Re: CoCreateInstance inside a COM dll?

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.atl
Date:
Fri, 24 Aug 2007 14:32:14 -0400
Message-ID:
<#0$1Y0n5HHA.600@TK2MSFTNGP05.phx.gbl>
Donos <donguy76@gmail.com> wrote:

Ok here i am going to get a interface pointer using the following
function, This is inside the COM.

STDMETHOD GetMyInterface(IMyInterface** pMyInterface, VARIANT_BOOL*
pResult)
{
-------------------------
QueryInterface(__uuidof(IMyInterface), (void **)&pMyInterface);


Drop the ampersand. pMyInterface is already a pointer to a pointer, you
should not take its address.

Also, I don't see you set *pResult to anything, nor return any HRESULT.

Now inside Client app, i add the code as,

GetInterface()
{
IMyInterface** pInterface;
HRESULT hr = m_pFirstInterface->GetMyInterface(&pInterface,
(VARIANT_BOOL*)&rc);
}


GetMyInterface takes IMyInterface**. You are passing IMyInterface***.

Where is rc declared?

In any case, I don't see the point of the exercise. Why do you need
GetMyInterface method? Why can't the client simply do

IMyInterface* pInterface = 0;
HRESULT hr = m_pFirstInterface->QueryInterface(__uuidof(IMyInterface),
(void**)&pInterface);

--
With best wishes,
    Igor Tandetnik

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