From cppreference.com
Namespace aliases allow the programmer to define an alternate name for a namespace.
They are commonly used as a convenient shortcut for long or deeply-nested namespaces.
Syntax
namespacealias_name = ns_name;(1) namespacealias_name = ::ns_name;(2) namespacealias_name = nested_name::ns_name;(3) namespacealias_name = splice-specifier;(4) (since C++26)alias_name- an identifier ns_name- a (possibly
) identifier that names a namespace or namespace alias splice-specifier- a
that designates a namespace that is not the global namespace Explanation
The new alias alias_name provides an alternate method of accessing ns_name or the namespace designated by splice-specifier(since C++26).
alias_name must be a name not previously used. alias_name is valid for the duration of the scope in which it is introduced.
Keywords
Example
Run this code
#include<iostream>namespacefoo{namespacebar{namespacebaz{intqux=42;}}}namespacefbz=foo::bar::baz;intmain(){std::cout<<fbz::qux<<'\n';}Output:
42 See also