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How do I use CoGetClassObject?

Posted on 1997-03-26
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Last Modified: 2013-11-20
I am trying to obtain an interface to an Automation Server which resides in a separate executable on the same machine (for example, Word (it's not word, but its the same type of server)).

I am successful at getting an interface and can then call methods with the IDispatch::Invoke method, however it starts a new instance of the EXECUTABLE each time I use CoGetClassObject (once per program run), even if the app is running already.

The SDK says it will first look for the server, and only create one when it is not available.  

This is all done in C++ (MSVC 4.2).  If I do the same thing in vb (dim object, etc.) it uses the instance of my server already running).    Here is a snipet of code:

LPCLASSFACTORY pIClassFactory;

   hr = CoGetClassObject( Clsid,
                          CLSCTX_INPROC_SERVER,
                          NULL,
                          IID_IClassFactory,
                          (LPVOID *)&pIClassFactory );

   if (SUCCEEDED(hr))
      {
      LPUNKNOWN   pUnk=NULL;

      pIClassFactory->CreateInstance(pUnk, IID_IDispatch, (LPVOID *)&m_pDispatch);
      pIClassFactory->Release();

      return TRUE;
      }

return FALSE;  // (failture)
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Question by:tdietz
1 Comment
 
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sapek earned 50 total points
ID: 1300700
I don't that think using CoGetClassObject followed by IClassFactory::CreateInstance is different then calling CoCreateInstance (as I know CoCreateInstance internaly just does call CoGetClassObject and IClassFactory::CreateInstance). So you should not expect that a running instance of a server will be used.
I am not but I think that you should use ROT (running object table) to get an instance of a running server. You can access it through GetRunningObjectTable.

Adam

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