CoCreateInstance(CLSID_StdGlobalInterfaceTable, NULL,
CLSCTX_INPROC_SERVER, IID_IGlobalInterfaceTable, (void **)&gpGIT) ;
        CoCreateInstance(CLSID_RemoteTime, NULL, CLSCTX_INPROC_SERVER,
IID_IRemoteTime, (void **)&m_pTimer) ;
        gpGIT->RegisterInterfaceInGlobal((IUnknown *) m_pTimer,
CLSID_RemoteTime, &pdwCookie);
        IRemoteTime* pInterface;
        gpGIT->GetInterfaceFromGlobal( pdwCookie, CLSID_RemoteTime,
reinterpret_cast<void**>(&pInterface) );

I can use "m_pTimer" to call methods of the COM server. But in the
above sample, "pInterface" is always 0.

Any one what's wrong?

Thanks.

1. Based on my experience and research, I found that the problem is caused
by call the RegisterInterfaceInGlobal() function with an inappropriate
parameter value.

gpGIT->RegisterInterfaceInGlobal((IUnknown *) m_pTimer,CLSID_RemoteTime,
&pdwCookie);

As in the above code, the second parameter should be of the IID of the
interface instead of class id(CLSID_RemoteTime). So as in this case, we can
change the code as the following:

gpGIT->RegisterInterfaceInGlobal((IUnknown *) m_pTimer, IID_IRemoteTime,
&pdwCookie);

2. It's the same with the GetInterfaceFromGlobal method.

3. I'd like to recommend the following articles for your further reference:
http://msdn.microsoft.com/library/en-us/com/cmi_d2l_77e4.asp
http://msdn.microsoft.com/library/en-us/com/cmi_d2l_7lt8.asp

Hope this helps!

Regards,
HuangTM

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