Question

I was looking over section 7.3.1.1 in the C++03 standard expecting to find some description of the access rules for items defined in an unnamed namespace.

The rules seem to be a little different for unnamed namespaces, since you cannot fully qualify access to items in one. I know that at least within the same translation unit, one can access items in an unnamed namespace as if they were not in a namespace. For example:

namespace {
  int foo;
}

void something()
{
  foo = 4;
}

If the namespace had a name, you could not do this. So, where are the rules defined in the standard for these exceptional rules that apply to unnamed namespaces?

Answer 1

An anonymous namespace is basically treated as:

namespace unique_per_TU
{
    // Stuff
}
using namespace unique_per_TU;

I’ll try to find the reference here in a minute.

EDIT:

It appears you already found it in 7.3.1.1/1

An unnamed namespace definition behaves as if it were replaced by

namespace unique { /* empty body */ }
using namespace unique;
namespace unique { namespacebody }

where all occurrences of unique in
a translation unit are replaced by the same identifier and this
identifier differs from all other identifiers in the entire program.

The “fake” using already brings the namespace members into the global namespace as you discovered.