The ICreateTypeInfo2 interface derives from ICreateTypeInfo, and adds methods for deleting items that have been added through ICreateTypeInfo.
The ICreateTypeInfo::LayOut method provides a way for the creator of the type information to check for any errors. A call to QueryInterface() can be made to the ICreateTypeInfo instance at any time for its ITypeInfo interface. Calling any of the methods in the ITypeInfo interface that require layout information lays out the type information automatically.
interface ICreateTypeInfo2 : ICreateTypeInfo