LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME

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 .

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

#include <clocale>
#include <cstdio>
#include <ctime>
#include <cwchar>
 
int main()
{
    // the C locale will be the UTF-8 enabled English:
    std::setlocale(LC_ALL, "en_US.UTF-8");
 
    // decimal dot will be German:
    std::setlocale(LC_NUMERIC, "de_DE.UTF-8");
 
    // date/time formatting will be Japanese:
    std::setlocale(LC_TIME, "ja_JP.UTF-8");
 
    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);
}

Number: 3,14
Date: 日曜日 2022年11月06日 17時55分10秒

See also