[Python-Dev] Possible C API problem?

[Gary Robinson]

> You are doing something wrong. As getSumChiSquare is a METH_NOARGS
> method, it shouldn't have a PyObject*args argument.

While I am aware enough of your general expertise to be surprised if 
you were in error in your statement below about VAR_NOARGS, your 
statement obove does seem to contradict the docs:

METH_VARARGS
 This is the typical calling convention, where the methods have the  
type PyCFunction. The function expects two  PyObject* values. The first 
one is the self object for  methods; for module functions, it has the 
value given to  Py_InitModule4() (or NULL if  Py_InitModule() was 
used). The second parameter  (often called args) is a tuple object 
representing all  arguments. This parameter is typically processed 
using PyArg_ParseTuple() or PyArg_UnpackTuple.

...

 METH_NOARGS
 Methods without parameters don't need to check whether arguments are  
given if they are listed with the METH_NOARGS flag. They  need to be of 
type PyCFunction. When used with object  methods, the first parameter 
is typically named self and will  hold a reference to the object 
instance. In all cases the second parameter will be NULL.

----

(http://python.fyxm.net/doc/2.3.5/api/common-structs.html#l2h-832

In other words the docs seem to explicitly state that the args will be 
supplied and what they will contain, so I'd assume that the C method 
should have them in their declaration. Moreover, METH_NOARGS needs to 
correspond to type PyCFunction, and the definition of type PyCFunction 
states that it must receive two args of PyObject*.

Are the docs wrong or am I misreading them? Or are you wrong?

Re your other comments, as mentioned in my personal email, the word 
done by folks in a couple of python forums in running tests does seem 
to confirm that there is some kind of bug involving gcc 3.3. The bus 
error appears independently of whether VAR_METHARGS or VAR_VARARGS is 
used. Also, (again as mentioned in my personal email) I do have 4 F/T 
experienced people working on this project, none of whom has the 
expertise to resolve this. Given that it looks like a real bug was 
uncovered, I think it was appropriate to post on the python forums 
about this. I only posted to python-dev because it was suggested that I 
do so by someone on the C++ sig.

Gary



-- 

Gary Robinson
CTO
Emergent Music, LLC
grobinson at goombah.com
207-942-3463
Company: http://www.goombah.com
Blog:    http://www.garyrobinson.net