[Cython] Generated C++ code incompatible with Clang

[Robert Bradshaw]

It's not a big problem, but it'll be an ugly and invasive amount of
bookkeeping to manage these top-level typedefs per type deletion.

On Tue, May 7, 2013 at 1:38 PM, Hannes Röst
<hroest_nospam2333 at quantentunnel.de> wrote:
> Hi Robert
>
> After some internal discussion, we have not found an obvious way to not have
> the extra typedef. Is this a big problem?
>
> Maybe there are other people on the list that are more fluent in C++ and
> could think of a way to do it?
>
> Greetings
>
> Hannes
>
> On 30 April 2013 07:48, Robert Bradshaw <robertwb at gmail.com> wrote:
>>
>> On Fri, Apr 12, 2013 at 8:04 AM, Hannes Röst
>> <hroest_nospam2333 at quantentunnel.de> wrote:
>> > Dear mailing list
>> >
>> > In the process of developing a rather large Cython project where we wrap
>> > the
>> > scientific OpenMS library (http://sourceforge.net/projects/open-ms/)
>> > using
>> > Cython, we have come across an issue with the C++ code that is generated
>> > by
>> > Cython. The issue is that Cython generates C++ that is not compatible
>> > with the
>> > Clang compiler.
>> >
>> > I hope this is the correct mailing list to report this issue since it
>> > seems to
>> > be a bug in Cython and not in Clang (after some discussion we have
>> > concluded
>> > that Clang is most likely correct in rejecting the generated code).
>> > Since we do
>> > not have access to the issue tracker, we hoped posting our issue here
>> > would
>> > clear up matters.
>> >
>> > The issue occurs with the following minimal testcase:
>> >
>> > from libcpp.vector cimport vector as libcpp_vector
>> > from cython.operator cimport dereference as deref, preincrement as inc
>> >
>> > cdef class TestClass:
>> >
>> >     cdef libcpp_vector[float] inst
>> >
>> >     def __iter__(self):
>> >         it = self.inst.begin()
>> >         while it != self.inst.end():
>> >             yield deref(it)
>> >             inc(it)
>> >
>> > When compiled with Cython to C++, it generates C++ that cannot be
>> > compiled with
>> > Clang (however it seems that gcc and MSVS accept the code). It seems
>> > that the
>> > same issue with Clang was already discussed here:
>> > https://bugzilla.mozilla.org/show_bug.cgi?id=623303 and the conclusion
>> > was that
>> > Clang is correct in reporting the code as erroneous.
>> >
>> > In the above case, the invalid C++ code that gets generated is:
>> >
>> >   p->__pyx_v_it.std::vector<float>::iterator::~iterator();
>> >
>> > The correct code for the above case would probably be (this is just a
>> > suggestion, it compiles with gcc and clang on our machines and our tests
>> > run
>> > through with it):
>> >
>> >   typedef std::vector<float>::iterator _it;
>> >   p->__pyx_v_it.~_it();
>> >
>> >
>> > We have tested it with the 0.18 release as well as the newest 0.19b2
>> > build from
>> > github (58131b68dc033fc7ca269d875a2aab2b4e9646a2) and the results were
>> > the
>> > same.
>>
>> Thanks for the report. Can you think of a solution that doesn't
>> require a special typedef declaration for each type you might want to
>> call a destructor on?
>> _______________________________________________
>> cython-devel mailing list
>> cython-devel at python.org
>> http://mail.python.org/mailman/listinfo/cython-devel
>
>
>
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