CORBA24 — Problem with valuetype parameter copying

Corba 2.3.1 section 5.2.4.3 states that valuetypes passed as parameters
are copied when passed into the receiving context. Is this also true
for valuetypes that are embedded in a contructed IDL type passed as a
parameter?

Example:

// IDL

valuetype V { };

struct S

;

interface I

;

When I::op is called are the valuetypes embedded in s1, s2, s3 and the
return value supposed to be copied when making a collocated call?

Example 2:

// IDL

interface J

;

If one of the any parameters to J::op contains a valuetype, must it be
copied before/after a collocated call? What if the any contains a
struct S instead?

It seems to me we need to revisit the valuetype copying issue. We have
three choices:

1. Valuetypes are not copied for collocated calls.
2. Only valuetypes as explicit parameters are copied for collocated
calls.
3. All valuetypes are copied no matter how deeply they are nested in
parameters.

Currently the specification is ambiguous as to whether the semantics are
supposed to be case 2 or 3. Case 3 is the only one that provides
guaranteed location transparency, but the cost to implement case 3 for
collocated calls far too high. It would effectively require the same
overhead as marshalling/unmarshalling for any operation that has a
valuetype embedded in a complex IDL type or any.

So, given that transparency for collocated calls cannot be maintained
without high overhead, should we completely remove the copying
requirement because transparency cannot be maintained, or should we just
document that case 2 is the accepted semantic?

resolved, see below