Member offset in record by name

Hi,

    Is there any way that I can get member offset in a record by its name?

    EX:

            type
                  myRec=record
                        a:integer;
                        b:byte;
                  end;

     Member offset of b will be 4.   Because the sequence of b may changed
later someday. It will be inconvenient to revise source all the time.

Thanks,

Daniel