Swig, Python, and C++

[Mich Peffe]

Greetings All,

I'm using SWIG for the first time and am running into some problems.  I've tried researching at swig.org and python.org, but unfortunately, most of the examples use programs I don't have, such as Solaris, Unix, and Irix.  I wish to make my C++ classes and functions accessible from Python, and create the glue code necessary to interface with my compiler.  I'm using Python 2.4, MS Visual Studio 2005, and Windows XP command prompt.

C++ Code:
/* FuncTest.h */

#include <time.h>

int fact(int n)
{
    if(n <=1) return 1;
    else return n*fact(n-1);
}

char *get_time()
{
    time_t ltime;
    time(&ltime);
    return ctime(&ltime);
}

Interface File:
/* example.i */
%module example
%{
#include "FuncTest.h"
%}

%include "FuncTest.h"

Command Prompt Input:
c:\Utilities\Swig\swig -python -c++ example.i

example.py and example_wrap.cxx are then created. 

This is where I hit the wall.  example_wrap.cxx can't be included in my project because it creates 2 linker errors:
 
error LNK2005: _SWIG_init already defined in Main.obj    PENT_wrap.obj
fatal error LNK1169: one or more multiply defined symbols found    C:\My Work\PEntityTest\Release\PEntityTest.exe    1

These errors are because of this chunk of code created by SWIG:
#ifdef __cplusplus
extern "C"
#endif
SWIGEXPORT void SWIG_init(void) {
  PyObject *m, *d;
 
  /* Fix SwigMethods to carry the callback ptrs when needed */
  SWIG_Python_FixMethods(SwigMethods, swig_const_table, swig_types, swig_type_initial);
 
  m = Py_InitModule((char *) SWIG_name, SwigMethods);
  d = PyModule_GetDict(m);
 
  SWIG_InitializeModule(0);
  SWIG_InstallConstants(d,swig_const_table);
 
 
}

I can't import the example.py module because the generated script tries to import _example.

I assume this file is created in another step that I haven't figured out how to do yet. The SWIG tutorial instructs the following:

unix % swig -python example.i
 unix % gcc -c example.c example_wrap.c \
        -I/usr/local/include/python2.1
 unix % ld -shared example.o example_wrap.o -o _example.so 

I believe this is what I need to do, but using XP command prompt.

Any feedback on any one little chunk of this huge post would be helpful.

Much thanks.

-Mich

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