[
  uuid (22449651-4321-1234-4321-987654321010),
  version(1.0),
  endpoint ("ncalrpc:[ctxtrpc]")
]
interface sumup
{
  typedef [context_handle] void *SumUpContext;

  void InitSum([out, ref]
    SumUpContext *contextHandle);
  
  long SumUp([in] SumUpContext contextHandle,
    [in] short sumVal);

  void UnInitSum([in, out, ref]
    SumUpContext *contextHandle);
}