GetThreadUILanguage function (winnls.h)

Article
06/29/2021

Returns the language identifier of the first user interface language for the current thread.

Syntax

LANGID GetThreadUILanguage();

Return value

Returns the identifier for a language explicitly associated with the thread by SetThreadUILanguage or SetThreadPreferredUILanguages. Alternatively, if no language has been explicitly associated with the current thread, the identifier can indicate a user or system user interface language.

Remarks

Calling this function is identical to calling GetThreadPreferredUILanguages with dwFlags set to MUI_MERGE_SYSTEM_FALLBACK | MUI_MERGE_USER_FALLBACK | MUI_LANGUAGE_ID and using the first language in the retrieved list.

The return value for this function does not provide useful information about a Language Interface Pack (LIP) language if that language corresponds to a supplemental locale. For such a language, the function returns the hexadecimal value "1400", which corresponds to LOCALE_CUSTOM_UI_DEFAULT if that language is specified in the user preferred UI languages list. If the language is not specified in the user preferred UI languages list, the function returns the value "1000", corresponding to LOCALE_CUSTOM_UNSPECIFIED.

C# Signature

[DllImport("Kernel32.dll", CharSet = CharSet.Auto)]
        static extern System.UInt16 GetThreadUILanguage();

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2008 [desktop apps only]
Target Platform	Windows
Header	winnls.h (include Windows.h)
Library	Kernel32.lib
DLL	Kernel32.dll