program dummy;

var
  a,
  b: TObject;

begin
  // some code to assign the pointers
  // ...

  // now evaluate the RTTI of two instantiated objects
  if a is b then
    ShowMessage('a is derived from b or same class');

  if a.classtype=b.classtype then
    ShowMessage('a and b are of the same class');

  // alternative to ClassType comparison (slower!)
  if a.ClassName=b.ClassName then
    ShowMessage('a and b are of the same class')
end.