Porting Python2 C-API/Swig based modules to Python 3
Hello,
I am trying to get a compiled module to work with Python3. The code I
am compiling was originally intended to be used in a Python 2.*
environment, but I updated all the Python 2.* elements and the swig
commands used by the setup.py script. I got the library to
successfully compile, but I am getting the following errors on import
(below). I am not sure how to trouble shoot this problem, and the
fact that only one symbol (_PyCObject_FromVoidPtr) is missing is
disconcerting. I Googled some, but the symbol mentioned only showed
up in a few posts, where linking was an issue. I have also gone
through the setup.py script and explicitly defined all the library
paths.
My questions:
- Has anyone ever ported Python 2* modules/libs to Python 3 that rely
on swig, and are there some changes in the C-API/swig I need to be
looking for to make this port successful?
- Does anyone have any advice/insght about how I can troubleshoot,
diagnose, and resolve this issue?
Thanks in advance,
-- Adam
0:pylibpcap-0.6.2$ python3
Python 3.2 (r32:88452, Feb 20 2011, 11:12:31)
[GCC 4.2.1 (Apple Inc. build 5664)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import pcap,py
Traceback (most recent call last):
File "", line 1, in
File
"/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/pcap.py",
line 25, in
_pcap = swig_import_helper()
File
"/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/pcap.py",
line 21, in swig_import_helper
_mod = imp.load_module('_pcap', fp, pathname, description)
ImportError:
dlopen(/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/_pcapmodule.so,
2): Symbol not found: _PyCObject_FromVoidPtr
Referenced from:
/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/_pcapmodule.so
Expected in: flat namespace
in
/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/_pcapmodule.so
>>> ^D
--
http://mail.python.org/mailman/listinfo/python-list
Re: Porting Python2 C-API/Swig based modules to Python 3
Thanks for the help. That information got me started in the right
direction. I put my notes up on paste bin for others to use in the
future.
For the future reference of others, I have included the pertinent
details below. My process for identifying the various issues was
compiling and running the project to see what was still broken after
each fix. I know this is not the most efficient way, but it worked
for this pylibcap since the code base was pretty small. I don't think
everything is completely fixed, but its a step in the right direction.
The initial hurdle I encountered was swig. I had to modify swig's
code output, because it was not using the PyCapsule_* API yet. I
found someones solution here: http://paste.pocoo.org/show/253494/.
After applying that fix, I found that the pcap_interface.c and pcap.i
files in the project were using some deprecated API calls. So I
converted the following APIs:
PyLong_AS_INT ==> PyLong_AsLong
PyInt_* ==> PyLong_*
PyString_* ==> PyBytes_* (initialily changed to PyUnicode_* but that
was wrong, because I needed the Raw Bytes)
I also had to change s# to y#. Before, s# stood for string and #, but
it now means unicode and number.
Hopefully these details will be helpful to others in the future.
Thanks again for the nudge,
-- Adam.
On Wed, Feb 23, 2011 at 11:58 AM, casevh wrote:
> On Feb 23, 8:54 am, Adam Pridgen
> wrote:
>> Hello,
>>
>> I am trying to get a compiled module to work with Python3. The code I
>> am compiling was originally intended to be used in a Python 2.*
>> environment, but I updated all the Python 2.* elements and the swig
>> commands used by the setup.py script. I got the library to
>> successfully compile, but I am getting the following errors on import
>> (below). I am not sure how to trouble shoot this problem, and the
>> fact that only one symbol (_PyCObject_FromVoidPtr) is missing is
>> disconcerting. I Googled some, but the symbol mentioned only showed
>> up in a few posts, where linking was an issue. I have also gone
>> through the setup.py script and explicitly defined all the library
>> paths.
>>
>> My questions:
>>
>> - Has anyone ever ported Python 2* modules/libs to Python 3 that rely
>> on swig, and are there some changes in the C-API/swig I need to be
>> looking for to make this port successful?
>>
>> - Does anyone have any advice/insght about how I can troubleshoot,
>> diagnose, and resolve this issue?
>>
>> Thanks in advance,
>>
>> -- Adam
>>
>>
>>
>> 0:pylibpcap-0.6.2$ python3
>> Python 3.2 (r32:88452, Feb 20 2011, 11:12:31)
>> [GCC 4.2.1 (Apple Inc. build 5664)] on darwin
>> Type "help", "copyright", "credits" or "license" for more information.>>>
>> import pcap,py
>>
>> Traceback (most recent call last):
>> File "", line 1, in
>> File
>> "/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/pcap.py",
>> line 25, in
>> _pcap = swig_import_helper()
>> File
>> "/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/pcap.py",
>> line 21, in swig_import_helper
>> _mod = imp.load_module('_pcap', fp, pathname, description)
>> ImportError:
>> dlopen(/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/_pcapmodule.so,
>> 2): Symbol not found: _PyCObject_FromVoidPtr
>> Referenced from:
>> /Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/_pcapmodule.so
>> Expected in: flat namespace
>> in
>> /Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/_pcapmodule.so
>>
>>
>>
>> >>> ^D- Hide quoted text -
>>
>> - Show quoted text -
>
> This is a change in the C-API in 3.2. See http://bugs.python.org/issue5630
>
> casevh
> --
> http://mail.python.org/mailman/listinfo/python-list
>
--
http://mail.python.org/mailman/listinfo/python-list
Re: Porting Python2 C-API/Swig based modules to Python 3
Link to pastebin: http://pastebin.com/102fhkgp
On Wed, Feb 23, 2011 at 6:18 PM, Adam Pridgen
wrote:
> Thanks for the help. That information got me started in the right
> direction. I put my notes up on paste bin for others to use in the
> future.
>
> For the future reference of others, I have included the pertinent
> details below. My process for identifying the various issues was
> compiling and running the project to see what was still broken after
> each fix. I know this is not the most efficient way, but it worked
> for this pylibcap since the code base was pretty small. I don't think
> everything is completely fixed, but its a step in the right direction.
>
> The initial hurdle I encountered was swig. I had to modify swig's
> code output, because it was not using the PyCapsule_* API yet. I
> found someones solution here: http://paste.pocoo.org/show/253494/.
> After applying that fix, I found that the pcap_interface.c and pcap.i
> files in the project were using some deprecated API calls. So I
> converted the following APIs:
>
> PyLong_AS_INT ==> PyLong_AsLong
> PyInt_* ==> PyLong_*
> PyString_* ==> PyBytes_* (initialily changed to PyUnicode_* but that
> was wrong, because I needed the Raw Bytes)
>
> I also had to change s# to y#. Before, s# stood for string and #, but
> it now means unicode and number.
>
>
>
> Hopefully these details will be helpful to others in the future.
> Thanks again for the nudge,
>
> -- Adam.
>
> On Wed, Feb 23, 2011 at 11:58 AM, casevh wrote:
>> On Feb 23, 8:54 am, Adam Pridgen
>> wrote:
>>> Hello,
>>>
>>> I am trying to get a compiled module to work with Python3. The code I
>>> am compiling was originally intended to be used in a Python 2.*
>>> environment, but I updated all the Python 2.* elements and the swig
>>> commands used by the setup.py script. I got the library to
>>> successfully compile, but I am getting the following errors on import
>>> (below). I am not sure how to trouble shoot this problem, and the
>>> fact that only one symbol (_PyCObject_FromVoidPtr) is missing is
>>> disconcerting. I Googled some, but the symbol mentioned only showed
>>> up in a few posts, where linking was an issue. I have also gone
>>> through the setup.py script and explicitly defined all the library
>>> paths.
>>>
>>> My questions:
>>>
>>> - Has anyone ever ported Python 2* modules/libs to Python 3 that rely
>>> on swig, and are there some changes in the C-API/swig I need to be
>>> looking for to make this port successful?
>>>
>>> - Does anyone have any advice/insght about how I can troubleshoot,
>>> diagnose, and resolve this issue?
>>>
>>> Thanks in advance,
>>>
>>> -- Adam
>>>
>>>
>>>
>>> 0:pylibpcap-0.6.2$ python3
>>> Python 3.2 (r32:88452, Feb 20 2011, 11:12:31)
>>> [GCC 4.2.1 (Apple Inc. build 5664)] on darwin
>>> Type "help", "copyright", "credits" or "license" for more information.>>>
>>> import pcap,py
>>>
>>> Traceback (most recent call last):
>>> File "", line 1, in
>>> File
>>> "/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/pcap.py",
>>> line 25, in
>>> _pcap = swig_import_helper()
>>> File
>>> "/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/pcap.py",
>>> line 21, in swig_import_helper
>>> _mod = imp.load_module('_pcap', fp, pathname, description)
>>> ImportError:
>>> dlopen(/Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/_pcapmodule.so,
>>> 2): Symbol not found: _PyCObject_FromVoidPtr
>>> Referenced from:
>>> /Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/_pcapmodule.so
>>> Expected in: flat namespace
>>> in
>>> /Library/Frameworks/Python.framework/Versions/3.2/lib/python3.2/site-packages/_pcapmodule.so
>>>
>>>
>>>
>>> >>> ^D- Hide quoted text -
>>>
>>> - Show quoted text -
>>
>> This is a change in the C-API in 3.2. See http://bugs.python.org/issue5630
>>
>> casevh
>> --
>> http://mail.python.org/mailman/listinfo/python-list
>>
>
--
http://mail.python.org/mailman/listinfo/python-list
