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QLocale Class Reference

The QLocale class converts between numbers and their string representations in various languages. More...

Almost all the functions in this class are reentrant when Qt is built with thread support. The exception is setDefault().

#include <qlocale.h>

List of all member functions.

Public Members

Static Public Members

Detailed Description

The QLocale class converts between numbers and their string representations in various languages.

It is initialized with a country/language pair in its constructor and offers number-to-string and string-to-number conversion functions simmilar to those in QString. 

    QLocale egyptian(QLocale::Arabic, QLocale::Egypt);
    QString s1 = egyptian.toString(1.571429E+07, 'e');
    QString s2 = egyptian.toString(10);

    double d = egyptian.toDouble(s1);
    int s2 = egyptian.toInt(s2);

QLocale supports the concept of a default locale, which is determined from the system's locale settings at application startup. The default locale can be changed by calling the static member setDefault(). The default locale has the following effects: 

    QLocale::setDefault(QLocale(QLocale::Hebrew, QLocale::Israel));
    QLocale hebrew; // Constructs a default QLocale
    QString s1 = hebrew.toString(15714.3, 'e');

    bool ok;
    double d;

    QLocale::setDefault(QLocale::C);
    d = QString( "1234,56" ).toDouble(&ok); // ok == false
    d = QString( "1234.56" ).toDouble(&ok); // ok == true, d == 1234.56

    QLocale::setDefault(QLocale::German);
    d = QString( "1234,56" ).toDouble(&ok); // ok == true, d == 1234.56
    d = QString( "1234.56" ).toDouble(&ok); // ok == true, d == 1234.56

    QLocale::setDefault(QLocale(QLocale::English, QLocale::UnitedStates));
    str = QString( "%1 %L2 %L3" )
            .arg( 12345 )
            .arg( 12345 )
            .arg( 12345, 0, 16 );
    // str == "12345 12,345 3039"

When a language/country pair is specified in the constructor, one of three things can happen:

The "C" locale is identical to English/UnitedStates.

Use language() and country() to determine the actual language and country values used.

An alternative method for constructing a QLocale object is by specifying the locale name. 

    QLocale korean("ko");
    QLocale swiss("de_CH");

This constructor converts the locale name to a language/country pair; it does not use the system locale database.

All the methods in QLocale, with the exception of setDefault(), are reentrant.

See also QString::toDouble(), QString::arg(), and Text Related Classes.

The double-to-string and string-to-double conversion functions are covered by the following licenses:

Copyright (c) 1991 by AT&T.

Permission to use, copy, modify, and distribute this software for any purpose without fee is hereby granted, provided that this entire notice is included in all copies of any software which is or includes a copy or modification of this software and in all copies of the supporting documentation for such software.

THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR AT&T MAKES ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.

This product includes software developed by the University of California, Berkeley and its contributors.

Member Type Documentation

QLocale::Country

This enumerated type is used to specify a country.

QLocale::Language

This enumerated type is used to specify a language.

Member Function Documentation

QLocale::QLocale ()

Constructs a QLocale object initialized with the default locale.

See also setDefault().

QLocale::QLocale ( const QString & name )

Constructs a QLocale object with the specified name, which has the format "language[_country][.codeset][@modifier]" or "C", where:

If the string violates the locale format, or language is not a valid ISO 369 code, the "C" locale is used instead. If country is not present, or is not a valid ISO 3166 code, the most appropriate country is chosen for the specified language.

The language and country codes are converted to their respective Language and Country enums. After this conversion is performed the constructor behaves exactly like QLocale(Country, Language).

This constructor is much slower than QLocale(Country, Language).

See also name().

QLocale::QLocale ( Language language, Country country = AnyCountry )

Constructs a QLocale object with the specified language and country.

The language and country that are actually used can be queried using language() and country().

See also setDefault(), language(), and country().

QLocale::QLocale ( const QLocale & other )

Constructs a QLocale object as a copy of other.

QLocale QLocale::c () [static]

Returns a QLocale object initialized to the "C" locale.

See also system().

Country QLocale::country () const

Returns the country of this locale.

See also QLocale().

QString QLocale::countryToString ( Country country ) [static]

Returns a QString containing the name of country.

Language QLocale::language () const

Returns the language of this locale.

See also QLocale().

QString QLocale::languageToString ( Language language ) [static]

Returns a QString containing the name of language.

QString QLocale::name () const

Returns the language and country of this locale as a string of the form "language_country", where language is a lowercase, two-letter ISO 639 language code, and country is an uppercase, two-letter ISO 3166 country code.

See also QLocale().

QLocale & QLocale::operator= ( const QLocale & other )

Assigns other to this QLocale object and returns a reference to this QLocale object.

void QLocale::setDefault ( const QLocale & locale ) [static]

Warning: This function is not reentrant.

Sets the global default locale to locale. These values are used when a QLocale object is constructed with no arguments. If this function is not called, the system's locale is used.

Warning: In a multithreaded application, the default locale should be set at application startup, before any non-GUI threads are created.

See also system() and c().

QLocale QLocale::system () [static]

Returns a QLocale object initialized to the system locale.

double QLocale::toDouble ( const QString & s, bool * ok = 0 ) const

Returns the double represented by the localized string s, or 0.0 if the conversion failed.

If ok is not 0, reports failure by setting *ok to false and success by setting *ok to true.

Unlike QString::toDouble(), this function does not fall back to the "C" locale if the string cannot be interpreted in this locale. 

        bool ok;
        double d;

        QLocale c(QLocale::C);
        d = c.toDouble( "1234.56", &ok );  // ok == true, d == 1234.56
        d = c.toDouble( "1,234.56", &ok ); // ok == true, d == 1234.56
        d = c.toDouble( "1234,56", &ok );  // ok == false

        QLocale german(QLocale::German);
        d = german.toDouble( "1234,56", &ok );  // ok == true, d == 1234.56
        d = german.toDouble( "1.234,56", &ok ); // ok == true, d == 1234.56
        d = german.toDouble( "1234.56", &ok );  // ok == false

        d = german.toDouble( "1.234", &ok );    // ok == true, d == 1234.0

Notice that the last conversion returns 1234.0, because '.' is the thousands group separator in the German locale.

This function ignores leading and trailing whitespace.

See also toString() and QString::toDouble().

float QLocale::toFloat ( const QString & s, bool * ok = 0 ) const

Returns the float represented by the localized string s, or 0.0 if the conversion failed.

If ok is not 0, reports failure by setting *ok to false and success by setting *ok to true.

This function ignores leading and trailing whitespace.

See also toString().

int QLocale::toInt ( const QString & s, bool * ok = 0 ) const

Returns the int represented by the localized string s, or 0 if the conversion failed.

If ok is not 0, reports failure by setting *ok to false and success by setting *ok to true.

This function ignores leading and trailing whitespace.

See also toString().

Q_LONG QLocale::toLong ( const QString & s, bool * ok = 0 ) const

Returns the long int represented by the localized string s, or 0 if the conversion failed.

If ok is not 0, reports failure by setting *ok to false and success by setting *ok to true.

This function ignores leading and trailing whitespace.

See also toString().

Q_LLONG QLocale::toLongLong ( const QString & s, bool * ok = 0 ) const

Returns the long long int represented by the localized string s, or 0 if the conversion failed.

If ok is not 0, reports failure by setting *ok to false and success by setting *ok to true.

This function ignores leading and trailing whitespace.

See also toString().

short QLocale::toShort ( const QString & s, bool * ok = 0 ) const

Returns the short int represented by the localized string s, or 0 if the conversion failed.

If ok is not 0, reports failure by setting *ok to false and success by setting *ok to true.

This function ignores leading and trailing whitespace.

See also toString().

QString QLocale::toString ( Q_LLONG i ) const

Returns a localized string representation of i.

See also toLongLong().

QString QLocale::toString ( short i ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

See also toShort().

QString QLocale::toString ( ushort i ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

See also toUShort().

QString QLocale::toString ( int i ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

See also toInt().

QString QLocale::toString ( uint i ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

See also toUInt().

QString QLocale::toString ( Q_LONG i ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

See also toLong().

QString QLocale::toString ( Q_ULONG i ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

See also toULong().

QString QLocale::toString ( Q_ULLONG i ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

See also toULongLong().

QString QLocale::toString ( float i, char f = 'g', int prec = 6 ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

f and prec have the same meaning as in QString::number(double, char, int).

See also toDouble().

QString QLocale::toString ( double i, char f = 'g', int prec = 6 ) const

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

f and prec have the same meaning as in QString::number(double, char, int).

See also toDouble().

uint QLocale::toUInt ( const QString & s, bool * ok = 0 ) const

Returns the unsigned int represented by the localized string s, or 0 if the conversion failed.

If ok is not 0, reports failure by setting *ok to false and success by setting *ok to true.

This function ignores leading and trailing whitespace.

See also toString().

Q_ULONG QLocale::toULong ( const QString & s, bool * ok = 0 ) const

Returns the unsigned long int represented by the localized string s, or 0 if the conversion failed.

If ok is not 0, reports failure by setting *ok to false and success by setting *ok to true.

This function ignores leading and trailing whitespace.

See also toString().

Q_ULLONG QLocale::toULongLong ( const QString & s, bool * ok = 0 ) const

Returns the unsigned long long int represented by the localized string s, or 0 if the conversion failed.

If ok is not 0, reports failure by setting *ok to false and success by setting *ok to true.

This function ignores leading and trailing whitespace.

See also toString().

ushort QLocale::toUShort ( const QString & s, bool * ok = 0 ) const

Returns the unsigned short int represented by the localized string s, or 0 if the conversion failed.

If ok is not 0, reports failure by setting *ok to false and success by setting *ok to true.

This function ignores leading and trailing whitespace.

See also toString().

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Qt 3.3.6