[Pyrex] [Pyrex, Cython]Subclass basic exceptions inside Pyrex

[Greg Ewing]

Daniele Pianu wrote:

> I've some problems subclassing the basic extension type. The idea is
> to create my own exception hierarchy inside the Pyrex code, extending
> basic Python exception objects. This is my code
> 
>       cdef extern class __builtin__.Exception [object PyExc_Exception]:
>         pass
>       cdef class MyPyrexException( Exception ):
>         pass


There are various things going on here:

1) The object struct for the builtin exception type isn't PyExc_Exception,
it's PyBaseExceptionObject.

2) It's declared using a typedef.

3) It's declared in pyerrors.h, which doesn't get included from Python.h.

Taking all that into account, you need to do something
like this:

   cdef extern from "pyerrors.h":
     ctypedef class __builtin__.Exception [object PyBaseExceptionObject]:
       pass

-- 
Greg