[namespace.unnamed]

# 9 Declarations [[dcl]](./#dcl)

## 9.9 Namespaces [[basic.namespace]](basic.namespace#namespace.unnamed)

### 9.9.2 Namespace definition [[namespace.def]](namespace.def#namespace.unnamed)

#### 9.9.2.2 Unnamed namespaces [namespace.unnamed]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L8373)

An [*unnamed-namespace-definition*](namespace.def.general#nt:unnamed-namespace-definition "9.9.2.1 General [namespace.def.general]") behaves as if it were
replaced by

inlineopt namespace *unique* { /* empty body */ }  
using namespace *unique* ;  
namespace *unique* { [*namespace-body*](namespace.def.general#nt:namespace-body "9.9.2.1 General [namespace.def.general]") }

whereinline appears if and only if it appears in the[*unnamed-namespace-definition*](namespace.def.general#nt:unnamed-namespace-definition "9.9.2.1 General [namespace.def.general]") and all occurrences of *unique* in a translation unit are replaced by
the same identifier, and this identifier differs from all other
identifiers in the program[.](#1.sentence-1)

The optional [*attribute-specifier-seq*](dcl.attr.grammar#nt:attribute-specifier-seq "9.13.1 Attribute syntax and semantics [dcl.attr.grammar]") in the [*unnamed-namespace-definition*](namespace.def.general#nt:unnamed-namespace-definition "9.9.2.1 General [namespace.def.general]") appertains to *unique*[.](#1.sentence-2)

[*Example [1](#example-1)*: namespace { int i; } // *unique*​::​ivoid f() { i++; } // *unique*​::​i++namespace A {namespace {int i; // A​::​*unique*​::​iint j; // A​::​*unique*​::​j}void g() { i++; } // A​::​*unique*​::​i++}using namespace A;void h() { i++; // error: *unique*​::​i or A​::​*unique*​::​i A::i++; // A​::​*unique*​::​i j++; // A​::​*unique*​::​j} — *end example*]