This article aims to help you realize simple HelloWorld in ROS.
Create a workspace named test_ws. The following operations are based on this directory. There must be a subfolder named src under this directory.
mkdir -p ~/test_ws/src
cd ~/test_ws/src
catkin_init_workspaceAfter the workspace is initialized, a top-level CMakeLists.txt will be generated in the src directory.
Initialize function package
Use the catkin_create_pkg command to create the required function package.
Here, we create a helloworld package. Note that the following commands need to be executed in the src directory:
cd src
catkin_create_pkg helloworldFinally, the necessary files in the helloworld function package will be automatically generated, including the package description file package.xml and the catkin version of the cmake compilation script CMakeLists.txt file.
When creating the helloworld package in the previous step, the source file specified in CMakeList.txt is src/helloworld_node.cpp by default, and the header file path specified is include. Therefore, in order to avoid trouble, we will follow this specification and create a corresponding source file.
mkdir src
mkdir include
gedit src/helloworld_node.cppsource file:
//helloworld_node.cpp
#include <iostream>
int main(int argc, char *argv[])
{
printf("hello world !\n");
return 0;
}So far, we have completed most of the work. Next, we need to modify the CMakeLists.txt file in the function package to finally compile the helloworld_node.cpp file into an executable program.
Modify CMakeLists.txt in the function package
Cancel the comments on lines 5, 115, 116, 132, 138, 142 and 145~147. The CMakeLists.txt file is modified as follows:
cmake_minimum_required(VERSION 3.0.2)
project(helloworld)
## Compile as C++11, supported in ROS Kinetic and newer
add_compile_options(-std=c++11)
## Find catkin macros and libraries
## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)
## is used, also find other catkin packages
find_package(catkin REQUIRED)
## System dependencies are found with CMake's conventions
# find_package(Boost REQUIRED COMPONENTS system)
## Uncomment this if the package has a setup.py. This macro ensures
## modules and global scripts declared therein get installed
## See http://ros.org/doc/api/catkin/html/user_guide/setup_dot_py.html
# catkin_python_setup()
################################################
## Declare ROS messages, services and actions ##
################################################
## To declare and build messages, services or actions from within this
## package, follow these steps:
## * Let MSG_DEP_SET be the set of packages whose message types you use in
## your messages/services/actions (e.g. std_msgs, actionlib_msgs, ...).
## * In the file package.xml:
## * add a build_depend tag for "message_generation"
## * add a build_depend and a exec_depend tag for each package in MSG_DEP_SET
## * If MSG_DEP_SET isn't empty the following dependency has been pulled in
## but can be declared for certainty nonetheless:
## * add a exec_depend tag for "message_runtime"
## * In this file (CMakeLists.txt):
## * add "message_generation" and every package in MSG_DEP_SET to
## find_package(catkin REQUIRED COMPONENTS ...)
## * add "message_runtime" and every package in MSG_DEP_SET to
## catkin_package(CATKIN_DEPENDS ...)
## * uncomment the add_*_files sections below as needed
## and list every .msg/.srv/.action file to be processed
## * uncomment the generate_messages entry below
## * add every package in MSG_DEP_SET to generate_messages(DEPENDENCIES ...)
## Generate messages in the 'msg' folder
# add_message_files(
# FILES
# Message1.msg
# Message2.msg
# )
## Generate services in the 'srv' folder
# add_service_files(
# FILES
# Service1.srv
# Service2.srv
# )
## Generate actions in the 'action' folder
# add_action_files(
# FILES
# Action1.action
# Action2.action
# )
## Generate added messages and services with any dependencies listed here
# generate_messages(
# DEPENDENCIES
# std_msgs # Or other packages containing msgs
# )
################################################
## Declare ROS dynamic reconfigure parameters ##
################################################
## To declare and build dynamic reconfigure parameters within this
## package, follow these steps:
## * In the file package.xml:
## * add a build_depend and a exec_depend tag for "dynamic_reconfigure"
## * In this file (CMakeLists.txt):
## * add "dynamic_reconfigure" to
## find_package(catkin REQUIRED COMPONENTS ...)
## * uncomment the "generate_dynamic_reconfigure_options" section below
## and list every .cfg file to be processed
## Generate dynamic reconfigure parameters in the 'cfg' folder
# generate_dynamic_reconfigure_options(
# cfg/DynReconf1.cfg
# cfg/DynReconf2.cfg
# )
###################################
## catkin specific configuration ##
###################################
## The catkin_package macro generates cmake config files for your package
## Declare things to be passed to dependent projects
## INCLUDE_DIRS: uncomment this if your package contains header files
## LIBRARIES: libraries you create in this project that dependent projects also need
## CATKIN_DEPENDS: catkin_packages dependent projects also need
## DEPENDS: system dependencies of this project that dependent projects also need
catkin_package(
# INCLUDE_DIRS include
# LIBRARIES helloworld
# CATKIN_DEPENDS other_catkin_pkg
# DEPENDS system_lib
)
###########
## Build ##
###########
## Specify additional locations of header files
## Your package locations should be listed before other locations
include_directories(
include
${catkin_INCLUDE_DIRS}
)
## Declare a C++ library
# add_library(${PROJECT_NAME}
# src/${PROJECT_NAME}/helloworld.cpp
# )
## Add cmake target dependencies of the library
## as an example, code may need to be generated before libraries
## either from message generation or dynamic reconfigure
# add_dependencies(${PROJECT_NAME} ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
## Declare a C++ executable
## With catkin_make all packages are built within a single CMake context
## The recommended prefix ensures that target names across packages don't collide
add_executable(${PROJECT_NAME}_node src/helloworld_node.cpp)
## Rename C++ executable without prefix
## The above recommended prefix causes long target names, the following renames the
## target back to the shorter version for ease of user use
## e.g. "rosrun someones_pkg node" instead of "rosrun someones_pkg someones_pkg_node"
set_target_properties(${PROJECT_NAME}_node PROPERTIES OUTPUT_NAME node PREFIX "")
## Add cmake target dependencies of the executable
## same as for the library above
add_dependencies(${PROJECT_NAME}_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
## Specify libraries to link a library or executable target against
target_link_libraries(${PROJECT_NAME}_node
${catkin_LIBRARIES}
)
#############
## Install ##
#############
# all install targets should use catkin DESTINATION variables
# See http://ros.org/doc/api/catkin/html/adv_user_guide/variables.html
## Mark executable scripts (Python etc.) for installation
## in contrast to setup.py, you can choose the destination
# catkin_install_python(PROGRAMS
# scripts/my_python_script
# DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
# )
## Mark executables for installation
## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_executables.html
# install(TARGETS ${PROJECT_NAME}_node
# RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
# )
## Mark libraries for installation
## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_libraries.html
# install(TARGETS ${PROJECT_NAME}
# ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
# LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
# RUNTIME DESTINATION ${CATKIN_GLOBAL_BIN_DESTINATION}
# )
## Mark cpp header files for installation
# install(DIRECTORY include/${PROJECT_NAME}/
# DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION}
# FILES_MATCHING PATTERN "*.h"
# PATTERN ".svn" EXCLUDE
# )
## Mark other files for installation (e.g. launch and bag files, etc.)
# install(FILES
# # myfile1
# # myfile2
# DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}
# )
#############
## Testing ##
#############
## Add gtest based cpp test target and link libraries
# catkin_add_gtest(${PROJECT_NAME}-test test/test_helloworld.cpp)
# if(TARGET ${PROJECT_NAME}-test)
# target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME})
# endif()
## Add folders to be run by python nosetests
# catkin_add_nosetests(test)After the above modifications are completed, use the catkin_make command to compile all the function packages in the workspace, finally generate the corresponding target file, and execute the following commands in the root directory of the workspace:
cd ~/test_ws/The purpose of the helloworld function pack is to print the word "hello world!" in the command window after running. In the root directory of the workspace, we need to import some necessary environment variables of ros, and then the command tool in ros can find our say_hello function package, and then we can use the rosrun command to run the executable program in the say_hello function package.
source devel/setup.bash
rosrun helloworld nodeAfter compilation, the directory structure in the workspace:
tree -L 2.
├── build
│ ├── atomic_configure
│ ├── catkin
│ ├── catkin_generated
│ ├── CATKIN_IGNORE
│ ├── catkin_make.cache
│ ├── CMakeCache.txt
│ ├── CMakeFiles
│ ├── cmake_install.cmake
│ ├── CTestConfiguration.ini
│ ├── CTestCustom.cmake
│ ├── CTestTestfile.cmake
│ ├── gtest
│ ├── helloworld
│ ├── Makefile
│ └── test_results
├── devel
│ ├── cmake.lock
│ ├── env.sh
│ ├── lib
│ ├── local_setup.bash
│ ├── local_setup.sh
│ ├── local_setup.zsh
│ ├── setup.bash
│ ├── setup.sh
│ ├── _setup_util.py
│ ├── setup.zsh
│ └── share
└── src
├── CMakeLists.txt -> /opt/ros/melodic/share/catkin/cmake/toplevel.cmake
└── helloworld
13 directories, 18 filesThis is the end of this article. If you like it, don't forget to pay attention to me and leave your likes or forks. Your encouragement is my biggest motivation, thank you.