);
extern "C" void delete_Spam(Spam* spam);

========================================================================
// ext_spam.cpp

// spam extension module.

#include "Python.h"
#include "c_spam.h"

static PyObject*
ext_new_Spam(PyObject* self, PyObject* args)
{
 int a, b;

 if (!PyArg_ParseTuple(args, "ii", &a, &b))
  return NULL;

 Spam* spam = new_Spam(a, b);

 return Py_BuildValue("O", spam);
}

static PyObject*
ext_Spam_Display(PyObject* self, PyObject* args)
{

 Spam* spam;

 if (!PyArg_ParseTuple(args, "O", &spam))
  return NULL;

 Spam_Display(spam);

 return Py_BuildValue("");
}

static PyObject*
ext_delete_Spam(PyObject* self, PyObject* args)
{
 Spam* spam;

 if (!PyArg_ParseTuple(args, "O", &spam))
  return NULL;

 delete_Spam(spam);

 return Py_BuildValue("");
}

// "method table"
static PyMethodDef c_spamMethods[] =
{
 {"new_Spam", ext_new_Spam, 1},
 {"Spam_Display", ext_Spam_Display, 1},
 {"delete_Spam", ext_delete_Spam, 1},

 {NULL,NULL}
};

file://Initialization function that registers new methods with Python
interpreter.
extern "C" void
initc_spam()
{
 PyObject *m;

 m= Py_InitModule("c_spam", c_spamMethods);

}
========================================================================
#makefile

PPFLAGS = -fpic
LFLAGS =
CPP = g++
INCLUDE = /usr/include/python1.5

SOURCES = spam.cpp c_spam.cpp ext_spam.cpp

OBJECTS = spam.o c_spam.o ext_spam.o

TARGET = c_spammodule.so

####### Implicit rules

.SUFFIXES:  .cpp

.cpp.o:
 $(CPP) $(CPPFLAGS) -c -I$(INCLUDE) $<

####### Build rules

all: $(TARGET)

$(TARGET): $(OBJECTS)
 $(CPP) -shared $(OBJECTS) -o $(TARGET)

showfiles:
 @echo $(SOURCES) makefile

clean:
 rm -f *.o
 rm -f $(TARGET)
 rm -f tags
 rm -f core
========================================================================
run:

#!/usr/bin/python

import c_spam

myspam=c_spam.new_Spam(8, 5)
c_spam.Spam_Display(myspam)
c_spam.delete_Spam(myspam)

print "python end"

========================================================================
// spam.cpp

#include <iostream>
#include "spam.h"

Spam::Spam(int a, int b) : m_a(a), m_b(b)
{ 
 cout << endl;
 cout << "In Spam::Spam,    ";
 cout << "m_a = " << m_a << "   m_b = " << m_b << endl;
}

void Spam::Display()
{
 cout << "In Spam::Display, ";
 cout << "m_a = " << m_a << "   m_b = " << m_b << endl;
}

Spam::~Spam()
{
 cout << "In Spam::~Spam,   ";
 cout << "m_a = " << m_a << "   m_b = " << m_b << endl;
}
========================================================================
// spam.h

class Spam 
{
public:
 Spam(int a, int b); 
 void Display();
 ~Spam();
private:
 int m_a;
 int m_b;
};
========================================================================

Re: [C++-SIG] Python calling C++ issues

Ephi Dror