RtlCheckBit - NtDoc

#ifndef _NTRTL_H

_Check_return_
FORCEINLINE
BOOLEAN
RtlCheckBit(
    _In_ PRTL_BITMAP BitMapHeader,
    _In_range_(<, BitMapHeader->SizeOfBitMap) ULONG BitPosition
    )
{
#ifdef _WIN64
    return BitTest64((LONG64 const *)BitMapHeader->Buffer, (LONG64)BitPosition);
#else
    return (((PLONG)BitMapHeader->Buffer)[BitPosition / 32] >> (BitPosition % 32)) & 0x1;
#endif
}

#endif
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