Obtain an Interface Pointer Through a Co-creatable Co-class

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Creating a co-creatable class involves calling the CoCreateInstance function exposed by the COM library. A successful call to this function returns a pointer to the default interface of the co-class. Before calling CoCreateInstance, make sure that the COM library is properly initialized.

In Unified Communications Client API, UccPlatform is a co-creatable co-class and is used to obtain the IUccPlatform interface pointer. The following example is a code snippet drawn from an MFC sample application (installed as part of Unified Communications Client API).

// Initialize the COM library
HRESULT hr = CoInitialize(0);
if (FAILED(hr))
    // CoInitialize failed
return hr;

// Obtain a pointer to the IUccPlatform interface 
// by way of the cocreatable UccPlatform class.
CComPtr<IUccPlatform>  pIUccPlatform;
hr = CoCreateInstance(
        __uuidof(UccPlatform),
        NULL,
        CLSCTX_INPROC_SERVER,
        __uuidof(IUccPlatform),
        (LPVOID *)&pIUccPlatform
    );
if (FAILED(hr))
return hr;

CComBSTR bstrAppName = L"UccApiSampleApp";
hr = pIUccPlatform->Initialize( bstrAppName);
if (FAILED(hr))
    return false;

In MFC, the CComPtr<T> template class encapsulates a pointer (T*) to the type T. Therefore, in the previous code snippet, CComPtr<IUccPlatform> is the smart pointer version of IUccPlatform*.

See Also

Concepts

Obtaining Unified Communications Client API Interface Pointers
Call QueryInterface on an Existing Interface Pointer
Use a Factory Object to Obtain an Interface Pointer