GNURadio no setup_rpc call, MWE c++ implementation

/* -*- c++ -*- */
/*
 * Copyright 2016 <+YOU OR YOUR COMPANY+>.
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this software; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <gnuradio/io_signature.h>
#include "cptest_impl.h"

namespace gr {
  namespace ccsds {

    cptest::sptr
    cptest::make()
    {
      return gnuradio::get_initial_sptr(new cptest_impl());
    }

    /*
     * The private constructor
     */
    cptest_impl::cptest_impl()
      : gr::sync_block("cptest",
              gr::io_signature::make(0, 0, 0),
              gr::io_signature::make(0, 0, 0))
    {
      printf("constructor()\n");

      // register input
      message_port_register_in(pmt::mp("in"));
      set_msg_handler(pmt::mp("in"), boost::bind(&cptest_impl::process_frame, this, _1));
    }

    void cptest_impl::process_frame(pmt::pmt_t msg_in) {
      printf("process frame()\n");
    }

    /*
     * Our virtual destructor.
     */
    cptest_impl::~cptest_impl() { }

    int cptest_impl::work(int noutput_items,
        gr_vector_const_void_star &input_items,
        gr_vector_void_star &output_items)
    {
      // Do nothing here and return 0 samples processed
      return 0;
    }

    void cptest_impl::setup_rpc()
    {
      printf("setup_rpc()\n");
      #ifdef GR_CTRLPORT
    add_rpc_variable(
        rpcbasic_sptr(new rpcbasic_register_get<cptest, float>(
        alias(), "testval",
        &cptest::get_testf,
        pmt::mp(-2.0f), pmt::mp(2.0f), pmt::mp(0.0f),
        "1", "Test value", RPC_PRIVLVL_MIN,
        DISPTIME | DISPOPTSTRIP))
    );
      #endif
    }
  } /* namespace ccsds */
} /* namespace gr */