RtlULongPtrToLong - NtDoc

#ifndef _NTINTSAFE_H_INCLUDED_
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_SYSTEM | WINAPI_PARTITION_GAMES)

//
// ULONG_PTR -> LONG conversion
//
_Must_inspect_result_
__inline
NTSTATUS
RtlULongPtrToLong(
    _In_ ULONG_PTR ulOperand,
    _Out_ _Deref_out_range_(==, ulOperand) LONG* plResult)
{
    NTSTATUS status;
    
    if (ulOperand <= LONG_MAX)
    {
        *plResult = (LONG)ulOperand;
        status = STATUS_SUCCESS;
    }
    else
    {
        *plResult = LONG_ERROR;
        status = STATUS_INTEGER_OVERFLOW;
    }
    
    return status;
}

#endif
#endif
View code on GitHub