Re: [orbitcpp-list] passing a reference to another process

[Phil D. <ph...@us...>]

Hi Martin,

Sorry for the late reply - I've been a bit busy recently (and it took
me a couple of reads to understand this mail ;-)

Martin Schulze writes:
 > 
 > Hi,
 > 
 > I ran into some troubles implementing a signal-slot-technology
 > with CORBA-objects:
 > 
 > 
 > Given three processes pA, pB, pC.
 > Is it possible to pass a reference retrieved in process pC from
 > the IOR referring to an object in the address space of pB
 > to process pA directly ?
 > 

Yes, you can pass the object reference as an idl argument to a corba
method. You must ensure that you call the relevant reference
'_duplicate' function though. (This duplicates the object reference,
not the corba object implementation)

e.g. for function returning a reference to interface foo:

  return foo::_duplicate(myfooreference);


 > 
 > 
 > In details:
 > 
 > Let's say I have interfaces iA, iAA, iB, iBB.
 > class iA_impl contains a class iAA_impl (= oAA),
 > class iB_impl contains a calss iBB_impl (= oBB).
 > 
 > Now I have two processes running, pA and pB.
 > pA has an iA_impl on the heap (= oA), pB an iB_impl (= oB).
 > 

With you so far (I think).

 > A third process pC is created, retrieving refences to oA and oB
 > through their IORs. A function of iA is called, returning a
 > reference to oAA and a function of iB gives a reference to oBB.
 > Now a function of iAA is called, giving the REFERENCE to oBB
 > AS its ARGUMENT.

Yep - sounds okay. (must do your _duplicates though).

 > 
 > Another function of oAA is called. It implicitely calls a function
 > of oBB - so process pA uses the reference of oBB that was
 > retrieved in process pC.
 > 
 > => A SEGFAULT in pA occurs in the function _orb_get_connection
 > called by the skel of the very last function call mentioned obove.
 > => Bug in orbit or my design error ???
 > 
 >

Unlike EJB, CORBA doesn't have any rules govening callback functions
(recursive calls etc), so this should all work AFAIK. 

It's a little difficult to see what the problem could be without code
- could you send me a copy of your idl and impl C++ files?

Cheers,

Phil