Re: [boost] [mpl] Patch for mpl::aux::msvc_eti_base for MSVC7.0

From: Aleksey Gurtovoy (agurtovoy_at_[hidden])
Date: 2003-03-09 22:12:47

Andreas Huber wrote:
> Hi Aleksey

Hi Andreas,

>
> Sometimes I have to pass an abstract class to mpl::aux::msvc_eti_base.
> On MSVC7.0 the compiler complains with the following error:
>
> d:\Data\boostCvsRoot\boost\boost\mpl\aux_\is_msvc_eti_arg.hpp(48) :
> error C2259: 'boost::mpl::inherit2<T1,T2>' : cannot instantiate
> abstract class ...
>
> The following patch to the current CVS version seems to fix this:
>
> RCS file: /cvsroot/boost/boost/boost/mpl/aux_/is_msvc_eti_arg.hpp,v
> retrieving revision 1.1
> diff -r1.1 is_msvc_eti_arg.hpp
> 48c48
> < static T get();
> ---
> > static const T & get();
>
> Since T is never cv-qualified or a reference, this should work under all
> circumstances.

Uhmm, actually 'is_msvc_eti_arg' can be used in other contexts, including
the ones where T can be everything, and in particular a reference; so, in
the long run, we'll have to do something a little bit more sophisticated to
fix it, but for now 'T&' will do. Fixed in the CVS.

> P.S. Just to make sure you've seen it:
>
> http://lists.boost.org/MailArchives/boost/msg44601.php
>
> It's definitely low prio because it's a *warning* appearing only on
MSVC7.1.

There were two issues there - 'distance' returning an unsigned type, and,
as you've pointed out, the 'advance' implementation itself. Both fixed in
the
CVS now.

Thanks for the report,
Aleksey