Re: [boost] sizeof_array?

From: Daniel Frey (daniel.frey_at_[hidden])
Date: 2002-06-25 07:35:59

Kostya Altukhov wrote:
> 
> Daniel Frey wrote:
> 
> >template< typename T, size_t N >
> >const char (&sizer(const T(&)[N]))[N];
> >
> You need to remove 'const' here. Then it obviously will not
> work for types, but the following snippet works fine with
> gcc 3.0.2, gcc 2.95.2, and online comeau:

Meanwhile I was pointed to Dietmar's header array_traits.hpp and
personally, I'm quiet satified with the implementation we have now -
although it requires a bit more typing, it seems more natural to me
(given __typeof is available). But without typeof, we could add

namespace boost {
   namespace array {
      // Declaration only
      template< typename T, size_t N > const char
(&static_size(T(&)[N]))[N];
   }
}

and use

   V2 = sizeof( boost::array::static_size( x ) )

but leave V1 as it is. Probably the name should be better...
Both can live side by side, although I'd prefer to have 'typeof'.

> For typedefs such as "typedef int X[42];", a non-portable line that
> works with mentioned compilers is "V1 = sizeof( sizer(*(X*)1 ))",
> though I would not advise anybody to use that :-)

We better forget that, right? ;)

Regards, Daniel

--
Daniel Frey
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