LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME

C++

Language

Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

Localizations library

Locales and facets
locale
use_facet	has_facet
Character classification
isspace isblank (C++11) iscntrl isupper islower isalpha	isdigit ispunct isxdigit isalnum isprint isgraph
Conversions
toupper tolower	wstring_convert (C++11) wbuffer_convert (C++11)
Facet category base classes
ctype_base codecvt_base messages_base	time_base money_base
Facet categories
ctype ctype<char> codecvt collate messages time_get time_put	num_get num_put numpunct money_get money_put moneypunct
Locale-specific facets
ctype_byname codecvt_byname messages_byname collate_byname	time_get_byname time_put_byname numpunct_byname moneypunct_byname
Code conversion facets
codecvt_utf8 (C++11) codecvt_utf16 (C++11)	codecvt_utf8_utf16 (C++11) codecvt_mode (C++11)
C locale
setlocale localeconv lconv	LC_ALLLC_COLLATELC_CTYPELC_MONETARYLC_NUMERICLC_TIME

Defined in header <clocale>
#define LC_ALL /*implementation defined*/
#define LC_COLLATE /*implementation defined*/
#define LC_CTYPE /*implementation defined*/
#define LC_MONETARY /*implementation defined*/
#define LC_NUMERIC /*implementation defined*/
#define LC_TIME /*implementation defined*/

Each of the above macro constants expand to integer constant expressions with distinct values that are suitable for use as the first argument of std::setlocale.

Constant	Explanation
LC_ALL	selects the entire C locale
LC_COLLATE	selects the collation category of the C locale
LC_CTYPE	selects the character classification category of the C locale
LC_MONETARY	selects the monetary formatting category of the C locale
LC_NUMERIC	selects the numeric formatting category of the C locale
LC_TIME	selects the time formatting category of the C locale

Additional macro constants, with names that begin with LC_ followed by at least one uppercase letter, may be defined in <clocale>. For example, the POSIX specification requires LC_MESSAGES (which controls std::perror and std::strerror), ISO/IEC 30112:2014 (2014 draft) additionally defines LC_IDENTIFICATION, LC_XLITERATE, LC_NAME, LC_ADDRESS, LC_TELEPHONE, LC_PAPER, LC_MEASUREMENT, and LC_KEYBOARD, which are supported by the GNU C library (except for LC_XLITERATE)

Example

Run this code

#include <cstdio>
#include <clocale>
#include <ctime>
#include <cwchar>

int main()
{
    std::setlocale(LC_ALL, "en_US.UTF-8"); // the C locale will be the UTF-8 enabled English
    std::setlocale(LC_NUMERIC, "de_DE.UTF-8");   // decimal dot will be German
    std::setlocale(LC_TIME, "ja_JP.UTF-8");      // date/time formatting will be Japanese
    wchar_t str[100];
    std::time_t t = std::time(nullptr);
    std::wcsftime(str, 100, L"%A%c", std::localtime(&t));
    std::wprintf(L"Number:%.2f\nDate:%Ls\n", 3.14, str);
}

Output:

Number: 3,14
Date:  20111219 180440

See also

setlocale	gets and sets the current C locale (function)
locale	set of polymorphic facets that encapsulate cultural differences (class)