Re: [boost] Unnamed namespaces?

From: Giovanni Piero Deretta (gpderetta_at_[hidden])
Date: 2007-06-15 09:14:54

On 6/15/07, David Abrahams <dave_at_[hidden]> wrote:
> [...]
> I would put the reference itself in an unnamed namespace, and I'm pretty
> sure that handles it.  As long as the reference refers to something
> not in an unnamed namespace:
>
>    template<typename T> struct static_const
>    {
>      static T const value;
>    };
>
>    template<typename T>
>    T const static_const<T>::value = {};
>
>    struct placeholder {};
>
>    namespace // <<============== HERE
>    {
>      placeholder const &_1 = static_const<placeholder>::value;
>    }
>
>    template<class T> void foo(T const &)
>    {
>      // use _1 here. OK, _1 refers to the same object
>      // in all translation units.  It doesn't matter that the
>      // reference is has a different identity; the object is
>      // the same: static_const<placeholder>::value
>    }
>
>

Instead of using a class statics, I've been using function static locals,
the same trick used by the BOOST_PARAMETER_KEYWORD macro.
What are the advantages and the disadvantages of the two aproach?

Consider that I'm using the trick to name stateless function objects
in header files
These function objects sometime have a constructors, but I could
easily make all of them POD if this would force the compiler to use
static initialization.

Anyways, why is it a necessity to have those objects statically
initialized even if they are stateless?

gpd