NAME

std::locale::id - std::locale::id

Synopsis

Defined in header <locale>
class locale::id;

The class std::locale::id provides implementation-specific identification of a
locale facet. Each class derived from std::locale::facet must have a public static
member named id of type std::locale::id and each std::locale object maintains a list
of facets it implements, indexed by their ids.

Facets with the same id belong to the same facet category and replace each other
when added to a locale object.

Member functions

constructor constructs a new id
(public member function)
operator= copy assignment operator is deleted
(public member function)

Example

The following example shows how to construct a minimal custom facet.

// Run this code

#include <iostream>
#include <locale>

struct myfacet : std::locale::facet
{
myfacet(std::size_t refs = 0) : facet(refs) {}
static std::locale::id id;
};

std::locale::id myfacet::id;

int main()
{
std::locale myloc(std::locale(), new myfacet);
std::cout << "has_facet<myfacet>(myloc) returns " << std::boolalpha
<< std::has_facet<myfacet>(myloc) << '\n';
}

Output:

has_facet<myfacet>(myloc) returns true

See also

the base class for all facet categories: each facet of any category is derived
facet from this type
(class)