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std::locale::locale(3)	       C++ Standard Libary	  std::locale::locale(3)

NAME
     std::locale::locale - std::locale::locale

Synopsis
	Defined in header <locale>
	locale() throw();					 (until C++11)
	locale() noexcept;					 (since C++11)
	locale(        const	    locale&	   other	)	throw();
     (until C++11)
	locale(       const	  locale&	 other	      )        noexcept;
     (since C++11)
	explicit locale( const char* std_name );		 (3)
	explicit   locale(   const   std::string&   std_name   );	     (4)
     (since C++11)
	locale( const locale& other, const char*	 (1)	 (5)
	std_name, category cats );			     (2)
	locale(   const   locale&   other,   const   std::string&	     (6)
     (since C++11)
	std_name, category cats );
	template< class Facet > 				 (7)
	locale( const locale& other, Facet* f );
	locale( const locale& other, const locale& one, 	 (8)
	category cats );

	Constructs 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 sup-
     ported by the
	operating system. The locale constructed in this manner has a name.
	4) Equivalent to locale(std_name.c_str()).
	5) Constructs a copy of other except for all the  facets  identified  by
     the cats
	argument,  which  are  copied  from  the system locale identified by its
     std_name. The
	locale constructed in this manner has a name if and only if other has  a
     name.
	6) Equivalent to locale(other, std_name.c_str(), cats).
	7)  Constructs a copy of other except for the facet of type Facet (typi-
     cally deduced
	from the type of the argument) which is installed from f. If f is a null
     pointer,
	the constructed locale is a full copy of  other.  The  program	is  ill-
     formed if Facet
	is not a facet or it is a volatile-qualified facet.
	If  f is null, the constructed locale has the same name as other. Other-
     wise, the
	constructed locale has no name.
	8) Constructs a copy of other except for all the  facets  identified  by
     the cats
	argument, which are copied from one.
	If  cats  is equal to locale::none, the constructed locale has a name if
     and only if
	other has a name. Otherwise, the constructed locale has a  name  if  and
     only if other
	and one both have names.

Parameters
	other	 - another locale to copy
	std_name - name of the system locale to use
	f	 - pointer to a facet to merge with other
	cats	  -  the  facet  categories used to identify the facets to merge
     with other
	one	 - another locale to take facets from

Exceptions
	3,5) std::runtime_error if the operating  system  has  no  locale  named
     std_name or if
	std_name is a null pointer.
	4,6)  std::runtime_error  if  the  operating  system has no locale named
     std_name.

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.

Example
     // Run this code

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

      std::ostream& operator<< (std::ostream& os, std::locale const& loc)
      {
	  if (loc.name().length() <= 80)
	      return os << loc.name() << '\n';

	  for (const auto c : loc.name())
	      c != ';' ? os << c : os << "\n	";
	  return os << '\n';
      }

      int main()
      {
	  // l1 is a copy of the classic "C" locale
	  std::locale l1;
	  // l2 is a unicode locale
	  std::locale l2("en_US.UTF-8");
	  // l3 is "C" except for ctype, which is unicode
	  std::locale l3(l1, l2, std::locale::ctype);
	  // l4 is "C" except for codecvt
	  std::locale l4(l1, new std::codecvt_utf8<wchar_t>);

	  std::cout
	      << "Locale names:\n"
	      << "l1: " << l1 << "l2: " << l2
	      << "l3: " << l3 << "l4: " << l4;
      }

Possible 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: *

	Defect reports

	The following behavior-changing defect	reports  were  applied	retroac-
     tively to
	previously published C++ standards.

	   DR	  Applied  to	      Behavior as published		 Correct
     behavior
	LWG 436  C++98	    for overload (7), it  was  unclear	     it  can  be
     const-qualified,
			    whether   Facet  can  be  cv-qualified	but  not
     volatile-qualified
	LWG 2295 C++98	    for overload (7), the  constructed	    it	has  the
     name of other
			    locale had no name even if f is null

See also
	destructor    destructs  the locale and the facets whose reference count
     becomes zero
		     (public member function)

External links
	1.  List of Windows locale names.
	2.  List of Linux locale names.

http://cppreference.com 	   2024.06.10		  std::locale::locale(3)
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