C++ In a Nutshell

<locale>

The <locale> header declares class and function templates for internationalization and localization. It supports conversion between narrow and wide character sets, character classification and collation, formatting and parsing numbers, currency, dates and times, and retrieving messages. For example, every I/O stream has a locale, which it uses to parse formatted input or to format output.

A locale is an embodiment of a set of cultural conventions, including information about the native character set, how dates are formatted, which symbol to use for currency, and so on. Each set of related attributes is called a facet, which are grouped into categories.

The categories are fixed and defined by the standard (see Table 13-20, under locale::category, for a complete list), and each category has several predefined facets. For example, one of the facets in the time category is time_get<charT, InputIter>, which specifies rules for parsing a time string. You can define additional facets; see the description of the locale::facet class in this section for details.

Many of the facets come in two flavors: plain and named. The plain versions implement default behavior, and the named versions implement the behavior for a named locale. See the locale class later in this section for a discussion of locale names.

When a program starts, the global locale is initialized to the "C" locale, and the standard I/O streams use this locale for character conversions and formatting. A program can change ...