Cpp Coding Standards/ENC/Internal
From Apache OpenOffice Wiki
Giving out handles to your class internals is just another way to make internals public, and makes keeping class invariants hard to impossible (see ENC:PrivData).
Exception: Sometimes member data of a class are just aggregated to it, but the state of this one member is not part of the class's invariants. In such case a get-/set-access to this data may be okay.
