[facet.numpunct.members]
28 Text processing library [text]
28.3 Localization library [localization]
28.3.4 Standard locale categories [locale.categories]
28.3.4.4 The numeric punctuation facet [facet.numpunct]
28.3.4.4.1 Class template numpunct [locale.numpunct]
28.3.4.4.1.2 Members [facet.numpunct.members]
char_type decimal_point() const;
char_type thousands_sep() const;
string grouping() const;
string_type truename() const;
string_type falsename() const;