Difference between revisions of "Writing a Simple Publisher and Subscriber (C++)"
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==Writing a Simple Publisher and Subscriber (C++)== | ==Writing a Simple Publisher and Subscriber (C++)== | ||
| − | |||
1) In a terminal, move to your beginner_tutorials folder: | 1) In a terminal, move to your beginner_tutorials folder: | ||
<nowiki>cd ~/catkin_ws/src/beginner_tutorials</nowiki> | <nowiki>cd ~/catkin_ws/src/beginner_tutorials</nowiki> | ||
| + | Note: If you have a ~/catkin_ws/beginner_tutorials folder: | ||
| − | 2) Create the file talker.cpp: | + | '''All changes that are done to the ~/catkin_ws/src/beginner_tutorials MUST be completed for ~/catkin_ws/beginner_tutorials as well.''' |
| + | |||
| + | 2) In ~/catkin_ws/beginner_tutorials, remove all folders and files. This can be done manually using Home Folder. | ||
| + | |||
| + | 3) Run: | ||
| + | <nowiki> | ||
| + | cd ~/catkin_ws | ||
| + | catkin_create_pkg beginner_tutorials std_msgs rospy roscpp</nowiki> | ||
| + | If errors such as "File already exist" show up, delete those files from ~/catkin_ws/src/beginner_tutorials | ||
| + | |||
| + | '''Writing the Publisher Node''' | ||
| + | |||
| + | 1) Create the file talker.cpp: | ||
<nowiki>gedit src/talker.cpp</nowiki> | <nowiki>gedit src/talker.cpp</nowiki> | ||
| − | + | 2) In the gedit editor, paste all from [https://raw.githubusercontent.com/ros/ros_tutorials/groovy-devel/roscpp_tutorials/talker/talker.cpp this link]. | |
Save the file and close the editor. For information on what is inside this file, see [http://wiki.ros.org/ROS/Tutorials/WritingPublisherSubscriber%28c%2B%2B%29#roscpp_tutorials.2BAC8-Tutorials.2BAC8-WritingPublisherSubscriber.The_Code_Explained this link]. In a nutshell, it initializes the ROS system, advertise what we are doing, and finally loop what we are doing. | Save the file and close the editor. For information on what is inside this file, see [http://wiki.ros.org/ROS/Tutorials/WritingPublisherSubscriber%28c%2B%2B%29#roscpp_tutorials.2BAC8-Tutorials.2BAC8-WritingPublisherSubscriber.The_Code_Explained this link]. In a nutshell, it initializes the ROS system, advertise what we are doing, and finally loop what we are doing. | ||
| Line 23: | Line 35: | ||
'''Building Nodes''' | '''Building Nodes''' | ||
| + | 1) Run: | ||
| + | <nowiki>catkin_create_pkg beginner_tutorials std_msgs rospy roscpp</nowiki> | ||
| + | This creates a CMakeLists.txt file and a Package.xml file. If there are errors such as "File does not exist", likely the cpp files created above need to be in the both of the beginner_tutorials folder. | ||
| + | |||
| + | 2) Edit the CMakeList.txt file (this step should be just the one folder): | ||
| + | <nowiki>gedit beginner_tutorials/CMakeLists.txt</nowiki> | ||
| + | Add the following to the end of the file: | ||
| + | <nowiki> | ||
| + | include_directories(include ${catkin_INCLUDE_DIRS}) | ||
| + | |||
| + | add_executable(talker src/talker.cpp) | ||
| + | target_link_libraries(talker ${catkin_LIBRARIES}) | ||
| + | add_dependencies(talker beginner_tutorials_generate_messages_cpp) | ||
| + | |||
| + | add_executable(listener src/listener.cpp) | ||
| + | target_link_libraries(listener ${catkin_LIBRARIES}) | ||
| + | add_dependencies(listener beginner_tutorials_generate_messages_cpp)</nowiki> | ||
| + | |||
| + | For a completely clean file, you can view the entire CMakeLists.txt file [https://raw.githubusercontent.com/ros/catkin_tutorials/master/create_package_pubsub/catkin_ws/src/beginner_tutorials/CMakeLists.txt here] | ||
| + | |||
| + | Save the file and close the editor. This should create a talker and listener files in your devel folder. | ||
| + | |||
| + | 3) Navigate to your catkin workspace: | ||
| + | <nowiki>cd ~/catkin_ws</nowiki> | ||
| + | |||
| + | 4) And make the catkin: | ||
| + | <nowiki>catkin_make</nowiki> | ||
Latest revision as of 10:35, 22 October 2014
Writing a Simple Publisher and Subscriber (C++)
1) In a terminal, move to your beginner_tutorials folder:
cd ~/catkin_ws/src/beginner_tutorials
Note: If you have a ~/catkin_ws/beginner_tutorials folder:
All changes that are done to the ~/catkin_ws/src/beginner_tutorials MUST be completed for ~/catkin_ws/beginner_tutorials as well.
2) In ~/catkin_ws/beginner_tutorials, remove all folders and files. This can be done manually using Home Folder.
3) Run:
cd ~/catkin_ws catkin_create_pkg beginner_tutorials std_msgs rospy roscpp
If errors such as "File already exist" show up, delete those files from ~/catkin_ws/src/beginner_tutorials
Writing the Publisher Node
1) Create the file talker.cpp:
gedit src/talker.cpp
2) In the gedit editor, paste all from this link. Save the file and close the editor. For information on what is inside this file, see this link. In a nutshell, it initializes the ROS system, advertise what we are doing, and finally loop what we are doing.
Writing the Subscriber Node
1) In a terminal, move to your beginner_tutorials folder:
cd ~/catkin_ws/src/beginner_tutorials
2) Create the file listener.cpp:
gedit src/listener.cpp
3) In the gedit editor, paste all from this link. Save the file and close the editor. For information on what is inside this file, see this link. In a nutshell, it initializes the ROS system, subscribes to the topic 'chatter', spin (wait for messages), when message arrives call the chatterCallback() function.
Building Nodes 1) Run:
catkin_create_pkg beginner_tutorials std_msgs rospy roscpp
This creates a CMakeLists.txt file and a Package.xml file. If there are errors such as "File does not exist", likely the cpp files created above need to be in the both of the beginner_tutorials folder.
2) Edit the CMakeList.txt file (this step should be just the one folder):
gedit beginner_tutorials/CMakeLists.txt
Add the following to the end of the file:
include_directories(include ${catkin_INCLUDE_DIRS})
add_executable(talker src/talker.cpp)
target_link_libraries(talker ${catkin_LIBRARIES})
add_dependencies(talker beginner_tutorials_generate_messages_cpp)
add_executable(listener src/listener.cpp)
target_link_libraries(listener ${catkin_LIBRARIES})
add_dependencies(listener beginner_tutorials_generate_messages_cpp)
For a completely clean file, you can view the entire CMakeLists.txt file here
Save the file and close the editor. This should create a talker and listener files in your devel folder.
3) Navigate to your catkin workspace:
cd ~/catkin_ws
4) And make the catkin:
catkin_make
