Gets the CLSID of a document type.
HRESULT GetCLSID( CLSID *pClsid );
[out] Pointer to the CLSID from the registry for the document type. This is used for items with special filter associations to indicate the appropriate filter to use for that embedded document.
If successful, returns S_OK, otherwise, it returns an error value. For a list of error messages returned by Enterprise Search in Microsoft Office SharePoint Server 2007, see Protocol Handler Error Messages.
If you do not provide an implementation for this method or the GetDocFormat method, the Filter Daemon makes the association between the item's file name extension and the Multipurpose Internet Mail Extensions (MIME) type.
Implement this method when the extensions you are handling might have a different association from what is indicated by the file name extension or content type. For example if ".doc" items in your content source are not associated with Microsoft Office Word files, this method should return the CLSID for the appropriate content type.