[pooma-dev] domain architecture diagram

[Mark Mitchell]

 I don't know if
> this issue of the empty base class is important anymore
> with current C++ compilers.

This was the only part of this discussion I was smart enough to
understand, so I decided to reply to it. :-)

In G++ 3.0, there is no empty base class penalty.  The same will
be true for any IA64 C++ ABI compliant compiler.  Modern versions
of the EDG front end (used in KCC, the Intel compiler, the SGI
compiler, the DEC/Compaq compiler, and elsewhere) are capable of
avoiding the penalty.  However, I do now know if the vendors were
willing to turn on this feature, since it will break compatibility
with previous versions of their compilers.  And, I do not know
whether VC++ is capable of avoiding the penalty.

Irrelevant compilers for computers named after fruit are mentioned
only because I know that the mere presence of this sentence will
get people's adrenalin pumping in New Mexico. :-)  Seriously, I
know nothing of whether Metrowerks can do this or not.

It would be great if someone could try out:

 struct S { };
 struct T : public S { char c; };

 int main () { return sizeof (T); }

with KCC.  If things are good, the program will return 1; if bad,
some greater value.

-- 
Mark Mitchell                mark at codesourcery.com
CodeSourcery, LLC            http://www.codesourcery.com