[f2py] Re: unloading/reloading compiled modules

I tried sending this before I was a subscriber and I'm still waiting
for approval. So apologies if its out of line to be sending again, but
I wanted to get this out there in case anyone had any ideas.

There was a thread on the numpy-discussion list about this, but its really old,
http://www.mail-archive.com/numpy-discussion-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org/msg02661.html

Basically, I want to be able to reload a recompiled Fortran module
without restarting python. This is more or less essential for using
python as a development interface.

I understand that what really needs to happen is for the old version
of the module to first get UNloaded. To this end, I put together the
following script based on what I found at
http://stackoverflow.com/questions/359498/how-can-i-unload-a-dll-using-ctypes-in-python

-------------------------------------
#!/usr/bin/env python
import os
import ctypes
import numpy.f2py

def isloaded(lib):
   libp = os.path.abspath(lib)
   fd=open('/proc/%d/maps'%os.getpid())
   ret=fd.read().find(libp)
   fd.close()
   return (ret != -1)

def dlclose(handle):
   libdl = ctypes.CDLL("libdl.so")
   libdl.dlclose(handle)

def unload(fname):
   mydll = ctypes.CDLL(fname)
   handle = mydll._handle
   del mydll
   while isloaded(fname):
       dlclose(handle)

import yo

yo.yo()

unload('./yo.so')

print 'isloaded(\'./yo.so\') =', isloaded('./yo.so')

import yo

print 'good to here!'

yo.yo()

print 'you\'ll never see this'
----------------------------------------------------------

Where "yo.so" is compiled from yo.f:
---------------------------
     subroutine yo()
     write(*,*) 'yo'
     end
----------------------------
with

f2py -c yo.f -m yo

It segfaults at the second calling of yo.yo(). In fact, it segfaults
on exit even if I never reload the module. My guess would be that
something is expecting that library to still be linked, but I have no
idea where to look or how to change that expectation. If its not
already obvious from the above script, I should probably mention that
I'm using Linux and I could care less about platform portability.

Kevin
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