Creates an snapshot of a locale by querying the program's environment to determine the formatting conventions in effect at the moment of instantiation. More...

#include <rw/tools/localesnapshot.h>

Inheritance diagram for RWLocaleSnapshot:

Public Member Functions
	RWLocaleSnapshot ()

	RWLocaleSnapshot (const char *localeName)

RWCString	asString (const struct tm t, const char fmt, const RWZone &z=RWZone::local()) const

virtual RWCString	asString (const struct tm *, char, const RWZone &=RWZone::local()) const

virtual RWCString	asString (long) const

virtual RWCString	asString (unsigned long) const

virtual RWCString	asString (double, int=6, bool=0) const

virtual RWCString	asString (long double, int=10, bool=0) const

virtual const RWCString &	currency_symbol () const

virtual const RWCString &	decimal_point () const

virtual const RWCString &	grouping () const

virtual const RWCString &	int_curr_symbol () const

virtual const RWCString &	locale_name () const

virtual const RWCString &	mon_decimal_point () const

virtual const RWCString &	mon_grouping () const

virtual const RWCString &	mon_thousands_sep () const

virtual RWCString	moneyAsString (double, RWLocaleSnapshot::CurrSymbol=LOCAL) const

virtual int	monthIndex (const RWCString &) const

virtual const RWCString &	negative_sign () const

virtual const RWCString &	positive_sign () const

virtual bool	stringToDate (const RWCString &, struct tm *) const

virtual bool	stringToMoney (const RWCString &, double *, RWLocaleSnapshot::CurrSymbol=LOCAL) const

virtual bool	stringToNum (const RWCString &, double *) const

virtual bool	stringToNum (const RWCString &, long *) const

virtual bool	stringToNum (const RWCString &, unsigned long *) const

virtual bool	stringToTime (const RWCString &, struct tm *) const

virtual const RWCString &	thousands_sep () const

virtual int	weekdayIndex (const RWCString &) const

Public Member Functions inherited from RWLocale
RWCString	asString (const struct tm tmbuf, const char format, const RWZone &zone=RWZone::local()) const

const RWLocale *	imbue (std::ios &stream) const

Public Attributes
RWCString	currency_symbol_

RWCString	decimal_point_

char	frac_digits_

RWCString	grouping_

RWCString	int_curr_symbol_

char	int_frac_digits_

RWCString	mon_decimal_point_

RWCString	mon_grouping_

RWCString	mon_thousands_sep_

char	n_cs_precedes_

char	n_sep_by_space_

char	n_sign_posn_

RWCString	negative_sign_

char	p_cs_precedes_

char	p_sep_by_space_

char	p_sign_posn_

RWCString	positive_sign_

RWCString	thousands_sep_

Additional Inherited Members
Public Types inherited from RWLocale
enum	CurrSymbol { NONE, LOCAL, INTL }

Static Public Member Functions inherited from RWLocale
static const RWLocale *	defaultLocale ()

static const RWLocale &	global ()

static const RWLocale *	global (const RWLocale *loc)

static const RWLocale &	of (std::ios &stream)

static const RWLocale *	unimbue (std::ios &stream)

Detailed Description

The class RWLocaleSnapshot implements the RWLocale interface using C Standard Library facilities. To use it, the program creates an RWLocaleSnapshot instance. The constructor of the instance queries the program's environment (using C Standard Library functions such as localeconv(), strftime(), and, if available, vendor-specific library functions) to determine the formatting conventions in effect at the moment of instantiation. When done, the locale can then be switched and another instance of RWLocaleSnapshot created.

By creating multiple instances of RWLocaleSnapshot, your program can have more than one locale active at the same time, something that is difficult to do with the C Standard Library facilities.

Note: RWLocaleSnapshot does not encapsulate character set, collation, or message information.

Class RWLocaleSnapshot contains a set of public data members initialized by its constructor with information extracted from its execution environment.

For a description of the static members of the RWLocale interface that operate on objects of type RWLocaleSnapshot, see the RWLocale class description.

Synopsis: #include <locale.h>

#include <rw/locale.h>

RWLocaleSnapshot ourLocale(""); // encapsulate user's formats

Persistence: None

Example

Note: To ensure that the asString() methods in this example correctly format the output, you must first install on your system any locale you request before invoking RWLocaleSnapshot().

#include <rw/tools/datetime.h>
#include <rw/locale.h>
#include <rw/cstring.h>
#if defined(_WIN32)
   // french should be a valid French locale name on Windows
  #define FRENCH_LOCALE_NAME "french"
#elif defined(__HP_aCC)
  #define FRENCH_LOCALE_NAME "fr_FR.utf8"
#else
   // fr_FR should be a valid French locale name on most Unices
  #define FRENCH_LOCALE_NAME "fr_FR"
#endif
int main()
{
    RWLocaleSnapshot us("C");
    RWLocaleSnapshot french(FRENCH_LOCALE_NAME); // or vendor-specific
    RWCString americanDate ("10 June 2025");
    RWCString frenchDate   ("10 Juin 2025");
    RWDateTime d(frenchDate, RWDateTime::setDate, french); // OK
    std::cout << frenchDate << ((d.isValid()) ? " IS " : " IS NOT ")
              << "a valid date (french locale)." << std::endl << std::endl;
    RWDateTime bad = RWDateTime(frenchDate, RWDateTime::setDate);
    std::cout << frenchDate;
    std::cout << ((bad.isValid() && bad == d) ? " IS " : " IS NOT ")
              << "a valid date (default locale)." << std::endl << std::endl;
    bad = RWDateTime(americanDate, RWDateTime::setDate, french);
    std::cout << americanDate;
    std::cout << ((bad.isValid() && bad == d) ? " IS " : " IS NOT ")
              << "a valid date (french locale)." << std::endl << std::endl;
    std::cout << d << std::endl;
    std::cout << d.asString('x') << std::endl;
    std::cout << d.asString('x', french) << std::endl;
    return 0;
}

Program output:

10 Juin 2025 IS a valid date (french locale).
10 Juin 2025 IS NOT a valid date (default locale).
10 June 2025 IS a valid date (french locale).
Tue Jun 10 00:00:00 2025
06/10/25
10.06.2025

Constructor & Destructor Documentation

RWLocaleSnapshot::RWLocaleSnapshot ( )

Constructs an RWLocale object by extracting formats from the current locale environment.

RWLocaleSnapshot::RWLocaleSnapshot ( const char * localeName )

Constructs an RWLocale object by extracting formats from the global locale environment. It uses the C++ Standard Library function std::setlocale() to set the named locale, and then restores the previous global locale after formats have been extracted. If localeName is 0, it uses the current locale. The most useful locale name is the empty string, "", which is a synonym for the user's chosen locale (usually specified by the environment variable LANG).

Member Function Documentation

RWCString RWLocaleSnapshot::asString	(	const struct tm *	t,
		const char *	fmt,
		const RWZone &	z = `RWZone::local()`
	)		const

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

virtual RWCString RWLocaleSnapshot::asString	(	const struct tm *	,
		char	,
		const RWZone &	= `RWZone::local()`
	)		const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual RWCString RWLocaleSnapshot::asString ( long ) const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual RWCString RWLocaleSnapshot::asString ( unsigned long ) const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual RWCString RWLocaleSnapshot::asString	(	double	,
		int	= `6`,
		bool	= `0`
	)		const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual RWCString RWLocaleSnapshot::asString	(	long	double,
		int	= `10`,
		bool	= `0`
	)		const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::currency_symbol ( ) const

inlinevirtual

Returns a string to use as the currency symbol for this locale.

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::decimal_point ( ) const

inlinevirtual

Returns a string to use as the numerical decimal separator.

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::grouping ( ) const

inlinevirtual

Returns a string identifying the number of digits to be included in a numerical group. A group is simply the digits between adjacent thousand's separators.

Each character of the string is an integer that specifies the number of digits in a group, starting with the right most group.

If the value is equal to 0, the previous element is used repeatedly for the remainder of the digits.
If the value is equal to CHAR_MAX, no further grouping is to be performed.

Example: "\3" // Specifies the United States grouping system.

// For example, "1,000,000"

"\3\2" // Specifies the Nepalese grouping system.

// For example, "1,00,00,000"

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::int_curr_symbol ( ) const

inlinevirtual

Returns a string to use as the international currency symbol.

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::locale_name ( ) const

inlinevirtual

Returns the name of the encapsulated std::locale.

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::mon_decimal_point ( ) const

inlinevirtual

Returns a string to use as the monetary decimal separator.

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::mon_grouping ( ) const

inlinevirtual

Returns a string identifying the number of digits to be included in a numerical group. A group is simply the digits between adjacent thousand's separators.

Each character of the string is an integer that specifies the number of digits in a group, starting with the right most group.

If the value is equal to 0, the previous element is used repeatedly for the remainder of the digits.

If the value is equal to CHAR_MAX, no further grouping is to be performed.

See Example under grouping().

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::mon_thousands_sep ( ) const

inlinevirtual

Returns a string to use as the monetary thousands separator.

Implements RWLocale.

virtual RWCString RWLocaleSnapshot::moneyAsString	(	double	,
		RWLocaleSnapshot::CurrSymbol	= `LOCAL`
	)		const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual int RWLocaleSnapshot::monthIndex ( const RWCString & str ) const

virtual

Interprets its argument as a full or abbreviated month name, returning values 1 through 12 to represent (respectively) January through December, or 0 for an error. Ignores leading white space.

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::negative_sign ( ) const

inlinevirtual

Returns a string to use as the negative sign.

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::positive_sign ( ) const

inlinevirtual

Returns a string to use as the positive sign.

Implements RWLocale.

virtual bool RWLocaleSnapshot::stringToDate	(	const RWCString &	,
		struct tm *
	)		const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual bool RWLocaleSnapshot::stringToMoney	(	const RWCString &	,
		double *	,
		RWLocaleSnapshot::CurrSymbol	= `LOCAL`
	)		const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual bool RWLocaleSnapshot::stringToNum	(	const RWCString &	,
		double *
	)		const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual bool RWLocaleSnapshot::stringToNum	(	const RWCString &	,
		long *
	)		const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual bool RWLocaleSnapshot::stringToNum	(	const RWCString &	,
		unsigned long *
	)		const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual bool RWLocaleSnapshot::stringToTime	(	const RWCString &	,
		struct tm *
	)		const

virtual

Redefined from RWLocale

Note: These virtual functions follow the interface described under class RWLocale. They generally work by converting values to and from strings using the rules specified by the std::lconv values (see http://en.cppreference.com/w/cpp/locale/lconv) encapsulated in self.

Implements RWLocale.

virtual const RWCString& RWLocaleSnapshot::thousands_sep ( ) const

inlinevirtual

Returns a string to use as the numerical thousands separator.

Implements RWLocale.

virtual int RWLocaleSnapshot::weekdayIndex ( const RWCString & str ) const

virtual

Interprets its argument as a full or abbreviated weekday name, returning values 1 through 7 to represent (respectively) Monday through Sunday, or 0 for an error.

Implements RWLocale.