RtlULongToLongPtr - NtDoc

#ifndef _NTINTSAFE_H_INCLUDED_
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_SYSTEM | WINAPI_PARTITION_GAMES)
//
// ULONG -> LONG_PTR conversion
//
#ifdef _WIN64

_Must_inspect_result_
__inline
NTSTATUS
RtlULongToLongPtr(
    _In_ ULONG ulOperand,
    _Out_ _Deref_out_range_(==, ulOperand) LONG_PTR* plResult)
{
    C_ASSERT(sizeof(LONG_PTR) > sizeof(ULONG));
    *plResult = (LONG_PTR)ulOperand;
    return STATUS_SUCCESS;
}

#endif
#endif
#endif
View code on GitHub

#ifndef _NTINTSAFE_H_INCLUDED_
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_SYSTEM | WINAPI_PARTITION_GAMES)
//
// ULONG -> LONG_PTR conversion
//
#ifdef _WIN64
// ...
#else

#define RtlULongToLongPtr  RtlULongToLong

#endif
#endif
#endif
View code on GitHub