[Cython] How to produce Python 3.0.1 compatible DLLs?

[Dag Sverre Seljebotn]

Juha Salo wrote:
> Hi, 
> 
> I've been struggling with this for a day now. I'm trying to get the 
> Primes example from the Cython tutorial to work with Python 3.0.1 on 
> Windows Vista. So far I've managed to produce a primes.pyd file by 
> executing the setup.py file with Python 2.6. The primes module works 
> when I import it in Python 2.6 but importing the module in Python 3.0.1 
> gives me the following:
> 
> "ImportError: Module use of python26.dll conflicts with this version of 
> Python."
> 
> I haven't found instructions for using cython with Python 3. The only 
> things I've found are the brief mention of Python 3 support in the 
> cython docs and a forum post explaining that cython modules should be 
> build with Python 3 headers before they can be used with Python 3 but I 
> have no idea how to do it. Could anyone offer me some help with this? If 
> there's a tutorial somewhere on the net, I'd love to hear about it.

You need to execute setup.py using Python 3.0 to build for Python 3.

Details: The C file generated by Cython is the same for all Python 
versions, however it must be compiled with a different include path for 
the Python headers depending on the Python version.

Executing setup.py with the right Python version takes care of this 
automatically. You can see this by

Py3> from distutils import sysconfig
Py3> sysconfig.get_python_inc()
'/home/dagss/opt/python3.0/include/python3.0'

which should be passed as an include path to the C compiler.

Feel free to add this to the wiki in a place you would have found it if 
you get it to work.

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Dag Sverre