RtlMultiByteToUnicodeSize - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers

#ifndef _NTRTL_H

NTSYSAPI
NTSTATUS
NTAPI
RtlMultiByteToUnicodeSize(
    _Out_ PULONG BytesInUnicodeString,
    _In_reads_bytes_(BytesInMultiByteString) PCSTR MultiByteString,
    _In_ ULONG BytesInMultiByteString
    );

#endif
View code on GitHub

This function is documented in Windows Driver Kit.

Edit description on GitHub