/RTTI
       /RTTI (D)
       /NORTTI (Alpha only)

    Enables or disables support for RTTI (runtime type
    identification) features: dynamic_cast and typeid. Disabling
    runtime type identification can also save space in your object
    file because static information to describe polymorphic C++
    types is not generated. The default is to enable runtime type
    information features and generate static information in the
    object file. The /RTTI qualifier defines the macro __RTTI.

    Note that specifying /NORTTI does not disable exception handling.