[Pythonmac-SIG] Getting closer on C module extension building.

[Lou Pecora]

Ok, maybe I'm homing in on things and with some help will be able to supply
a little demo for new Python/Mac people on how to do a (very) simple C
module to extend Python.  But I still need some help.  Here's what I have
(a bit long sorry):

----- C Header:  C_test.h ------------------------------------------

/* Header to test of C modules for Python: C_test.c */

/* ==== Includes =====================================*/
#include "Python.h"

/* ==== Prototypes =================================== */
static PyObject *square(PyObject *self, PyObject *args);
void initC_test();

----- C source:  C_test.c ------------------------------------------

/* A file to test imorting C modules to Python.
   The function square just squares the input number and returns result. */

#include "Python.h"
#include "C_test.h"

/* ==== square function ====================== */
static PyObject *square(PyObject *self, PyObject *args)
{
	double x,y;
	if (!PyArg_ParseTuple(args, "d", &x))
		return NULL;
	y=x*x;
	return Py_BuildValue("d", y);
}

/* ==== Set up the methods table ====================== */
static PyMethodDef C_testMethods[] = {
	{"square", square, METH_VARARGS},
	{NULL, NULL} /* Sentinel */
};

/* ==== Initialize the C_test functions ====================== */
void initC_test()  {
	(void) Py_InitModule("C_test", C_testMethods);
}


------ Codewarrior project ----------------------------------

Set to produce a shared library with no main (__start removed from the
linker main:  option -- had some online help with that one).

Library module is named:  C_test.ppc.slb  and compiles with no errors or
warnings.  Shows up nicely with seemingly correct icon.

----- Import attempts in Python IDE ---------------------------

Setting a path to the module's folder and typing

import C_test yields

>>> import C_test
Traceback (innermost last):
  File "<input>", line 1, in ?
ImportError: initC_test: The specified symbol was not found.


OK. initC_test is there.  Removing the module from the folder causes the
error message that it can't find the file so I know Python knows to look
for the shared lib. module.

Anyone know why it can't find the initC_test symbol/function?  Thanks.

More questions to come, I'm sure.




Cheers,

Lou Pecora