You can use this macro to prevent an interface from being used in a particular case. For example, you can insert this macro into your COM map right before COM_INTERFACE_ENTRY_AGGREGATE_BLIND to prevent a query for the interface from being forwarded to the aggregate's inner unknown.
The interface IID will be constructed by appending x to IID_. For example, if x is IPersistStorage, the IID will be IID_IPersistStorage.
See COM_INTERFACE_ENTRY Macros for remarks about COM map entries.