Sequence Protocol, assign item

Torsten Mohr tmohr at s.netic.de
Mon Sep 6 20:49:02 CEST 2004


Hi,

thanks for your answer!

> You don't want to use PyArg_ParseTuple here, because 'val'
> isn't wrapped in a tuple, it's the bare value of the RHS.
> Instead you want
> 
> v = PyInt_AsLong(val);
> if (PyErr_Occurred())
> return -1;

That exactly solves the problem.

> Also note the -1 return value (not 0) to signal an error.

I also found this by looking into the sources of Objects/listobject.c,
thanks for that other hint.

>> In part A some INCREF/DECREF stuff is done, but i think i don't need
>> this as the PyObjects are only temporarily.
> 
> That's correct in this case.
> 
>> Exception exceptions.SystemError: 'new style getargs format but argument
>> \ is not a tuple' in 'garbage collection' ignored
> 
> That's because you were passing PyArg_ParseTuple something
> that wasn't a tuple. (The error message talks about argument
> formats because PyArg_ParseTuple is intended for processing
> argument lists, and in normal use it can't ever get passed
> anything other than a tuple.)

Thanks for your hint, that helped me fix the problem.  But where
can i learn more about the internals?  Maybe i just assumed this
as a Py_Object* always needed to be transformed the way i did
before.
I did not find any help regarding this in the documentation and also
in the sources it was not obvious to me.


Best regards,
Torsten.




More information about the Python-list mailing list