[v3] PATCH: PR 20599 (variadic templates, take two) (4/4)

[Peter Dimov]

Gennaro Prota wrote:
> On Wed, 20 Sep 2006 20:15:29 +0200, Paolo Carlini <pcarlini@suse.de>
> wrote:
> 
>> Douglas Gregor wrote:
>> 
>>> This is part 4 of 4. It contains changes to libstdc++'s TR1
>>> implementation to make full use of variadic templates, eliminating
>>> all of the preprocessor metaprogramming that we're using now.
>> 
>> +  // Define a large number of placeholders. There is no way to
>> +  // simplify this with variadic templates, because we're
>> introducing +  // unique names for each.
>> +  namespace placeholders { namespace {
>> +    _Placeholder<1> _1;
>> +    _Placeholder<2> _2;
>> +    _Placeholder<3> _3;
>> +    ...
>> +  } }
> 
> Hi,
> 
> is this in an included file? You don't want to open an unnamed
> namespace there.

Yep, TR1/WP calls for

namespace placeholders
{
    extern _Placeholder<1> _1;
    // ...
}