[Distutils] Solaris and distutils: Need to pass LIBDIR explicitly with -L when building extensions?

[Floris Bruynooghe]

On Fri, Jan 30, 2009 at 05:45:26PM -0600, Dave Peterson wrote:
> Floris Bruynooghe wrote:
>> On Mon, Jan 26, 2009 at 06:48:06PM -0600, Dave Peterson wrote:
>>   
>>> I am trying to build a number of projects that use Python extensions 
>>> on  Solaris 10 and I've discovered that nothing with extensions will 
>>> link  unless I explicitly pass in a '-L/path/to/python/lib/dir' 
>>> because  libpython2.5.so is not otherwise found when the 
>>> '-lpython2.5' argument  is specified during linking.
>>>     
>> [...]
>>   
>>> If that all seems correct, then it appears the issue is the   
>>> finalize_options() source in lib/distutils/commands/build_ext.py.  
>>> There  are a number of "if" blocks that explicitly append the value 
>>> of  distutils.sysconfig.get_config_vars('LIBDIR') to the list of   
>>> library_dirs used to link built extensions with.  However, there 
>>> doesn't  seem to be one of these for Solaris / sunos.
>>>     
>>
>> Could you point to one of the projects you're having trouble with?  I
>> haven't had any such problems with Python 2.5 on Solaris 10, distutils
>> always finds the right things when I'm building extension modules.
>>   
>
> Pretty much everything I've tried that uses an extension has this  
> problem.  Cython, Numpy, Traits, etc.  As Robert Kern pointed out, I'm  
> using a custom built Python (Python 2.5.4) built and installed into a  
> custom location via '--prefix'.   What Python are you using?

Ah, I get it now.  I did cut out the important part: you build with
--enable-shared.  I'm also using a custom build Python with --prefix
but don't use --enable-shared so don't get this problem.

> I'm leaning more and more toward this is actually a bug  
> with the distutils source on Solaris.

Yes, I agree now that it is a bug in distutils and I agree with your
fix.  The if statement should check both that it is SunOS and that it
is using a shared python, just like the linux one.  If fact the linux
one could just be modified:

if (sys.paltform.startswith('linux') \
    or sys.platform.startswith('gnu') \
    or sys.platform.startswith('sunos')) \
        and sysconfig.get_config_var('Py_ENABLE_SHARED'):
    ...

I'll leave the honours of reporting the bug to you if you agree with
this.

Lastly out of curiosity: why --enable-shared?  Do you embed python?
Or are there other reasons to use it?

Regards
Floris

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