<metadata>
   <boxdefault>
    <interface value="C4SNet"/>
   </boxdefault>
 </metadata>


 net synchro {
   net join connect [|{state}, {inval}|];
   net id connect [{state} -> {state}];
   box dec((state, inval) -> (state) | (outval));

} connect (join .. (id | dec)) * {outval};


This is dec.c
void *dec( void *hnd, c4snet_data_t *state, c4snet_data_t *inval)
{
  int int_a, int_b;
  c4snet_data_t *resultA, *resultB;

  int_a= *(int *)C4SNetDataGetData(state);
  int_b = *(int *) C4SNetDataGetData(inval);

  if (int_a != 0) {
    resultA = C4SNetDataCreate( CTYPE_int, &int_b);
    C4SNetOut( hnd, 1, resultA);
  } else {
    resultB = C4SNetDataCreate( CTYPE_int, &int_b);
    C4SNetOut( hnd, 2, resultB);
 }

  C4SNetDataFree(state);
  C4SNetDataFree(inval);
  return( hnd);
}


This is correct snet file:
<metadata>
  <boxdefault>
    <interface value="C4SNet"/>
  </boxdefault>
</metadata>


net synchro {
  net join connect [|{state}, {inval}|];
  net id connect [{inval} -> {inval}];
  box dec((state, inval) -> (state) | (outval));

} connect (join .. (id | dec)) * {outval};