catalog open(const string& name, const locale& loc) const;
string_type get(catalog cat, int set, int msgid, const string_type& dfault) const;
void close(catalog cat) const;
catalog do_open(const string& name, const locale& loc) const;
string_type do_get(catalog cat, int set, int msgid, const string_type& dfault) const;
void do_close(catalog cat) const;