Compiling extension module (linker error)

[Paul Volkov]

I am trying to compile an extension module with C++ Builder 6 for Python 3.3.
I converted python33.lib using coff2omf.exe and added this library
into my project.
I wonder why I get this error message while building:

[Linker Error] Unresolved external '_PyModule_Create2TraceRefs'
referenced from 'D:\WORK\FROMAGE\OUT\ROSE_UNIT.OBJ'

My source file:

//---------------------------------------------------------------------------

#include <Python.h>
#include <windows.h>
#pragma argsused

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fwdreason, LPVOID lpvReserved)
{
return 1;
}

static PyObject* __declspec(dllexport) testik(PyObject* self, PyObject* args)
{
return NULL;
}

static PyMethodDef FundRoseMethods[] = {
{"testik", testik, METH_VARARGS, "perform a test"},
{NULL, NULL, 0, NULL}
};

static struct PyModuleDef FundRoseModule = {
PyModuleDef_HEAD_INIT,
"FundRose",
NULL,
-1,
FundRoseMethods
};

PyMODINIT_FUNC
PyInit_FundRose(void)
{
return PyModule_Create(&FundRoseModule);
}

//---------------------------------------------------------------------------

[MRAB]

On 2012-10-22 11:55, Paul Volkov wrote:
> I am trying to compile an extension module with C++ Builder 6 for Python 3.3.
> I converted python33.lib using coff2omf.exe and added this library
> into my project.
> I wonder why I get this error message while building:
>
> [Linker Error] Unresolved external '_PyModule_Create2TraceRefs'
> referenced from 'D:\WORK\FROMAGE\OUT\ROSE_UNIT.OBJ'
>
> My source file:
>
> //---------------------------------------------------------------------------
>
> #include <Python.h>
> #include <windows.h>
> #pragma argsused
>

It's a Python module with its own initialiser, so you don't need this:

> BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fwdreason, LPVOID lpvReserved)
> {
> return 1;
> }
>

You don't need to export this function because it's listed in the
module's function table:

> static PyObject* __declspec(dllexport) testik(PyObject* self, PyObject* args)
> {

Returning NULL says that an exception was raised. You should set the
exception.

> return NULL;
> }
>
> static PyMethodDef FundRoseMethods[] = {
> {"testik", testik, METH_VARARGS, "perform a test"},
> {NULL, NULL, 0, NULL}
> };
>
> static struct PyModuleDef FundRoseModule = {
> PyModuleDef_HEAD_INIT,
> "FundRose",
> NULL,
> -1,
> FundRoseMethods
> };
>
> PyMODINIT_FUNC
> PyInit_FundRose(void)
> {
> return PyModule_Create(&FundRoseModule);
> }
>
> //---------------------------------------------------------------------------
>

By the way, the recommendation is for module names to be lowercase with
underscores, so "fund_rose" instead of "FundRose".

Try this code:

#include <Python.h>
#include <windows.h>
#pragma argsused

static PyObject* testik(PyObject* self, PyObject* args)
{
PyErr_SetString(PyExc_RuntimeError, "testik exception");

[Paul Volkov]

2012/10/22 MRAB <pyt...@mrabarnett.plus.com>:

> By the way, the recommendation is for module names to be lowercase with
> underscores, so "fund_rose" instead of "FundRose".
>
> Try this code:
>

I tried as you suggested, but the linker error (unresolved external)
is still there.
I'm sure python33.lib is properly added because if I remove it, there
are 3 errors, not 1.
By the way, what is the difference between python3.lib and python33.lib?

[MRAB]

On 2012-10-23 08:00, Paul Volkov wrote:
> 2012/10/22 MRAB <pyt...@mrabarnett.plus.com>:
>> By the way, the recommendation is for module names to be lowercase with
>> underscores, so "fund_rose" instead of "FundRose".
>>
>> Try this code:
>>
>
> I tried as you suggested, but the linker error (unresolved external)
> is still there.

I found a reference to PyModule_Create2TraceRefs in include\modsupport.h.

> I'm sure python33.lib is properly added because if I remove it, there
> are 3 errors, not 1.
> By the way, what is the difference between python3.lib and python33.lib?
>

I don't know.