[Extending] Py_BuildValue( "((OiiO))",...) creates empty string?

[Mike C. Fletcher]

I'm working on a C module, and have come across something I don't 
understand.  Basically, I have a method definition/specification which 
says I will pass my clients a 4-item tuple to their append method.

So, I want to call:
	PyObject_CallObject( objectToCall, parameter );

With a parameter equal to:
	(("this",1,2,[]),)
That is, a singleton tuple with a 4-item tuple as the first (and only) 
item.  Now, the docs for Py_BuildValue say I can create arbitrarily 
nested tuples, so I would expect this:

	parameter = Py_BuildValue( "((OiiO))", tagobj, childStart, childPosition, 
childResults );

to create the appropriate tuple-structure.  Unfortunately, it doesn't. 
Instead it creates an empty string as far as I can tell (that's what my 
Python test code receives, anyway).

I also tried it like this:

	parameter = Py_BuildValue( "(N)", Py_BuildValue( "(OiiO)", tagobj, 
childStart, childPosition, childResults ));

And again, got the same result (an empty string passed to my method).

Any clues from the C gurus as to what I'm doing wrong?

With thanks,
Mike
_______________________________________
   Mike C. Fletcher
   http://members.rogers.com/mcfletch/