I'm not 100% sure, but try the following:

static unsigned int eigenvect_calc(double *min_eps) { return 5; }

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

Try adding a 3rd arg - PyObject *kw - although I was under the impression this should not matter, it might. Indeed, I hope it does, as I can't spot any other issue.

Mark

Hi, as mentioned before, the pointers the issue here,

Some other things you might want to consider. there more of a style thing ;)

static PyObject *cmat_eigv(PyObject *self, PyObject *value) { double min_eps = PyFloat_AsDouble(value); if (min_eps==-1 && PyErr_Occurred()) return NULL; return PyInt_FromLong((long)eigenvect_calc(min_eps)); } static PyMethodDef cmat_methods[]= { { "eigenvect", cmat_eigv, METH_O, "Comment"},{NULL, NULL, 0, NULL} };

notice that Iv replaced METH_VARARGS with METH_O, this means the function only accepts 1 arg and you can use that as a float without using PyArg_ParseTuple - This should be a bit faster too.

PyFloat_AsDouble will convert from ints or other non float types that support the PyNumber protocol.

I can see why this isnt used for an example because its much less generic.

Ali Alhakim wrote:

Hello!

I'm quite new to Python and definitely a beginner in implementing Python extensions in C/C++. I've followed the structure given in the formal Python documentation to write the following code block:

//cmatmod.c

#include

static unsigned int eigenvect_calc(double *min_eps) { return 5; }

static PyObject *cmat_eigv(PyObject *self, PyObject *args) { double *min_eps; unsigned int m; if(!PyArg_ParseTuple(args, "d", &min_eps)) return NULL; m=eigenvect_calc(min_eps); return Py_BuildValue("I", m); } static PyMethodDef cmat_methods[]= { { "eigenvect", cmat_eigv, METH_VARARGS, "Comment"},{NULL, NULL, 0, NULL} };

void initcmat(void) { (void) Py_InitModule("cmat", cmat_methods); }

===========

I have succeeded to build and install this extension using disutils package in the setup.py file below:

from distutils.core import setup from distutils.extension import Extension setup(name='eigenvect', version='1.0', ext_modules=[Extension('cmat', ['cmatmod.c'])], )

========== But when I try to call eigenvect(3.0) from Python I would receive a core dump:

6 [main] python 2336 _cygtls::handle_exceptions: Error while dumping state (probably corrupted stack) Segmentation fault (core dumped)

========== My question is what is wrong with the extension code above? Is it something with reference counting? I don't know which method is suitable for debugging extension codes. I've tried gdb but I didn't understand the debug information:

(gdb) >>> eigenvect(4.0)

Program received signal SIGSEGV, Segmentation fault. ---Type to continue, or q to quit--- 0x6abb248e in libpython2!PyEval_EvalFrameEx () from /usr/bin/libpython2.5dll (gdb)

========== /best regards

Gå in och titta på nätets roligaste filmer just nu eller ladda upp ditt eget bidrag på Spray Crazy. http://crazy.spray.se/

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