rem: return(0);
add: return 0;
context: static int eca_jack_process_callback(jack_nframes_t nframes, void *arg){  AUDIO_IO_JACK_MANAGER* current = static_cast<AUDIO_IO_JACK_MANAGER*>(arg);  PROFILE_CE_STATEMENT(eca_jack_process_profile_pre());  if (current->exit_request_rep == 1) {     DEBUG_CFLOW_STATEMENT(cerr << "eca_jack_PROCESS: after exit!!!" << endl);     return 0;  }  /* try to get the driver lock; if it fails or connection    * is not fully establish, skip this processing cycle */  int ret = pthread_mutex_trylock(&current->engine_mod_lock_rep);  if (ret == 0) {    // DEBUG_CFLOW_STATEMENT(cerr << "eca_jack_PROCESS: got lock" << endl);        /* 1. transport control processing in "notransport" and "transport" mode */    if (current->mode_rep == AUDIO_IO_JACK_MANAGER::Transport_none ||	current->mode_rep == AUDIO_IO_JACK_MANAGER::Transport_send) {      /* execute one engine iteration */      if (current->is_running() == true) {	eca_jack_process_engine_iteration(nframes, current);      }      else {	eca_jack_process_mute(nframes, current);      }    }#if ECA_JACK_TRANSPORT_API >= 3    else {      /* 2. transport control processing in "slave" mode */      if (current->mode_rep == AUDIO_IO_JACK_MANAGER::Transport_send_receive ||	  current->mode_rep == AUDIO_IO_JACK_MANAGER::Transport_receive) {	eca_jack_process_timebase_slave(nframes, arg);      }      else { /* never reached */ }    }#endif    pthread_mutex_unlock(&current->engine_mod_lock_rep);    // DEBUG_CFLOW_STATEMENT(cerr << "eca_jack_PROCESS: released lock" << endl);  }  else {    DEBUG_CFLOW_STATEMENT(cerr << "eca_jack_PROCESS: couldn't get lock; muting" << endl);    eca_jack_process_mute(nframes, current);  }    PROFILE_CE_STATEMENT(eca_jack_process_profile_post());  return(0);}