Re: const-correct smartpointers

[Bowie Owens <bowie owens csiro au>]

Hi Murray,

Unfortunately, your changes don't work for me. When I have const _var 
object and try and cast it to a _ptr I get errors.

I am not familiar with MICO, but omniORB has a simple approach to avoid 
the warnings. In omniORB, rather than provide two operators (and thus 
cause GCC to complain) they only provide one. The const one. Also, 
rather than return a reference to a pointer, they just copy it. The code 
before your changes was:

       operator O_ptr &() {
               return m_objectref;
       }
                                                                              
       operator O_ptr const &() const {
               return m_objectref;
       }

To follow the omni approach the two operators would then become:

       operator O_ptr () const {
               return m_objectref;
       }

This allows const correct behaviour. It avoids the warnings. Plus it 
gets rid of that weird first operator which lets you modify m_objectref 
without respecting memory management.

The reason I didn't suggest this earlier is because the C++ mapping spec 
I got of the OMG website has both the above operators in its sample code 
(section 1 page 13). Also TAO has both operators in its implementation. 
I thought it might have something to do with the standard (I don't have 
a good reference). But if omni doesn't have the non-const operator maybe 
it should be dropped from orbitcpp.

What do you think?


Murray Cumming Comneon com wrote:

> I applied a temporary, and maybe useless, fix to ObjectPtr_var<>, to avoid
> the masses of warnings:
>
> http://cvs.gnome.org/lxr/source/orbitcpp/orbitcpp/orb-cpp/smartpointers/obje
> ctptr_var.h#36
> http://cvs.gnome.org/lxr/source/orbitcpp/orbitcpp/orb-cpp/smartpointers/obje
> ctptr_var.h#93
>
> To have proper const-correctness I think we need to avoid specifying the
> pointer type to the template. See the comments for more clues. The
> equivalent in mico doesn't seem to need to do this.
>
> Murray Cumming
> murrayc usa net
> www.murrayc.com 
> _______________________________________________
> orbitcpp-list mailing list
> orbitcpp-list gnome org
> http://mail.gnome.org/mailman/listinfo/orbitcpp-list
>  


--
Bowie Owens

CSIRO Mathematical & Information Sciences
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email  : Bowie Owens csiro au