[Pythonmac-SIG] undefined symbols when making python wrapped c libs for itk

[Bob Ippolito]

The correct way to link Python extensions is to use distutils, end of
story. The compiler/linker flags are different for every platform and
sometimes differ based upon the way it's built. Specifically in this
case all that should be necessary is -undefined dynamic_lookup --
however, the only good fix is to use distutils.

-bob

On 12/14/06, Dan White <dan at chalkie.org.uk> wrote:
> Hi,
>
> Actually i see the same error message using python2.5 when building
> ITK python wrapping.
>
> I was wondering what i am doing wrong that  ld is not seeing pytohn
> properly to find those symbols?
>
> Any one know what is going wrong to give error message like
>
> >> /usr/bin/ld: Undefined symbols:
> >> _main
> >> _PyArg_ParseTuple
> >> _PyInt_FromLong
> >> _PyString_FromString
> >> _PyTuple_New
> >> _PyTuple_SetItem
> >> _Py_InitModule4
> >> collect2: ld returned 1 exit status
>
> which lib or headers or something is ld not seeing?
>
> cheers
>
> Dan
>
>
> On 14 Dec 2006, at 13:00, pythonmac-sig-request at python.org wrote:
>
> > From: "Bob Ippolito" <bob at redivi.com>
> > Date: 14 December 2006 12:28:29 GMT+02:00
> > To: "Gen Kazama" <generalkernel at gmail.com>
> > Cc: pythonmac-sig at python.org
> > Subject: Re: [Pythonmac-SIG] CPython on Mac OSX
> >
> >
> > On 12/13/06, Gen Kazama <generalkernel at gmail.com> wrote:
> >> Hi I'm running python 2.3 on 10.4.  i made an application using a
> >> C backend
> >> and a python frontend.
> >>
> >> This is a school project and although it works perfectly on the
> >> school
> >> computers, i have trouble compiling the C code correctly on the
> >> mac to make
> >> it into a python module (maybe this is because the school
> >> computers used
> >> python 2.4-ie, an updated version of Python.h).
> >>
> >> Anyway here is how I compile it at school:
> >>
> >>         gcc -I /usr/include/python2.4 -c mandel.c
> >>         gcc -shared mandel.o -o mandel.so
> >>
> >> which works with no flaws.  then , I try compiling it on my mac:
> >>
> >>         gcc -I /usr/include/python2.3 -c mandel.c
> >>         gcc mandel.o -o mandel.so
> >>
> >> (note: -shared wasn't found on my mac for some reason). I get the
> >> following
> >> errors:
> >>
> >> /usr/bin/ld: Undefined symbols:
> >> _main
> >> _PyArg_ParseTuple
> >> _PyInt_FromLong
> >> _PyString_FromString
> >> _PyTuple_New
> >> _PyTuple_SetItem
> >> _Py_InitModule4
> >> collect2: ld returned 1 exit status
> >>
> >>
> >> If anyone could tell me how to compile this C code into a python
> >> module on
> >> my mac, i would greatly appreciate it.  thanks!
> >
> > The best way is to use distutils (or setuptools). Create a setup.py
> > that compiles it for you. This works on every platform, even windows.
> >
> > -bob
>
> Dr. Daniel James White BSc. (Hons.) PhD
> Bioimaging Coordinator
> Nanoscience Centre and Department of Biological and Environmental
> Sciences
> Division of Molecular Recognition
> Ambiotica C242
> PO Box 35
> University of Jyväskylä
> Jyväskylä
> FIN 40014
> Finland
>
> +358 14 260 4183 (work)
> +358 468102840 (mobile)
> http://www.bioimagexd.org
> http://www.chalkie.org.uk
> dan at chalkie.org.uk
> white at cc.jyu.fi
>
>
>
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