diff --git a/CMakeLists.txt b/CMakeLists.txt new file mode 100644 index 0000000..79d9593 --- /dev/null +++ b/CMakeLists.txt @@ -0,0 +1,17 @@ +cmake_minimum_required(VERSION 2.8.3) +project(beginner_tutorials) + +## Find catkin and any catkin packages +find_package(catkin REQUIRED COMPONENTS roscpp rospy std_msgs genmsg) + +## Declare a catkin package +catkin_package() + +## Build talker and listener +include_directories(include ${catkin_INCLUDE_DIRS}) + +add_executable(talker src/talker.cpp) +target_link_libraries(talker ${catkin_LIBRARIES}) + +add_executable(listener src/listener.cpp) +target_link_libraries(listener ${catkin_LIBRARIES}) diff --git a/package.xml b/package.xml new file mode 100644 index 0000000..68b09b5 --- /dev/null +++ b/package.xml @@ -0,0 +1,68 @@ + + + beginner_tutorials + 0.0.0 + The beginner_tutorials package + + + + + sakshi + + + + + + TODO + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + catkin + roscpp + rospy + std_msgs + roscpp + rospy + std_msgs + roscpp + rospy + std_msgs + + + + + + + + diff --git a/src/listener.cpp b/src/listener.cpp new file mode 100644 index 0000000..e76ee5f --- /dev/null +++ b/src/listener.cpp @@ -0,0 +1,58 @@ +#include "ros/ros.h" +#include "std_msgs/String.h" + +/** + * This tutorial demonstrates simple receipt of messages over the ROS system. + */ +void chatterCallback(const std_msgs::String::ConstPtr& msg) +{ + ROS_INFO("I heard: [%s]", msg->data.c_str()); +} + +int main(int argc, char **argv) +{ + /** + * The ros::init() function needs to see argc and argv so that it can perform + * any ROS arguments and name remapping that were provided at the command line. + * For programmatic remappings you can use a different version of init() which takes + * remappings directly, but for most command-line programs, passing argc and argv is + * the easiest way to do it. The third argument to init() is the name of the node. + * + * You must call one of the versions of ros::init() before using any other + * part of the ROS system. + */ + ros::init(argc, argv, "listener"); + + /** + * NodeHandle is the main access point to communications with the ROS system. + * The first NodeHandle constructed will fully initialize this node, and the last + * NodeHandle destructed will close down the node. + */ + ros::NodeHandle n; + + /** + * The subscribe() call is how you tell ROS that you want to receive messages + * on a given topic. This invokes a call to the ROS + * master node, which keeps a registry of who is publishing and who + * is subscribing. Messages are passed to a callback function, here + * called chatterCallback. subscribe() returns a Subscriber object that you + * must hold on to until you want to unsubscribe. When all copies of the Subscriber + * object go out of scope, this callback will automatically be unsubscribed from + * this topic. + * + * The second parameter to the subscribe() function is the size of the message + * queue. If messages are arriving faster than they are being processed, this + * is the number of messages that will be buffered up before beginning to throw + * away the oldest ones. + */ + ros::Subscriber sub = n.subscribe("chatter", 1000, chatterCallback); + + /** + * ros::spin() will enter a loop, pumping callbacks. With this version, all + * callbacks will be called from within this thread (the main one). ros::spin() + * will exit when Ctrl-C is pressed, or the node is shutdown by the master. + */ + ros::spin(); + + return 0; +} \ No newline at end of file diff --git a/src/talker.cpp b/src/talker.cpp new file mode 100644 index 0000000..29537f4 --- /dev/null +++ b/src/talker.cpp @@ -0,0 +1,85 @@ +#include "ros/ros.h" +#include "std_msgs/String.h" + +#include + +/** + * This tutorial demonstrates simple sending of messages over the ROS system. + */ +int main(int argc, char **argv) +{ + /** + * The ros::init() function needs to see argc and argv so that it can perform + * any ROS arguments and name remapping that were provided at the command line. + * For programmatic remappings you can use a different version of init() which takes + * remappings directly, but for most command-line programs, passing argc and argv is + * the easiest way to do it. The third argument to init() is the name of the node. + * + * You must call one of the versions of ros::init() before using any other + * part of the ROS system. + */ + ros::init(argc, argv, "talker"); + + /** + * NodeHandle is the main access point to communications with the ROS system. + * The first NodeHandle constructed will fully initialize this node, and the last + * NodeHandle destructed will close down the node. + */ + ros::NodeHandle n; + + /** + * The advertise() function is how you tell ROS that you want to + * publish on a given topic name. This invokes a call to the ROS + * master node, which keeps a registry of who is publishing and who + * is subscribing. After this advertise() call is made, the master + * node will notify anyone who is trying to subscribe to this topic name, + * and they will in turn negotiate a peer-to-peer connection with this + * node. advertise() returns a Publisher object which allows you to + * publish messages on that topic through a call to publish(). Once + * all copies of the returned Publisher object are destroyed, the topic + * will be automatically unadvertised. + * + * The second parameter to advertise() is the size of the message queue + * used for publishing messages. If messages are published more quickly + * than we can send them, the number here specifies how many messages to + * buffer up before throwing some away. + */ + ros::Publisher chatter_pub = n.advertise("chatter", 1000); + + ros::Rate loop_rate(10); + + /** + * A count of how many messages we have sent. This is used to create + * a unique string for each message. + */ + int count = 0; + while (ros::ok()) + { + /** + * This is a message object. You stuff it with data, and then publish it. + */ + std_msgs::String msg; + + std::stringstream ss; + ss << "hello world " << count; + msg.data = ss.str(); + + ROS_INFO("%s", msg.data.c_str()); + + /** + * The publish() function is how you send messages. The parameter + * is the message object. The type of this object must agree with the type + * given as a template parameter to the advertise<>() call, as was done + * in the constructor above. + */ + chatter_pub.publish(msg); + + ros::spinOnce(); + + loop_rate.sleep(); + ++count; + } + + + return 0; +} \ No newline at end of file