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# std::locale::locale

From cppreference.com
< cpp‎ | locale‎ | locale

Defined in header `<locale>` |  |
locale(); | (1) |
locale( const locale& other ); | (2) |
explicit locale( const char* std_name ); | (3) |
explicit locale( const std::string& std_name ); | (4) |
locale( const locale& other, const char* std_name, category cat ); | (5) |
locale( const locale& other, const std::string& std_name, category cat ); | (6) |
template< class Facet > locale( const locale& other, Facet* f ); | (7) |
locale( const locale& other, const locale& one, category cat ); | (8) |

Contstructs a new locale object.

1) Default constructor. Constructs a copy of the global C++ locale, which is the locale most recently used as the argument to std::locale::global or a copy of std::locale::classic if no call to std::locale::global has been made.
2) Copy constructor. Constructs a copy of `other`.
3-4) Constructs a copy of the system locale with specified `std_name` (such as "C", or "POSIX", or "en_US.UTF-8", or "English_US.1251"), if such locale is supported by the operating system. The locale constructed in this manner has a name.
5-6) Constructs a copy of `other` except for all the facets identified by the `cat` argument, which are copied from the system locale identified by its `std_name`. The locale constructed in this manner has the same name as `other`.
7) Constructs a copy of `other` except for the facet of type `Facet` (typically deduced from the type of the argument) which is installed from the argument `facet`. If `facet` is NULL, the constructed locale is a full copy of `other`. The locale constructed in this manner has no name.
8) Constructs a copy of `other` except for all the facets identified by the `cat` argument, which are copied from `one`. If both `other` and `one` have names, then the resulting locale also has a name.

### [edit] Parameters

other | - | another locale to copy
std_name | - | name of the system locale to use
f | - | pointer to a facet to merge with `other`
cat | - | the locale category used to identify the facets to merge with `other`
one | - | another locale to take facets from

### [edit] Exceptions

1-2)

(none) | (until C++11)
`noexcept` specification: noexcept | (since C++11)

3) std::runtime_error if the operating system has no locale named `std_name` or if `std_name` is NULL.
4) std::runtime_error if the operating system has no locale named `std_name`.
5) std::runtime_error if the operating system has no locale named `std_name` or if `std_name` is NULL.
6) std::runtime_error if the operating system has no locale named `std_name`.
7-8) (none)

### [edit] Notes

Overload 7 is typically called with its second argument, `f`, obtained directly from a new-expression: the locale is responsible for calling the matching `delete` from its own destructor.

### [edit] Example

Run this code

    #include <iostream>
    #include <locale>
    #include <codecvt>

    int main()
    {
        std::locale l1;  // l1 is a copy of the classic "C" locale
        std::locale l2("en_US.UTF-8"); // l2 is a unicode locale
        std::locale l3(l1, l2, std::locale::ctype); // l3 is "C" except for ctype, which is unicode
        std::locale l4(l1, new std::codecvt_utf8<wchar_t>); // l4 is "C" except for codecvt
        std::cout << "Locale names:\nl1: " << l1.name() << "\nl2: " << l2.name()
                   << "\nl3: " << l3.name() << "\nl4: " << l4.name() << '\n';
    }

Output:

    Locale names:
    l1: C
    l2: en_US.UTF-8
    l3: LC_CTYPE=en_US.UTF-8;LC_NUMERIC=C;LC_TIME=C;LC_COLLATE=C;LC_MONETARY=C;LC_MESSAGES=C;LC_PAPER=C;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=C;LC_IDENTIFICATION=C
    l4: *

### [edit] See also

(destructor) | destructs the locale and the facets whose reference count becomes zero (public member function) [edit]

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Category:

- unconditionally noexcept