CORBA23 — Null Value semantics under specified

he description of null value semantics (in ptc/99-03-07) is insufficient to ensure an adequate mapping to an
implementation language. Issues that should be specified include: - Creation. How are null values created? Are all declared (but
uninitialized) values born null? Is this a language mapping requirement or allowance? - Invocation. Presumably invoking an
operation ON a null value should result in an exception. But, what exception? Shouldn't the exception be specified for application
portability? - Passing. Presumably, it is allowable to provide a null value as the actual parameter for a non member operation (i.e.,
not on itself). True? - Typing: are null values typed, untyped, or is this governed by the language mapping? - Substitutability (see
"typing" above): – Presumably: a null value may be successfully widened to a null value of an ancestor stateful value type. True?
– Can a null value be successfully widened to a (null) supporting concrete interface? (Can a null value be activated as a servant?)
– Can a null value be successfully widened to a (null) supporting abstract interface? – Can a null value be successfully widened
to a (null) ancestor abstract value type? The only mentions of null values currently are: - the bullet in 5.2 - 5.2.4.2

close issue, no change