[C++-sig] Re: Pyste suggestion: handling void * arguments

David Abrahams dave at boost-consulting.com
Sun Nov 2 01:16:18 CET 2003


"Niall Douglas" <s_sourceforge at nedprod.com> writes:

> On 31 Oct 2003 at 20:21, David Abrahams wrote:
>
>> >> I don't know, "undefined behaviour" is never good. Dave, what's
>> >> your opinion on this?
>> >
>> > It's no more undefined than the is_polymorphic trick in type_traits.
>> 
>> There is absolutely no undefined behavior in is_polymorphic
>
> Where in the C++ standard does it state that a class with a virtual 
> function table shall be bigger than one without?
>
> While the chances are that the above will remain true, it can't be 
> guaranteed and thus is strictly speaking undefined behaviour.

No, it's unspecified behavior.  Big difference.  Check your standard.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com





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