Developing mixed-language code with fortran-dev and g++

[Gabriel Dos Reis]

On Thu, Nov 26, 2009 at 5:38 AM, Paul Richard Thomas
<paul.richard.thomas@gmail.com> wrote:
> Dear Nick,
>
>> If you find any comprehensible documentation on C++ underlying concepts,
>> and implementation assumptions, PLEASE tell me.  I can tell you from
>> certain knowledge that they have to be reverse engineered from between
>> the lines of the standard.  Even Bjarne's books are short on such detail,
>> which isn't unreasonable, but it's a specialist need.
>
> Thus challenged, I thought that I would give it a try!
>
> I have found some references where I recognize what is described and,
> I am glad to say, in the fortran-dev version of OOP, Janus and I have
> even evolved to something fairly close to the C++ industry standard
> ABI.  I give a few references below.
>
> Sod's Law would have us inverting the standard order of vptr and the
> content of the base object; and so it has turned out!  Also, our base
> object content is pointed to, either in the form of a pointer or an
> allocatable component.
>
> The vtable implementation is also somewhat different but we could
> converge; g++ has a pointer to unknown_function () and, as far as I
> can tell, is padded out with nulls between the procedure pointers.  We
> also have no need for the four default methods for C++ and so,
> obviously, they have not been implemented.  In addition there is other
> base information in the C++ vtable that we should review.  Amongst
> other things, we are still relying on a hash of the dynamic type name
> and module to identify the type at runtime.  We need to have a name
> register and to use pointers to the entries or unique keys.
>
> Finally, we should understand how g++ implements the initialization of
> its vtables; otherwise we have a fairly complete toolkit to prepare
> any implementation that we care to.
>
> Janus and I can go a little bit further before we require some
> decision making process on the details of OOP in gfortran.
>
> Cheers
>
> Paul
>
> In no particular order:
> http://en.wikipedia.org/wiki/Virtual_method_table
> http://www.codesourcery.com/public/cxx-abi/cxx-vtable-ex.html
> http://www.cse.wustl.edu/~mdeters/seminar/fall2005/mi.html#virtual
> http://www.codesourcery.com/public/cxx-abi/abi.html#acknowledgements

You can add "The Annotated C++ Reference Manual", the base document
for the C++98 standard; and "The C++ Object Model".

-- Gaby


>