[omniORB] declaration bug affecting rethrowing of CORBA::Exception?

[Bruce Visscher]

Huw,

Huw Rogers wrote:
> 
> Hi,
> 
> This code fails to compile on gcc 2.96/Linux and
> CC 5.0/Solaris:
> 
> try {
> // some method invocation
> } catch (const CORBA::Exception &e) {
> // do something like print an error
> throw e;
> }
> 
> gcc reports:
> CORBA::Exception::Exception (const CORBA::Exception &)' is
> protected within this context
> 
> CC reports:
> Error: CORBA::Exception::Exception(const CORBA::Exception&) is not accessible from
> ...
> 
> This is due to _MSC_VER not being defined
> at line 826 of omniORB3/CORBA.h (comment
> at that line indicates that this problem was experienced
> with MSVC++), which declares the copy ctor
> of CORBA:Exception public.
> 
> This is probably a bug.

Actually, the error message is saving you from making a mistake.  What
you are attempting to do is to "slice" the exception object, which is
probably not what you want to do.  You should change your throw
statement to a rethrow (spelled "throw;", i.e., throw with no target
object) and I believe the errors will go away.  More importantly, you
will be rethrowing the original object (or a complete copy of it) rather
than just the CORBA::Exception base object which doesn't have as much
information about the error.

I think the decision to make the copy constructor protected to catch
mistakes like this shows good design forethought.

HTH,

Bruce
-- 

Bruce Visscher                                        visschb@rjrt.com

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