Re: marshalling an interface pointer

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.atl
Date:
Tue, 16 Mar 2010 18:41:53 -0400
Message-ID:
<e$AbhnVxKHA.3564@TK2MSFTNGP05.phx.gbl>
Drew Hohmann <drew@med-associates.com> wrote:

I've created an ATL project using VS2008, with the option merge
proxy/stub checked. All of the COM interfaces are set to
CComObjectRootEx<CComMultiThreadModel>


This doesn't by itself mean much. How is your server registered? What's =
the value of ThreadingModel registry entry for the CLSIDs in question?

[
object,
uuid(B7A09AF5-2868-11DF-8A39-001CC0A3A714),
  oleautomation,
dual,
nonextensible,
helpstring("IMEDPositionDevice Interface"),
pointer_default(unique)
]
interface IMEDPositionDevice : IDispatch{
/*various functions*/
  [id(15), helpstring("method Read")] HRESULT Read([in] REFIID riid,
[out] IUnknown** pData);


This method is not automation compatible. You shouldn't be using a =
method like this in an interface you claim to be [oleautomation].

COM is using a different thread to call the read function with


What do you mean, a different thread? Different from what?

so the
pointer returned from spdev->Read is invalid.


Invalid in what way? How do you determine this?
--
With best wishes,
    Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not =
necessarily a good idea. It is hard to be sure where they are going to =
land, and it could be dangerous sitting under them as they fly overhead. =
-- RFC 1925

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