std::locale::id::id (3) - Linux Man Pages
Defined in header <locale>
id(const id&) = delete; (2)
1) default constructor: creates an object of type std::locale::id with implementation-specific content.
2) copy constructor is deleted; std::locale::id is not copyable.
Because locales and facets must be available for the IO stream objects with static storage duration, such as std::cout, typical implementations let implicit default constructor zero-initialize the contents of std::locale::id during static initialization (before constructors run for static objects), and when a facet is added to any locale for the first time, the locale completes initialization of the facet's id.