problem with Py_BuildValue

[Cédric Lucantis]

> Thank you. At least I can exclude another few error sources, now.
>
>
>> I see nothing wrong with your code so I'd say it is somewhere else (did
>> you snip any code between the end of the loop and the return?).

>No. (Apart from freeing allocated memory.)

I'm pretty sure we'll find something interesting here :)

> > and if it doesn't help trace the content of your list
> > after each iteration to see when the bad things happen (you can check the
> > reference count of an object with obj->ob_refcnt).
>
> Seems ok. What I did to check this was placing this after building the
> list:
>
> for (i=0; i < limit; i++) {
>     dummy = PyList_GetItem(python_return_value, i);
>     printf("%f\n", PyFloat_AsDouble(dummy));
>     Py_CLEAR(dummy);
> }

PyList_GetItem returns a borrowed reference so you shoud _not_ unref it (this 
explains the refcnt -1 I think)

Here's the code producing your message (from Objects/object.c in the python 
sources) :

/* Implementation of PyObject_Print with recursion checking */
static int
internal_print(PyObject *op, FILE *fp, int flags, int nesting)
{
	<snip>
	if (op->ob_refcnt <= 0)
		/* XXX(twouters) cast refcount to long until %zd is
		   universally available */
		fprintf(fp, "<refcnt %ld at %p>", (long)op->ob_refcnt, op);
	}
	<snip>
}

I don't really understand its purpose, but it confirms that it's a ref count 
problem. Maybe the full source of your function could help ?

-- 
Cédric Lucantis