TITLE: anonymous namespaces

PROBLEM: jazzbeau@netcom.com (Steve Barnette)

Given the following code:

   static int i;

   namespace {
	int j;
    }
    int main() {
	::i = 0;
	::j = 0;	// error?
	return 0;
    }

Should ::j allow access to the integer defined in the anonymous namespace
as does the classic static definition?


RESPONSE: clamage@Eng.Sun.COM (Steve Clamage), 27 Oct 95

An unnamed namespace definition acts as if it were followed by a
using-directive for that (unnameable) namespace. The names declared
in that namespace are thus brought into the enclosing scope. In
your example, 'j' is brought into global scope. (Reference: WP
section 7.3.1.1, 7.3.4)

The unary '::' restricts name lookup to those names declared at global
scope, or visible in global scope due to a using-declaration. (WP 3.4.2)

Your example of "::j" therefore is valid and refers to the "j" in the
unnamed namespace.

Unnamed namespaces at global scope act much like "static" declarations,
but are more flexible. You can nest unnamed namespaces in other
namespaces, for example. The use of 'static' inside a namespace
is deprecated.