Thanks Adam

but....

I'm still confused because...

There is a new rule in version 2.3.5.  Which is one interpreter with 
many thread states are supported for the GIL functions.  So this code 
breaks that rule since this if statement is checking if the 
interpreters are different for the current GIL state and the new ts 
which it can't be (i.e. unsupported).   See this email that points to 
the python documentation for 2.3.5 regarding this "new" rule...

http://mail.python.org/pipermail/python-dev/2005-May/053840.html

Here is the extract of the email pertaining to this issue...

The documentation (http://docs.python.org/api/threads.html) states
"Note that the PyGILState_*() functions assume there is only one
global interpreter (created automatically by Py_Initialize()). Python
still supports the creation of additional interpreters (using
Py_NewInterpreter()), but mixing multiple interpreters and the
PyGILState_*() API is unsupported. ", so it looks like that using the
PyGilState_XXX functions in the core threadmodule.c means the
Py_NewInterpreter() call (i.e. multiple interpreters) is no longer
supported when threads are involved.

So regardless if we use the GIL functions or the lower level functions 
it all eventually boils down to this Swap function which has this 
condition that doesn't match what the documentation is stating. So 
which way is it? Can't have it both ways.

It seems since 2.3.5 they don't want you to use multiple interpreters 
is my guess when threading is involved.