[Twisted-Python] No-op TimerService on Windows?

[Eric Faurot]

On 5/4/06, glyph at divmod.com <glyph at divmod.com> wrote:

> On Thu, 4 May 2006 11:05:21 +0200, Eric Faurot <eric.faurot at gmail.com> wrote:
>
> >In the process of exploring my options for deploying twisted
> >applications on Windows, I noticed that when running the application,
> >_twistw (line 43) also starts a TimerService around a no-op:
> >
> >app.startApplication(internet.TimerService(0.1, lambda:None), 0)
> >
> >I suppose there is very good reason to do so, but I do not see it.
> >Can somebody enlighten me?
>
> There should be a comment or something to this effect, but:
>
> On Windows, the "signal" handling that Control-c triggers doesn't actually interrupt select().  That timer is there to keep the timeout low so that the server responds in a timely fashion when the user hits Control-c on the console, even if nothing else is happening.

Ok, but as far as I can see, it is redundant with way select is
wrapped on win32 (in selectreactor). BTW, I am not windows-savvy, but
are the arguments to select (r,w,w) really correct? not (r,w,e)?

def win32select(r, w, e, timeout=None):
    """Win32 select wrapper."""
    if not (r or w):
        # windows select() exits immediately when no sockets
        if timeout is None:
            timeout = 0.01
        else:
            timeout = min(timeout, 0.001)
        sleep(timeout)
        return [], [], []
    # windows doesn't process 'signals' inside select(), so we set a max
    # time or ctrl-c will never be recognized
    if timeout is None or timeout > 0.5:
        timeout = 0.5
    r, w, e = select.select(r, w, w, timeout)
    return r, w + e, []


Eric.