Re: xPLLib v3.0 Public Beta

[Tom Van den Panhuyzen <tomvdp@xxxxxxxxx>]

If the code crashes because of a programming error (say some strange
packet that makes it crash) it will release the mutex.
I think the only exception is when you actually kill it via task
manager.  But I should check that.  Because mutexes are managed by
Windows and not the .net framework or some other higher layer it is
pretty reliable.

Taking the whole mutex-thing back out of V3 isn't a big deal.  It does
mean that there will be a release of both a new version of xPL Hub and
xPL Lib.  Both have had a considerable review.  xPL Lib more than xPL
Hub.

Tom
(2 releases! complications complications!  lol)


On Tue, 30 Nov 2004 15:29:20 -0000, Mal Lansell <mlansell@xxxxxxx>
wrote:
> OK, that's that complaint dealt with ;-)
>
> One more thing - if a hub stops working, it's very likely to be stuck,
or
> have crashed, i.e will not necessarily have quit in a clean way.  In
that
> case it won't it still be holding the mutex?  That means hub transfer
only
> takes place when the hub application is closed, and is not a
protection
> against errors in the hub code.
>
> It seems to me that making the hub code more robust and fault tolerant
in
> the first place would be a more useful approach.
>
> Mal
>
>
>
>
>
>
>
>
> ----- Original Message -----
> From: "Tom Van den Panhuyzen" <tomvdp@xxxxxxx>
> To: <ukha_xpl@xxxxxxx>
> Sent: Tuesday, November 30, 2004 3:06 PM
> Subject: Re: [ukha_xpl] xPLLib v3.0 Public Beta
>
>
> >
> > Mutexes are really a core element in Windows.
> > See:
> >
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/bas
> e/mutex_objects.asp
> >
> >
> > On Tue, 30 Nov 2004 14:49:28 -0000, Mal Lansell
<mlansell@xxxxxxx>
> wrote:
> > >
> > > ----- Original Message -----
> > >
> > >
> > > From: "Tom Van den Panhuyzen"
<tomvdp@xxxxxxx>
> > > To: <ukha_xpl@xxxxxxx>
> > > Sent: Tuesday, November 30, 2004 2:31 PM
> > > Subject: Re: [ukha_xpl] xPLLib v3.0 Public Beta
> > >
> > >
> > > > - no more seperate xpl hub service
> > > > - no single critical service
> > > > - every xpl msg gets transmitted because from the
moment there is an
> > > > xpl app there is also an xpl hub
> > > > - if you have only one xpl app, things work like
expected
> > > > - if you have 2, switch them on in any order
> > > > - if you have more, idem
> > > > - completely transparent to the developer, just use an
xplListener
> > > > object like before
> > > > - if one hub goes down, the next re-uses the client
list from the
> > > > previous, so lost msgs are reduced to the minimum
> > > >
> > > > I honestly think V3 is simpler and more robust.
> > > >
> > >
> > > The mutex system you use is a .NET feature isn't it?
> > >
> > > What about non-.NET apps?  If we were to go down the route
of allowing
> any
> > > xPL app to be a hub, and for the hub to migrate if the
current one
> fails,
> > > then I say it would be best if all xPL apps could do this. 
That means
> using
> > > a system that doesn't rely on a .NET feature.
> > >
> > > If a .NET system were devised, then the problem of
incompatible hubs
> would
> > > eventually go away - we could update the existing apps/libs
and make it
> a
> > > rule of hub implementation that being able to take over as
hub is
> supported.
> > >
> > > Mal
> > >
> > >
> >
> >
> >
> > xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
> http://www.xpl.myby.co.uk
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> >
> >
> >
> >
> >
> >
>
>
>
>
>
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