Python extension, where am I going wrong

Discussion in 'Python' started by John Vines (CISD/HPCD), Sep 10, 2008.

  1. All,
    I am trying to create an extension module and keep getting an error,
    "/usr/local/lib/python2.5/site-packages/ undefined symbol:

    thanks in advance,

    *Here is my source code and information:

    */* mytest.c */
    #include <Python.h>
    #include <unistd.h>
    #include <stdlib.h>
    #include <sys/types.h>

    static PyObject *ErrorObject;

    static char isEven__doc__[] = "Method to determine if number is odd or

    static PyObject *isEven(PyObject *self, PyObject *args){
    int inputValue;
    int returnValue;

    if (!PyArg_ParseTuple(args, "i", &inputValue)){
    PyErr_SetString(PyExc_ValueError, "Argument parsing Error");
    return NULL;

    if ( 0 == inputValue%2 ){
    returnValue = 1;
    } else {
    returnValue = 0;
    return Py_BuildValue("i", returnValue);

    static char getFactorial__doc__[] = "This module takes a number as a
    parameter \
    and returns the factorial of that number\n";

    static PyObject *getFactorial(PyObject *self, PyObject *args){
    int inputValue;
    int resultValue;

    if (!PyArg_ParseTuple(args, "i", &inputValue)){
    PyErr_SetString(PyExc_ValueError, "Argument parsing error");
    return NULL;

    resultValue = factorialHelper(inputValue);
    return PyInt_FromLong(resultValue);

    int factorialHelper(int factor){
    if (factor <= 0){
    return 0;
    if (factor == 1){
    return 1;
    return factor*factorialHelper(factor-1);

    static struct PyMethodDef mytest_methods[] = {
    {"isEven", isEven, METH_VARARGS, "Determine odd/even of a number"},
    {"getFactorial", getFactorial, METH_VARARGS, "Calc the factorial
    value of a number"},
    {NULL, NULL, 0, NULL}

    void initmytest(){
    PyObject *m, *d;

    m = PyInitModule("mytest", mytest_methods);
    d = PyModule_GetDict(m);

    ErrorObject = PyBuildValue("s", "mytest module error");
    PyDict_SetItemString(d, "Error", ErrorObject);

    if (PyErr_Occurred())
    Py_FatalError("Can't initialize module mytest!");

    *My code:*
    #!/usr/bin/env python
    from distutils.core import setup, Extension

    setup(name="mytest", version="1.0",
    ext_modules=[Extension("mytest", ["mytest.c"])])
    John Vines (CISD/HPCD), Sep 10, 2008
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.