template <class Facet> const Facet& use_facet(const locale& loc);
Requires:
Facet
is a facet class whose definition contains the public static member
id
as defined in
[locale.facet]. Returns:
A reference to the corresponding facet of
loc, if present
. Throws:
bad_cast
if
has_facet<Facet>(loc)
is
false. Remarks:
The reference returned remains valid at least as long as any copy of
loc exists
. template <class Facet> bool has_facet(const locale& loc) noexcept;
Returns:
true if the facet requested is present in
loc; otherwise
false.