Thank you Robert, the explanation on how and where to use cdef was most helpful. I think it has just clicked(with a flag waving 'idiot').
The PyCObject concept is a nice idea, removing cdef foo_t *foo from outside of __init__ ? However, I see implications in memory deallocation. How does cython currently handle memory deallocation? I assume the best practice would be for users to deallocate memory in the class __del__ method (calling the appropriate wrapped c library destructor). Otherwise does cython simply free(foo) or interprets the language to build a depth first deallocation method? I guess it should do the simplest free(foo), if the developer was lazy not to deallocate memory, they can suffer with memory leaks. I think I might have answered my own question here... Richard On Thu, Jul 23, 2009 at 12:43 PM, Robert Bradshaw<rober...@math.washington.edu> wrote: > On Jul 23, 2009, at 3:39 AM, Richard Clarke wrote: > >> Hi, >> >> Can anyone point out where I am going wrong? > > Sure. There is no way convert a pointer to a Python object. (Perhaps > we could support this via http://www.python.org/doc/2.6/c-api/ > cobject.html , but certainly that'll take a lot of thought). > > You need to make Bar into a cdef class for it to have a foo_t* > member. Also, if a return type is foo*, you need to make it a cdef > function. I would recommend reading http://docs.cython.org/ . > >> // foo.pyx >> >> cdef extern from "foo.h": >> ctypedef struct foo_t: >> int fd >> >> foo_t* init() >> >> class Bar: > > > cdef class Bar: > > cdef foo* __foo > >> def __init__(self): >> self.__foo = self.__open() >> >> def __open(self): > > > cdef foo* open(self): > >> cdef foo_t *foo >> foo = init() >> return foo >> >> >> Results in the error: >> /test/foo.pyx:14:12: Cannot convert 'foo_t *' to Python object >> >> Cython version 0.9.6.14 >> >> Thank you, >> Richard. >> _______________________________________________ >> Cython-dev mailing list >> Cython-dev@codespeak.net >> http://codespeak.net/mailman/listinfo/cython-dev > > _______________________________________________ > Cython-dev mailing list > Cython-dev@codespeak.net > http://codespeak.net/mailman/listinfo/cython-dev > _______________________________________________ Cython-dev mailing list Cython-dev@codespeak.net http://codespeak.net/mailman/listinfo/cython-dev
