[Pyrex] Functions pointers

[Daniele Pianu]

I'm trying to wrap a C function that requires a C function pointer as
argument. I've wrote a pyrex extension with a dictionary where every key is
a C function name, and every entry is a C function pointer, stored as a
long. I call the C function from python passing the function name and the
necessary data.

An example:

-------- c_funcs.h ---------

int returnFoo(int);

int returnBar(int*);

char* returnFooBar(char*);

int callFoo(int(*)(int), int);

int callBar(int(*)(int*), int*);

char* callFooBar(char*(*)(char*), char*);


------- c_funcs.c -------
#include <c_funcs.h>

int returnFoo(int foo){
  return foo;
}

int returnBar(int* bar){
  if (bar)
    return *bar;
}

char* returnFooBar(char* fooBar){
  if (fooBar)
    return fooBar;
}

int callFoo(int(*func)(int), int foo){
  return (*func)(foo);
}

int callBar(int(*func)(int*), int* bar){
  return (*func)(bar);
}

char* callFooBar(char*(*func)(char*), char* FooBar){
  return (*func)(FooBar);
}

------- funcs.pyx ----------
cdef extern from "c_funcs.h":
  int callFoo(int(*)(int), int)
  int callBar(int(*)(int*), int*)
  char* callFooBar(char*(*)(char*), char*)

cdef class funcs:
  cdef object funcsDict
  def __init__(self):
      cdef unsigned long fooPointer
      fooPointer = <unsigned long>&callFoo
      self.funcsDict = {}
      self.funcsDict['returnFoo'] = fooPointer
      # Here the python interpreter prints an integer, not a long as
expected!!!
      print self.funcsDict['returnFoo']

  def pyCallFoo(self, foo):
      # The call to C function produces a Segmentatio Fault
      return callFoo(<int(*)(int)>self.funcsDict['returnFoo'], foo)

How can I solve the problem? Every advice about alternative implementation
is also appreciated :)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.copyleft.no/pipermail/pyrex/attachments/20080411/225693ad/attachment.html