Concept-check bug ?

Jonathan Wakely cow@compsoc.man.ac.uk
Fri Jun 17 12:34:00 GMT 2005


On Fri, Jun 17, 2005 at 03:12:40PM +0300, Peter Dimov wrote:

> Jonathan Wakely wrote:
> >Hi y'all,
> >
> >   #define _GLIBCXX_CONCEPT_CHECKS
> >   #include <vector>
> >
> >   struct A {
> >       std::vector<A> v;
> >   };
> >
> >This produces concept-check errors because A is incomplete at the
> >point of declaring v.
> >
> >Is this code really illegal, or just a flaw in the concept-checks ?
> 
> It's illegal (17.4.3.6/2 last bullet), but useful.

Thanks, Peter (I should have known that).

Presumably the truly legal way to do it is with a (smart) pointer to the
vector type:

    struct A {
        std::tr1::shared_ptr<std::vector<A> > v;

        A() : v(new std::vector<A>) { }
    };

jon

-- 
"You're not drunk if you can lie on the floor without holding on."
	- Dean Martin



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