publisher_c_fast.cc

/*
 * Copyright (C) 2019 Open Source Robotics Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
*/
#include <signal.h>
#include <unistd.h>
#include <gz/msgs/stringmsg.pb.h>
#include <gz/transport/CIface.h>

static bool g_terminatePub = false;

//////////////////////////////////////////////////
/// \brief Function callback executed when a SIGINT or SIGTERM signals are
/// captured. This is used to break the infinite loop that publishes messages
/// and exit the program smoothly.
void signalHandler(int _signal)
{
  if (_signal == SIGINT || _signal == SIGTERM)
    g_terminatePub = true;
}

//////////////////////////////////////////////////
int main(int argc, char **argv)
{
  // Install a signal handler for SIGINT and SIGTERM.
  signal(SIGINT,  signalHandler);
  signal(SIGTERM, signalHandler);

  // Create a transport node.
  GzTransportNode *node = gzTransportNodeCreate(nullptr);
  GzTransportNode *nodeRed = gzTransportNodeCreate("red");

  const char *topic = "/foo";

  // Prepare the message.
  gz::msgs::StringMsg msg;
  msg.set_data("HELLO");

  // Get the size of the serialized message
#if GOOGLE_PROTOBUF_VERSION >= 3004000
  int size = msg.ByteSizeLong();
#else
  int size = msg.ByteSize();
#endif

  // Allocate space for the serialized message
  void *buffer = malloc(size);

  // Serialize the message.
  msg.SerializeToArray(buffer, size);

  // Prepare the message.
  gz::msgs::StringMsg msgRed;
  msgRed.set_data("RED HELLO");

  // Get the size of the serialized message
#if GOOGLE_PROTOBUF_VERSION >= 3004000
  int sizeRed = msgRed.ByteSizeLong();
#else
  int sizeRed = msgRed.ByteSize();
#endif

  // Allocate space for the serialized message
  void *bufferRed = malloc(sizeRed);

  // Serialize the message.
  msgRed.SerializeToArray(bufferRed, sizeRed);

  // Publish messages as fast as possible.
  while (!g_terminatePub)
  {
    gzTransportPublish(node, topic, buffer, msg.GetTypeName().c_str());
    gzTransportPublish(nodeRed, topic, bufferRed,
        msgRed.GetTypeName().c_str());

    printf("Publishing hello on topic %s.\n", topic);
  }

  free(buffer);
  free(bufferRed);
  gzTransportNodeDestroy(&node);
  gzTransportNodeDestroy(&nodeRed);

  return 0;
}