Supported NLS functions - XBOX Game Development Documentation

The National Language Support (NLS) functions help titles support language- and locale-specific behavior. Only API functions defined under the WINAPI_PARTITION_GAMES partition in WinNLS.h are available on XBOX.

APIs marked DEPRECATED still work on the GDK with the caveats documented on Microsoft Docs. Prefer the replacements.

Available functions

Function	State	Replacement
`EnumSystemLocalesEx`
`FindNLSStringEx`
`FoldStringA`
`GetACP`
`GetCurrencyFormatEx`
`GetGeoInfoEx`
`GetLocaleInfoEx`
`GetNumberFormatEx`
`GetStringTypeA`
`GetStringTypeExA`
`GetThreadLocale`
`GetUserDefaultGeoName`
`GetUserDefaultLocaleName`
`GetUserPreferredUILanguages`	NOT SUPPORTED	Always returns `en-US`
`IdnToAscii`
`IdnToUnicode`
`IsValidCodePage`
`IsValidLocaleName`
`LCIDToLocaleName`
`LCMapStringEx`
`LocaleNameToLCID`
`ResolveLocaleName`
`SetThreadLocale`
`CompareString`	DEPRECATED	`CompareStringEx`
`CompareStringA`	DEPRECATED	`CompareStringEx`
`EnumSystemLocalesA`	DEPRECATED	`EnumSystemLocalesEx`
`EnumSystemLocalesW`	DEPRECATED	`EnumSystemLocalesEx`
`FindNLSString`	DEPRECATED	`FindNLSStringEx`
`GetCPInfo`	DEPRECATED	Use Unicode
`GetCPInfoExA`	DEPRECATED	Use Unicode
`GetCPInfoExW`	DEPRECATED	Use Unicode
`GetCurrencyFormatA`	DEPRECATED	`GetCurrencyFormatEx`
`GetCurrencyFormatW`	DEPRECATED	`GetCurrencyFormatEx`
`GetGeoInfoA`	DEPRECATED	`GetGeoInfoEx`
`GetGeoInfoW`	DEPRECATED	`GetGeoInfoEx`
`GetLocaleInfoA`	DEPRECATED	`GetLocaleInfoEx`
`GetLocaleInfoW`	DEPRECATED	`GetLocaleInfoEx`
`GetNumberFormatA`	DEPRECATED	`GetNumberFormatEx`
`GetNumberFormatW`	DEPRECATED	`GetNumberFormatEx`
`GetUserGeoID`	DEPRECATED	`GetUserDefaultLocaleName`
`LCMapStringA`	DEPRECATED	`LCMapStringEx`
`LCMapStringW`	DEPRECATED	`LCMapStringEx`

Game OS behavior notes

Game OS NLS functions do not include the full linguistic casing tables that Windows has. Collation and casing operations always use ordinal values regardless of the locale. Do culture-sensitive casing and sorting as part of your localization process, not at runtime. Affected functions:

NLS
`LCMapStringEx`
`CompareStringEx`
`CompareString`
`CompareStringA`

Collation

Base	Wide	Multibyte
`std::collate`
`strcoll`	`wcscoll`	`_mbscoll`
`_stricoll`	`_wcsicoll`	`_mbsicoll`
`_strncoll`	`_wcsncoll`	`_mbsncoll`
`_strnicoll`	`_wcsnicoll`	`_mbsnicoll`

Uppercasing

Base	Variant	Wide variant
`std::toupper`	`toupper`	`towupper`
`_toupper`	`_toupper_l`	`_towupper_l`
`std::isupper`	`isupper`	`iswupper`
`_isupper_l`	`_iswupper_l`

Lowercasing

Base	Variant	Wide variant
`std::tolower`	`tolower`	`towlower`
`_tolower`	`_tolower_l`	`_towlower_l`
`std::islower`	`islower`	`iswlower`
`_islower_l`	`_iswlower_l`

This list isn’t exhaustive — other Standard C++ Library functions might depend on the impacted APIs.

XGameRuntime features reference — locale + region GDK surface complementing NLS

Last modified on August 20, 2026

Related topics

Localization and globalization overview Supported languages XFrontPanelIsSupported Console-supported languages Supported Azure regions

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