[locale.convenience]

# 28 Text processing library [[text]](./#text)

## 28.3 Localization library [[localization]](localization#locale.convenience)

### 28.3.3 Locales [[locales]](locales#locale.convenience)

#### 28.3.3.3 Convenience interfaces [locale.convenience]

#### [28.3.3.3.1](#classification) Character classification [[classification]](classification)

[🔗](#lib:isspace)

`template<class charT> bool isspace (charT c, const locale& loc);
template<class charT> bool isprint (charT c, const locale& loc);
template<class charT> bool iscntrl (charT c, const locale& loc);
template<class charT> bool isupper (charT c, const locale& loc);
template<class charT> bool islower (charT c, const locale& loc);
template<class charT> bool isalpha (charT c, const locale& loc);
template<class charT> bool isdigit (charT c, const locale& loc);
template<class charT> bool ispunct (charT c, const locale& loc);
template<class charT> bool isxdigit(charT c, const locale& loc);
template<class charT> bool isalnum (charT c, const locale& loc);
template<class charT> bool isgraph (charT c, const locale& loc);
template<class charT> bool isblank (charT c, const locale& loc);
`

[1](#classification-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/text.tex#L1240)

Each of these functions is*F* returns the result of the expression:use_facet<ctype<charT>>(loc).is(ctype_base::*F*, c) where *F* is the ctype_base​::​mask value
corresponding to that function ([[category.ctype]](category.ctype "28.3.4.2 The ctype category"))[.](#classification-1.sentence-1)[216](#footnote-216 "When used in a loop, it is faster to cache the ctype&lt;> facet and use it directly, or use the vector form of ctype&lt;>​::​is.")

[216)](#footnote-216)[216)](#footnoteref-216)

When used in a loop,
it is faster to cache the ctype<> facet and use it directly, or
use the vector form of ctype<>​::​is[.](#footnote-216.sentence-1)

#### [28.3.3.3.2](#conversions.character) Character conversions [[conversions.character]](conversions.character)

[🔗](#lib:toupper)

`template<class charT> charT toupper(charT c, const locale& loc);
`

[1](#conversions.character-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/text.tex#L1262)

*Returns*: use_facet<ctype<charT>>(loc).toupper(c)[.](#conversions.character-1.sentence-1)

[🔗](#lib:tolower)

`template<class charT> charT tolower(charT c, const locale& loc);
`

[2](#conversions.character-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/text.tex#L1273)

*Returns*: use_facet<ctype<charT>>(loc).tolower(c)[.](#conversions.character-2.sentence-1)