InstallShield and ole question...

Gavriel State gav at
Tue May 1 08:38:51 CDT 2001

Dan Kegel wrote:
> Jeremy White wrote:
> > With COM, the other issue is that someone needs to look at the MS patents
> > in this area.  Mainsoft is telling people that they can't use Wine to
> > port COM code, because Microsoft holds patents on some of the Vtable
> > logic used in COM (and no, I don't have any more detail than that,
> > this came to me third hand).
> > I've also asked the FSF for help tracking this FUD down and refuting it.
> For the curious:
> Snooping on his conversation using, I see it's patent number
> 5297284 he's worried about.

Hmmm - a few points to consider:

 1) The patent seems very much oriented towards compilers for object
    oriented languages.  I'm not sure how broadly that patent can be
    applied to code like ours that uses C to mimic the behaviour of 
    a OO language.  If there's an issue anywhere, I'd suspect that
    it's with g++, not Wine.

 2) Even with g++, the work described in the patent that's actually new
    (ie: wasn't implemented in other C++ compilers as of April 1991) mostly
    seems to cover multiple inheritance related issues - adjusting the 
    this pointer to the right part of an MI object's vtable, etc.  Since
    a COM interface is nothing but a flat array of function pointers,
    I fail to see any relevance at all to the Wine side of things.

 3) At least some of the g++ people seem to know something about this 
    patent.  There's a small thread here:

    And there's some further discussion wrt the ia64 C++ abi here:

 4) G++ was around for quite some time prior to the patent application.
    You can download an archival copy of g++ 1.39.0, which predates the
    patent here:
Anyhow, this is just from a very cursory analysis, but I'd say that the
Mainsoft FUD is just that: FUD.


Gavriel State, CEO
TransGaming Technologies Inc.
gav at

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