std::locale

From Cppreference

An object of class std::locale is an indexed set of reference-counted pointers to facets. Each stream object of the C++ input/output library is associated with an std::locale and uses its facets for parsing and formatting of all data. In addition, a locale object is associated with each basic_regex object. Locale objects can also be used as predicates that perform string collation with the standard containers and algorithms and can be accessed directly to obtain or modify the facets they hold.

Each locale constructed in a C++ program holds at least the following standard facets: std::collate<char>, std::collate<wchar_t>, std::ctype<char>, std::ctype<wchar_t>, std::codecvt<char,char,mbstate_t>, std::codecvt<char16_t,char,mbstate_t>, std::codecvt<char32_t,char,mbstate_t>, std::codecvt<wchar_t,char,mbstate_t>, std::moneypunct<char>, std::moneypunct<wchar_t>, std::moneypunct<char,true>, std::moneypunct<wchar_t,true>, std::money_get<char>, std::money_get<wchar_t>, std::money_put<char>, std::money_put<wchar_t>, std::numpunct<char>, std::numpunct<wchar_t>, std::num_get<char>, std::num_get<wchar_t>, std::num_put<char>, std::num_put<wchar_t>, std::time_get<char>, std::time_get<wchar_t>, std::time_put<char>, std::time_put<wchar_t>, std::messages<char>, std::messages<wchar_t>, but a program may define additional specializations or completely new facets and add them to any existing locale object.

[edit] Member types

[edit] Member objects

[edit] Member functions

[edit] Example

Demonstrates the typical prologue of a locale-sensitive program (cross-platform)

#include <iostream>
#include <locale>
int main()
{
    std::wcout << "User-preferred locale setting is " << std::locale("").name().c_str() << '\n';
    // on startup, the global locale is the "C" locale
    std::wcout << 1000.01 << '\n';
    // replace the C++ global locale as well as the C locale with the user-preferred locale
    std::locale::global(std::locale("") );
    // use the new global locale for future wide character output
    std::wcout.imbue(std::locale());
    // output the same number again
    std::wcout << 1000.01 << '\n';
}

Output:

User-preferred locale setting is en_US.UTF8
1000.01
1,000.01

[edit] See also