9 Declarations [dcl]

9.9 Namespaces [basic.namespace]

9.9.3 Namespace alias [namespace.alias]

A namespace-alias-definition declares an alternate name for a namespace according to the following grammar:

namespace-alias:
identifier

namespace-alias-definition:
namespace identifier = qualified-namespace-specifier ;

qualified-namespace-specifier:
nested-name-specifier

_{o p t}

namespace-name

The identifier in a namespace-alias-definition becomes a namespace-alias and denotes the namespace denoted by the qualified-namespace-specifier.

[Note 1:

When looking up a namespace-name in a namespace-alias-definition, only namespace names are considered, see [basic.lookup.udir].

— end note]