Re: a Query regarding COM Server and terminal services

From:

"Brian Muth" <bmuth@mvps.org>

Newsgroups:

microsoft.public.vc.atl

Date:

Thu, 11 Jun 2009 08:52:35 -0700

Message-ID:

<EA804E9B-AD26-4228-B7F6-1939D2AD76D3@microsoft.com>

"d" <d@discussions.microsoft.com> wrote in message
news:612762C3-D067-4BDE-B8DD-260F77AD2B8D@microsoft.com...

hello Brian ,

thanks for your reply. earlier we were using connection points to perform
task.

Why not do it that way?

then later we decided that if we could pass a interface pointer to the COM
server from the client. we would be able to differentiate it.

i have one more concept problem. i have a class which interect with a
service.
now if any of the COM server client connections to the service classs with
IServicePtr ptr(__uuidof(Service))

i have a function in the "IService" interface called
GetInterface(ISomeInterface ** psf)

now in the COM EXE server

CService::GetInterface(ISomeInterface ** psf)
{
return CSomeInterface::CreateInstance(psf);
}

in this case if there are 10 users who create the Service COM object will
have
10 different -2 instance of "CSomeInterface::CreateInstance(psf);" i mean
10
ISomeInterface interface. am i wrong here??

No, you are correct. That is the standard paradigm.

i want to instentiate only ONE "CSomeInterface" Object to be returned

Then change the implementation of CService::GetInterface(ISomInterface
**psf). Perhaps it might look something like:

static ISomInterface *pSingleton = null;

CService::GetInterface(ISomeInterface (** psf)
{
    if (pSingleton == null)
    {
        CSomeInterface::CreateInstance(pSingleton);
    }
    return pSingleton;
}

Howeever, I'd like to ask why? Why do you want the same COM object to be
handed out to all your clients? It can be done, but I suspect there is a
much better way to meet your requirements, which you haven't described.