Library support for Python 3.x

Stefan Behnel stefan_ml at
Thu Jan 28 09:40:42 CET 2010

David Cournapeau, 28.01.2010 06:58:
> On Thu, Jan 28, 2010 at 7:38 AM, Terry Reedy wrote:
>> For a windows user who depends on pre-built binaries, every new release
>> breaks *every* library that is not pure Python and needs to be compiled.
> That's not windows specific - most packages which distribute binary
> packages need to package binaries for every minor version (2.4, 2.5,
> etc...). That's certainly the case for numpy and scipy. Python does
> not have a stable ABI across minor releases, only micro releases.

That doesn't completely match my experience. It's true that there is no
guarantee that the ABI will stay compatible, but when you compile lxml
against Py2.4 on a 32bit machine, it will continue to import in Py2.5 and
(IIRC) Py2.6. It won't be as fast and it won't use some newer features, but
it will work. Don't remember my experience with 2.3, though.

It obviously can't work the other way round, i.e. when compiling against
2.6, it will never work in 2.5 or earlier. But there is definitely a
certain degree of ABI compatibility available.


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