Creates an OLE embedding helper object using application-supplied code aggregated with pieces of the OLE default object handler. This helper object can be created and used in a specific context and role, as determined by the caller.
WINOLEAPI OleCreateEmbeddingHelper(
REFCLSID clsid, //Identifier of the class to be helped
LPUNKNOWN pUnkOuter, //Pointer to controlling IUnknown if
// aggregated; else NULL
DWORD flags, //Purpose for the helper
LPCLASSFACTORY pCF, //Pointer on the class object for the
// secondary object
REFIID riid, //Reference to the identifier of the
// interface desired by the caller
LPVOID * ppvObj //Address of output variable that receives
// the interface pointer requested in riid
);
This function supports the standard return values E_INVALIDARG, E_OUTOFMEMORY, and E_UNEXPECTED, as well as the following:
The OleCreateEmbeddingHelper function creates an object that supports the same interface implementations found in the default handler, but which has additional hooks that allow it to be used more generally than just as a handler object. The following two calls produce the same result:
OleCreateEmbeddingHelper(clsid, pUnkOuter, EMBDHLP_INPROC_HANDLER |
EMBDHLP_CREATENOW, NULL, iid, ppvObj)
OleCreateDefaultHandler(clsid, pUnkOuter, iid, ppvObj)
The embedding helper is aggregatable; pUnkOuter is the controlling IUnknown of the aggregate of which the embedding helper is to be a part. It is used to create a new instance of the OLE default handler, which can be used to support objects in various roles. The caller passes a pointer to its IClassFactory implementation to OleCreateEmbeddingHelper. This object and the default handler are then aggregated to create the new embedding helper object.
The OleCreateEmbeddingHelper function is usually used to support one of the following implementations:
CoRegisterClassObject(clsidMe, pUnkCfLocal, CLSCTX_LOCAL_SERVER,
REGCLS_MULTI_SEPARATE...)
CoRegisterClassObject(clsidMe, pUnkCfInProc, CLSCTX_INPROC_SERVER,
REGCLS_MULTI_SEPARATE...)
In these calls, you would pass along different class factory implementations to each of pUnkCfLocal and pUnkCfInProc. The class factory pointed to by pUnkCfLocal would be used to create objects that are to be embedded in a remote process, which is the normal case which uses a handler object associated with the client. However, when a server both creates an object and embeds it within itself, pUnkCfInProc points to a class object that can create an object that supports the handler interfaces. The local class is used to create the object and the in-process class creates the embedding helper, passing in the pointer to the first object's class factory in pCF.
The flags parameter indicates how the embedding helper is to be used and how and when the embedding helper is initialized. The values for flags are obtained by OR-ing together values from the following table:
| Values for flags Parameter | Purpose |
|---|---|
| EMBDHLP_INPROC_HANDLER | Creates an embedding helper that can be used with DLL object applications; specifically, the helper exposes the caching features of the default object handler. |
| EMBDHLP_INPROC_SERVER | Creates an embedding helper that is to be used as part of an in-process server. pCF cannot be NULL. |
| EMBDHLP_CREATENOW | Creates the secondary object using pCF immediately; if pCF is null, the standard proxy manager is used. |
| EMBDHLP_DELAYCREATE | Delays creation of the secondary object until it is needed (when the helper is put into the running state) to enhance speed and memory use. pCF must not be NULL. The EMBDHLP_INPROC_HANDLER flag cannot be used with this flag. |
Windows NT: Use version 3.1 or later.
Windows: Use Windows 95 or later.
Windows CE: Unsupported.
Header: Declared in ole2.h.
Import Library: Included as a resource in ole32.dll.