When creating object identifiers for your information model, use the Guidgen.exe program to create an unused GUID, and use the DEFINE_OBJID(name, uniqifier, guid) macro to create the object identifiers. Given a GUID and a unique number for an object, the macro will equate the symbolic name to the value for the object identifier. Use the DEFINE_OBJID macro (which is provided for both Visual C++ and Visual Basic® programmers) to avoid incompatibility problems later.