[python-win32] Trouble with SetWindowLong().

[Ben Timby]

IIUC, WndProc receives messages from the message pump. I am attempting
to override the default message handler with my own. The code I posted
is a contrived example. So really, I am not interested in the
correctness of it, but why does the call to SetWindowLong() fail the
way it does when I call it.

For a less contrived example, just google, and you will find many code
samples doing almost exactly what my sample does (and ostensibly not
failing).

Here is a good one:
http://wiki.wxpython.org/HookingTheWndProc

How can that code run while passing a function reference as the last
parameter, and mine fails? That is the underlying issue, not my sample
code.

I appreciate your bewilderment, but would be more interested in an
answer to my question.