text: /*
   * Copyright © 2008-2010 Stéphane Raimbault <stephane.raimbault@gmail.com>
   *
   * This program 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 of the License, or
   * (at your option) any later version.
   *
   * This program 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 program.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  #include <stdio.h>
  #include <unistd.h>
  #include <stdlib.h>
  #include <errno.h>
  
  #include <modbus.h>
  
  int main(int argc, char** argv)
  {
      int socket;
      modbus_t *ctx;
      modbus_mapping_t *mb_mapping;
  
      if(argc != 2) {
        fprintf(stderr, "Usage: %s <PORT>\n\n", argv[0]);
        exit(1);
      }
  
      ctx = modbus_new_tcp("127.0.0.1", atoi(argv[1]));
      /* modbus_set_debug(ctx, TRUE); */
  
      mb_mapping = modbus_mapping_new(500, 500, 500, 500);
      if (mb_mapping == NULL) {
          fprintf(stderr, "Failed to allocate the mapping: %s\n",
                  modbus_strerror(errno));
          modbus_free(ctx);
          return -1;
      }
  
      socket = modbus_tcp_listen(ctx, 1);
      modbus_tcp_accept(ctx, &socket);
  
      for (;;) {
          uint8_t query[MODBUS_TCP_MAX_ADU_LENGTH];
          int rc;
  
          rc = modbus_receive(ctx, query);
          if (rc != -1) {
              /* rc is the query size */
              modbus_reply(ctx, query, rc, mb_mapping);
          } else {
              /* Connection closed by the client or error */
              break;
          }
      }
  
      printf("Quit the loop: %s\n", modbus_strerror(errno));
  
      modbus_mapping_free(mb_mapping);
      modbus_close(ctx);
      modbus_free(ctx);
  
      return 0;
  }
  