General question of "SystemError:NULL result..."

[Fredrik Lundh]

gmol at my-deja.com wrote:
> Hi all, disclaimer, I am new to python so I may be doing something
> severly stupid.

unless you've written the extension module, it's not
really your fault...  read on.

> I have installed VTK and python on my sys,and some of the python
> examples work, and some don't...the ones that don't say always say
> something like:
>
>   File "KSpline.py", line 106, in ?
>     profileTubes.SetInput(profileData)
> SystemError: NULL result without error in call_object
>
> Now, no one has been able to figure this out on the VTK list...but I do
> know that people can run the same examples on the same python under the
> same platform (linux) and the same Mesa...

technically, this means that an extension library returns NULL
to Python, without setting the exception status.  it's a bug in
the extension library.

(it's probably caused by a configuration problem of some kind,
but the library should tell you so, rather than returning bogus
values to the python interpreter...)

</F>