Re: ATL com server can pass interface as parameters?

From:

ceasar.tw@gmail.com

Newsgroups:

microsoft.public.vc.atl

Date:

18 Apr 2007 10:01:33 -0700

Message-ID:

<1176915693.218122.69230@p77g2000hsh.googlegroups.com>

Hi! Igor,
Thank for your help.

My code is like following:

Server side
========
class CMy2 : IMy2
{
    // IUnknown

    HRESULT STDMETHODCALLTYPE QueryInterface(const IID& iid, void**
ppv) { return S_OK; }
    ULONG STDMETHODCALLTYPE AddRef() { return 1; }
    ULONG STDMETHODCALLTYPE Release() { return 1;
    // IDispatch
    HRESULT STDMETHODCALLTYPE GetTypeInfoCount(UINT *pctinfo){ return
S_OK; };
    HRESULT STDMETHODCALLTYPE GetTypeInfo(UINT iTInfo, LCID lcid,
ITypeInfo **ppTInfo){ return S_OK; };
    HRESULT STDMETHODCALLTYPE GetIDsOfNames(REFIID riid, LPOLESTR
*rgszNames, UINT cNames, LCID lcid, DISPID *rgDispId){ return S_OK; };
    HRESULT STDMETHODCALLTYPE Invoke(DISPID dispIdMember, REFIID riid,
LCID lcid, WORD wFlags, DISPPARAMS *pDispParams, VARIANT *pVarResult,
EXCEPINFO *pExcepInfo, UINT *puArgErr){ return S_OK; };
};

CMy2 csMy2;
STDMETHODIMP CMy1::GetInterface(IMy2 **pVal)
{
    CMy2 *p = &csMy2;
    *pVal = (IMy2 *)&p;
    return S_OK;
}

Client Side:
========

    CoInitialize(NULL);
    IMy1 *pIMy1=NULL;
    HRESULT hr;
    hr=CoCreateInstance(CLSID_My1,NULL,CLSCTX_LOCAL_SERVER,IID_IMy1,
(void**)&pIMy1);
    if (SUCCEEDED(hr))
    {
        IMy2 *pIMy2 = NULL;
        hr = pIMy1->GetInterface(&pIMy2); <== Got
ERROR_NOACCESS
    }
    CoUninitialize();

idl
==
[
    object,
    uuid(F3045B8C-E474-4DFF-8AC6-90936FF3779E),
    dual,
    helpstring("IMy2 Interface"),
    pointer_default(unique)
]
interface IMy2 : IDispatch
{
};

[
    object,
    uuid(F3045B8C-E474-4DFF-8AC6-90936FF3779B),
    dual,
    helpstring("IMy1 Interface"),
    pointer_default(unique)
]
interface IMy1 : IDispatch
{
    [id(1), helpstring("method GetInterface")] HRESULT
GetInterface([out,retval] IMy2 **pVal);
};

[
    uuid(ED1706E6-25A8-4050-99A4-8349C9385CEC),
    version(1.0),
    helpstring("ComTest 1.0 Type Library")
]
library COMTESTLib
{
    importlib("stdole32.tlb");
    importlib("stdole2.tlb");

    [
        uuid(42829015-7E0E-4226-B6C0-1590DC89B3E9),
        helpstring("My1 Class")
    ]
    coclass My1
    {
        [default] interface IMy1;
    };
};

If any improper, please correct me.
Thank you.

Ceasar