[cairo] Cannot import PyCairo in Python 3.0 (ImportError: dlopen / "Expected in: flat namespace")

[Philipp Schumann]

Hi, thanks for getting back!

Sounds reasonable, except all "Pycairo" is *actually* "doing" is  
importing a dynamic library (.so) written in and compiled from C. I  
can't imagine the semantics of that having changed to drastically in  
3.0, so I was wondering whether anyone here has some experience with  
3.0 as well and could give me a hint. Maybe I'll ask in some 3.0  
mailing lists or forums, too.

As you said, "it's a fairly straightforward binding". So I can't  
comprehend how this C library possibly *could* (technically) be  
"recompiled against" py3k. "Pycairo" itself is "just" the __init__ one- 
liner, no? 2to3 changed that for me so I don't think that's the problem.


 > At the very least you will need to compile pycairo/cairo yourself and
 > pycairo against py3k. It's a fairly straightforward binding so errors
 > should be fixable. That being said it won't be trivial. Any reason  
why
 > you are moving to Python 3.0 so fast? Since it's a breaking release
 > expect a few years before everything ported.

Yeah, basically my code base is still in its early stages but will be  
project of a few years to come. I've only got 1 or 2 months worth of  
code at that point, I'm far from release to production but I know I  
will eventually have to upgrade to py3k, so I'd rather have it there  
*now*, even if rough around the edges. Most of the other libs I use  
were either already "ported" or I could do it myself painlessly with  
2to3, no headaches or troubleshooting involved, thankfully. That  
includes mako, Werkzeug, couchdb, simplejson, httplib2. So for me the  
upgrade isn't that "breaking". Except for Cairo, but heck, at the end  
of the day it's "just" C bindings, so I'm thinking it should be  
possible to somehow "rebind" that, no?

Any of the Cairo core hackers fancy giving it a spin? Maybe it's an  
easy hack, otherwise don't bother and I'll revert to 2.6 for now...  
Shamefully, I've never done any C or else I'd already be getting my  
teeth into that at that point now.


 >
 > ~G
 >
 > On Sun, Jan 4, 2009 at 6:56 PM, Philipp Schumann <phil at  
roxority.com> wrote:
 > > Hello,
 > >
 > > I'm in the process of moving my code base to Python 3.0. On Mac  
OS X
 > > 10.5.6, I've upgraded both Cairo and PyCairo to 1.8.0; then in /
 > > Library/Frameworks/Python.framework/Versions/3.0/lib/python3.0/ 
site-
 > > packages/ ran 2to3 -w cairo and removed the __init__.pyc file.
 > >
 > > After restarting Eclipse Ganimede /w Pydev and trying to run my  
code,
 > > I got the following ImportError:
 > >
 > >   File "/Users/roxor/dev-py/metaleap/src/metaleap/core/gfx.py",  
line
 > > 2, in <module>
 > >     import cairo
 > >   File "/Library/Frameworks/Python.framework/Versions/3.0/lib/
 > > python3.0/site-packages/cairo/__init__.py", line 1, in <module>
 > >     from ._cairo import *
 > > ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/ 
3.0/
 > > lib/python3.0/site-packages/cairo/_cairo.so, 2): Symbol not found:
 > > __Py_ZeroStruct
 > >   Referenced from: /Library/Frameworks/Python.framework/Versions/ 
3.0/
 > > lib/python3.0/site-packages/cairo/_cairo.so
 > >   Expected in: flat namespace
 > >
 > > Any ideas how this can be fixed "quick-and-dirty"-ish? I'm far  
from a
 > > production release anyway so I don't have to wait until pycairo
 > > "officially" supports Python 3000. Just any ideas to quickly and
 > > easily get Python 3.0 / pycairo to work with the current _cairo.so
 > > dynamic library would be *highly* appreciated...
 > >
 > > Thanks a lot,
 > > Phil
 > >
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 > > cairo mailing list
 > > cairo at cairographics.org
 > > http://lists.cairographics.org/mailman/listinfo/cairo
 > >