Version: 3.2.1
wxUILocale Class Reference

#include <wx/uilocale.h>

Detailed Description

Query and modify locale used for the UI by the current platform.

UI locale determines all culture-dependent conventions used in the user interface, including numbers, currencies and dates formatting. It also determines the language used by the native dialogs, such as wxFileDialog, where different labels use the language corresponding to the current UI locale.

The UI locale is, in general, different from C locale set by the standard setlocale() function and affecting C standard library functions such as printf(), scanf(), strftime() and many others. Unfortunately, the relationship between C and UI locales is not the same depending on the platform: with wxGTK they must be the same, but under macOS C locale must not be changed, as doing this exposes bugs in the system. Because of this, applications can't generally count on C locale being set to any particular value and it is best to avoid using it, including implicitly via the standard C functions, in portable code. Instead, consider using wxNumberFormatter for parsing and formatting numbers according to the current UI locale or wxString::FromCDouble() and wxString::ToCDouble() functions for doing it always using period as decimal separator.

Localized applications should call wxUILocale::UseDefault() on startup to explicitly indicate that they opt-in using the current UI locale, even if this results in changing the global C locale, as is the case in wxGTK. Note that some platforms (MSW and macOS) will use default user locale for their standard dialogs even if this function is not called, but it is still necessary to call it to use the correct number and date formats and to avoid mixing messages in the user language with default formats not corresponding to it.

Please also note that under macOS to really use the user locale, it must be listed as a supported language in the application Info.plist file under CFBundleLocalizations key.

Unlike wxLocale class, this class doesn't affect the translations used by the application, see wxTranslations for doing this.

Library:  wxBase
Since
3.1.6

Public Member Functions

 wxUILocale (const wxLocaleIdent &localeId)
 Creates the locale corresponding to the given locale identifier. More...
 
int CompareStrings (const wxString &lhs, const wxString &rhs, int flags=wxCompare_CaseSensitive) const
 Compares two strings using comparison rules of this locale. More...
 
wxString GetName () const
 Get the platform-dependent name of the current locale. More...
 
wxLocaleIdent GetLocaleId () const
 Get the locale id from which the current locale was instantiated. More...
 
wxString GetInfo (wxLocaleInfo index, wxLocaleCategory cat=wxLOCALE_CAT_DEFAULT) const
 Query the locale for the specified information. More...
 
wxString GetLocalizedName (wxLocaleName name, wxLocaleForm form) const
 Query the locale for the specified localized name. More...
 
wxLayoutDirection GetLayoutDirection () const
 Query the layout direction of the current locale. More...
 
bool IsSupported () const
 Return true if locale is supported on the current system. More...
 

Static Public Member Functions

static bool UseDefault ()
 Configure the UI to use the default user locale. More...
 
static const wxUILocaleGetCurrent ()
 Get the object corresponding to the currently used locale. More...
 
static wxUILocale FromTag (const wxString &tag)
 Creates the local corresponding to the given language tag. More...
 
static void AddLanguage (const wxLanguageInfo &info)
 Adds custom, user-defined language to the database of known languages. More...
 
static const wxLanguageInfoFindLanguageInfo (const wxString &locale)
 This function may be used to find the language description structure for the given locale, specified either as a two letter ISO language code (for example, "pt"), a language code followed by the country code ("pt_BR") or a full, human readable, language description ("Portuguese_Brazil"). More...
 
static const wxLanguageInfoFindLanguageInfo (const wxLocaleIdent &localeId)
 This function may be used to find the language description structure for the given locale, specified as a locale identifier. More...
 
static const wxLanguageInfoGetLanguageInfo (int lang)
 Returns a pointer to wxLanguageInfo structure containing information about the given language or NULL if this language is unknown. More...
 
static wxString GetLanguageName (int lang)
 Returns English name of the given language or empty string if this language is unknown. More...
 
static wxString GetLanguageCanonicalName (int lang)
 Returns canonical name (see GetCanonicalName()) of the given language or empty string if this language is unknown. More...
 
static int GetSystemLanguage ()
 Tries to detect the user's default user interface language setting. More...
 
static int GetSystemLocale ()
 Tries to detect the user's default locale setting. More...
 

Constructor & Destructor Documentation

◆ wxUILocale()

wxUILocale::wxUILocale ( const wxLocaleIdent localeId)
explicit

Creates the locale corresponding to the given locale identifier.

In the simplest case, this can be used as following:

const wxUILocale loc(wxLocaleIdent().Language("fr"));
Represents a locale in a portable way.
Definition: uilocale.h:365
Query and modify locale used for the UI by the current platform.
Definition: uilocale.h:71

see wxLocaleIdent description for more details, including other ways of specifying the locale.

If localeId is not recognized or not supported, default ("C") locale is used instead. Additionally, if localeId is empty (see wxLocaleIdent::IsEmpty()), an assertion failure is triggered.

Member Function Documentation

◆ AddLanguage()

static void wxUILocale::AddLanguage ( const wxLanguageInfo info)
static

Adds custom, user-defined language to the database of known languages.

This database is used in conjunction with the first form of Init().

◆ CompareStrings()

int wxUILocale::CompareStrings ( const wxString lhs,
const wxString rhs,
int  flags = wxCompare_CaseSensitive 
) const

Compares two strings using comparison rules of this locale.

This function is useful for sorting the strings in the order expected by the user, e.g. by correctly sorting "ä" in the same way as "a" when using German locale, but not when using Swedish one, in which "ä" is sorted after "z".

It can be used both with the current locale, and with any other supported locale, even under systems not supporting changing the UI locale, such as macOS.

Parameters
lhsFirst comparing string.
rhsSecond comparing string.
flagsCan be used to specify whether to compare strings case-sensitively (default) or not, by specifying wxCompare_CaseInsensitive (note that this flag only works under MSW and Mac and is simply ignored under the other platforms).
Returns
-1 if lhs is less than rhs. 0 if lhs is equal to rhs. 1 if lhs is greater than rhs.

◆ FindLanguageInfo() [1/2]

static const wxLanguageInfo* wxUILocale::FindLanguageInfo ( const wxLocaleIdent localeId)
static

This function may be used to find the language description structure for the given locale, specified as a locale identifier.

Returns the information for the given language or NULL if this language is unknown. Note that even if the returned pointer is valid, the caller should not delete it.

See also
GetLanguageInfo()

◆ FindLanguageInfo() [2/2]

static const wxLanguageInfo* wxUILocale::FindLanguageInfo ( const wxString locale)
static

This function may be used to find the language description structure for the given locale, specified either as a two letter ISO language code (for example, "pt"), a language code followed by the country code ("pt_BR") or a full, human readable, language description ("Portuguese_Brazil").

Please note that only the underscore character is supported as the separator between language and region codes.

Returns the information for the given language or NULL if this language is unknown. Note that even if the returned pointer is valid, the caller should not delete it.

See also
GetLanguageInfo()

◆ FromTag()

static wxUILocale wxUILocale::FromTag ( const wxString tag)
static

Creates the local corresponding to the given language tag.

This is exactly equivalent to using wxUILocale constructor with the locale identifier returned by wxLocaleIdent::FromTag(), but shorter.

See wxLocaleIdent::FromTag() for more information about the syntax of the tag string.

◆ GetCurrent()

static const wxUILocale& wxUILocale::GetCurrent ( )
static

Get the object corresponding to the currently used locale.

If UseDefault() had been called, this object corresponds to the default user locale. Otherwise it corresponds to a generic locale similar to "C" locale, i.e. always uses period as decimal separator and m/d/y date format.

◆ GetInfo()

wxString wxUILocale::GetInfo ( wxLocaleInfo  index,
wxLocaleCategory  cat = wxLOCALE_CAT_DEFAULT 
) const

Query the locale for the specified information.

This function returns the value of the locale-specific option specified by the given index.

Parameters
indexOne of the elements of wxLocaleInfo enum.
catThe category to use with the given index or wxLOCALE_CAT_DEFAULT if the index can only apply to a single category.
Returns
The option value or empty string if the function failed.

◆ GetLanguageCanonicalName()

static wxString wxUILocale::GetLanguageCanonicalName ( int  lang)
static

Returns canonical name (see GetCanonicalName()) of the given language or empty string if this language is unknown.

See GetLanguageInfo() for a remark about special meaning of wxLANGUAGE_DEFAULT.

◆ GetLanguageInfo()

static const wxLanguageInfo* wxUILocale::GetLanguageInfo ( int  lang)
static

Returns a pointer to wxLanguageInfo structure containing information about the given language or NULL if this language is unknown.

Note that even if the returned pointer is valid, the caller should not delete it.

See AddLanguage() for the wxLanguageInfo description. As with Init(), wxLANGUAGE_DEFAULT has the special meaning if passed as an argument to this function and in this case the result of GetSystemLanguage() is used.

◆ GetLanguageName()

static wxString wxUILocale::GetLanguageName ( int  lang)
static

Returns English name of the given language or empty string if this language is unknown.

See GetLanguageInfo() for a remark about special meaning of wxLANGUAGE_DEFAULT.

◆ GetLayoutDirection()

wxLayoutDirection wxUILocale::GetLayoutDirection ( ) const

Query the layout direction of the current locale.

Returns
The layout direction or wxLayout_Default if the function failed.

◆ GetLocaleId()

wxLocaleIdent wxUILocale::GetLocaleId ( ) const

Get the locale id from which the current locale was instantiated.

◆ GetLocalizedName()

wxString wxUILocale::GetLocalizedName ( wxLocaleName  name,
wxLocaleForm  form 
) const

Query the locale for the specified localized name.

Parameters
nameOne of the elements of wxLocaleName enum.
formThe representation form requested.
Returns
The localized name value or empty string if the function failed.

◆ GetName()

wxString wxUILocale::GetName ( ) const

Get the platform-dependent name of the current locale.

This name can be used in diagnostic messages.

◆ GetSystemLanguage()

static int wxUILocale::GetSystemLanguage ( )
static

Tries to detect the user's default user interface language setting.

Returns the wxLanguage value or wxLANGUAGE_UNKNOWN if the language-guessing algorithm failed.

Note
Where possible this function returns the user's preferred UI language. This may be, and usually is, the same as the user's default locale, but it's not the same thing. If retrieving the preferred UI language is not supported by the operating system (for example, Windows 7 and below), the user's default locale will be used.
See also
wxTranslations::GetBestTranslation().

◆ GetSystemLocale()

static int wxUILocale::GetSystemLocale ( )
static

Tries to detect the user's default locale setting.

Returns the wxLanguage value or wxLANGUAGE_UNKNOWN if the locale-guessing algorithm failed.

Note
This function works with locales and returns the user's default locale. This may be, and usually is, the same as their preferred UI language, but it's not the same thing. Use wxTranslation to obtain language information.
Since
3.1.7
See also
wxTranslations::GetBestTranslation().

◆ IsSupported()

bool wxUILocale::IsSupported ( ) const

Return true if locale is supported on the current system.

If this function returns false, the other functions of this class, such as GetInfo() and CompareStrings(), behave as in "C" locale, i.e. it's still safe to call them, but their results don't reflect the rules for the locale in question, but just use the default (i.e. US English) conventions.

◆ UseDefault()

static bool wxUILocale::UseDefault ( )
static

Configure the UI to use the default user locale.

Localized applications should call this functions as early as possible during the program startup, e.g. in the very beginning of the overridden wxApp::OnInit().

Note that under most Unix systems (but not macOS) this function changes the C locale to the locale specified by the environment variables and so affects the results of calling C functions such as sprintf() etc which can use comma, rather than period, as decimal separator. The wxString::ToCDouble() and wxString::FromCDouble() functions can be used for parsing and formatting floating point numbers using period as decimal separator independently of the current locale.

Returns
true on success or false if the default locale couldn't be set