COM Enhancement patch

Marcus Meissner meissner at
Fri Nov 15 03:29:44 CST 2002

On Fri, Nov 15, 2002 at 09:53:33AM +0100, Lionel Ulmer wrote:
> > > Well, I was hoping some of the COM experts would comment on that. If
> > > I understand it right you are avoiding writing some thunking routines
> > > for older interfaces, at the cost of an extra pointer access in every
> > > function. I'm not convinced it's a good trade-off, but I'd like to
> > > hear other opinions.
> Well, in the other case, the thunked interface will also have a performance
> trade-off as it will introduce extra pointer arithmetic and function calls
> on each COM call. Of course, the 'dominant' one will not have any
> performance penalty at all.
> > As for increased function sharing and reduced thunks usage...
> > True, but the number of functions is not really annoying or problematic.
> Well, in some cases like in D3DDevice where you have 34 methods that are
> shared between different interfaces, it starts to get a little bit annoying
> to write 34 thunks :-)
> In any case, for the moment I rewrote most of the COM part for the Direct3D
> code using Christian's patch (as it made my life much easier :-) ). Now, if
> it won't go into the tree, I could add thunking to it (should not be that
> hard). Just take a decision soon so as to not have a 11 klines patch lying
> in my tree for too long...

If this makes your work easier I would just say go for it.

Ciao, Marcus

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