state.c

	
#define AWAIT(a) if (a != OK) continue;

status_t _connect(state_t *state)
{
    if (state >= CONNECTED) {
        return OK;
    }
    // do connect, return FAIL if failed
    state = CONNECTED;
    return OK;
}
 
status_t _register(state_t *state)
{
    if (state < CONNECTED) {
        return FAIL;
    }
    if (state > CONNECTED) {
        return OK;
    }
    // do register, return FAIL if failed
    state = DATA;
    return OK;
}
 
status_t _exchange_data(state_t *state)
{
  if (state != DATA) {
    return FAIL;
  }
  
  return OK;
}

void main() {
  state_t state = INITILIZED;
  
  while (true) {
      AWAIT(_connect(&state));
      AWAIT(_register(&state));
      AWAIT(_exchange_data(&state));
  }
}