RtlFormatMessageEx - NtDoc

#ifndef _NTRTL_H

NTSYSAPI
NTSTATUS
NTAPI
RtlFormatMessageEx(
    _In_ PWSTR MessageFormat,
    _In_ ULONG MaximumWidth,
    _In_ BOOLEAN IgnoreInserts,
    _In_ BOOLEAN ArgumentsAreAnsi,
    _In_ BOOLEAN ArgumentsAreAnArray,
    _In_ va_list *Arguments,
    _Out_writes_bytes_to_(Length, *ReturnLength) PWSTR Buffer,
    _In_ ULONG Length,
    _Out_opt_ PULONG ReturnLength,
    _Out_opt_ PPARSE_MESSAGE_CONTEXT ParseContext
    );

#endif
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