TIdInt64Parts = packed record
  case Integer of
    0: (LowPart: LongWord;
        HighPart: LongWord;);
    1: (QuadPart: Int64;);
end;

TIdInt64Parts is a packed record type used to 64-bit values on the Windows and Linux platforms. TIdInt64Parts is used in HostToNetwork and NetworkToHost to convert native Int64 values to their Host and Network representations. 

Use the LowPart and HighPart member fields to access the LongWord values that make up the 64-bit Integer data type. 

Use the QuadPart member field to access the Int64 value that makes up the 64-bit Integer data type.