RtlIntPtrToUInt - NtDoc

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

#define RtlIntPtrToUInt    RtlLongLongToUInt

#endif
#endif
#endif
View code on GitHub

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

_Must_inspect_result_
__inline
NTSTATUS
RtlIntPtrToUInt(
    _In_ INT_PTR iOperand,
    _Out_ _Deref_out_range_(==, iOperand) UINT* puResult)
{
    NTSTATUS status;

    if (iOperand >= 0)
    {
        *puResult = (UINT)iOperand;
        status = STATUS_SUCCESS;
    }
    else
    {
        *puResult = UINT_ERROR;
        status = STATUS_INTEGER_OVERFLOW;
    }

    return status;
}

#endif
#endif
#endif
View code on GitHub