#ifndef _NTRTL_H

// rev from GetUILanguageInfo
NTSYSAPI
NTSTATUS
NTAPI
RtlGetUILanguageInfo(
    _In_ ULONG Flags,
    _In_ PCZZWSTR Languages,
    _Out_writes_opt_(*NumberOfFallbackLanguages) PZZWSTR FallbackLanguages,
    _Inout_opt_ PULONG NumberOfFallbackLanguages,
    _Out_ PULONG Attributes
    );

#endif
View code on GitHub