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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
       supported 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
       (typically 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.
       Otherwise, 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,  ob-
       tained 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		  Cor-
       rect 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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