Using-declaration or using-directive inside unnamed-namespace?

[Niels Dekker - no reply address]

We have some using-declarations and using-directives at file scope (in a CPP
file, right after the #include statements). Does it matter much if they are
places in an unnamed namespace instead? I mean, does it make any difference
(file scope versus unnamed-namespace)?

For example:

#include "my_things.h"
#include <memory>

namespace // unnamed
{
using ::std::tr1::shared_ptr;
using namespace my_things;
}

// Using shared_ptr and things from my_things here...


Kind regards,

Niels

 

[Niels Dekker - no reply address]

We have some using-declarations and using-directives at file scope

The using declarations and using-directives only have effect for this
particular translation unit. They don't create additional symbols
that might become visible from another module, if that's what you're
worrying about.

Thanks, Victor. So it doesn't really matter whether they are inside an
unnamed namespace or at file scope.

I thought so already, but I wanted to be sure

Kind regards,

Niels