[Python-Dev] Twisted Isn't Specific (was Re: Trial balloon: microthreads library in stdlib)

["Martin v. Löwis"]

Larry Hastings schrieb:
> Oof!  I'm embarrassed to have forgotten that.  But that's not a fatal 
> problem.  It means that on Windows the PerfectReactor must service the 
> blocking GetMessage loop, and these other threads notify the 
> PerfectReactor of new events by sending a message. 
...
> I'd be interested to hear about other situations where threading would 
> cause a problem.  My suspicion is that Windows is the hard one, and as 
> I've shown that one is solvable.

As others have reported: if you have a gtk reactor and a wx reactor
to support, in addition to a "regular" Win32 reactor (e.g. PythonWin),
your approach still won't work. They all do GetMessage behind the
scenes (sp?), yet you would run them in multiple threads, so they
get their own messages. Plus they are not thread-safe.

Speaking of which: Tcl has a "multiple interpreter" model where each
interpreter is single-threaded. You can build Tcl either single-
or multi-threaded; for the multi-threaded Tcl, you still can't
share data across threads directly, but instead, you create an
interpreter per thread. Then, all operations on that interpreter
must occur in this thread, including the reactor calls.

So if the PerfectReactor is to support Tcl/Tk, it needs to run
the Tcl even loop in the Tcl thread, which is normally the
main thread (in Tkinter, it's the thread where you originally
created the tkapp object). OTOH, PerfectReactor may also need
to run some Win32 event loop in the same thread.

Regards,
Martin