这是我在这里的第一个问题！当我试图编译我的ROS时，我面临着一个我无法理解的问题。我不是ROS的专家用户(我希望到目前为止(，我才刚刚开始了解这个系统。我在Ubuntu上有ROS Kinetic。我在c++中编写了最简单的ROS节点，只是节点的init包括"；ros/ros.h"；如这里的文档所示：http://wiki.ros.org/roscpp_tutorials/Tutorials/WritingPublisherSubscriber#CA-56e52a9f29027036和74aeea6375a15de4f70e_2
这是我的代码：只有两个文件，mypub.cpp和mysub.cpp。
// src/mypub.cpp
#include "ros/ros.h"
int main( int argc, char** argv )
{
ros::init( argc, argv, "my_publisher" );
ros::NodeHandle n;
return 0;
}
// src/mysub.cpp
#include "ros/ros.h"
int main( int argc, char** argv )
{
ros::init( argc, argv, "my_subscriber" );
ros::NodeHandle n;
return 0;
}
这是我的CMakeList.txt:
cmake_minimum_required(VERSION 3.0.2)
project(pubsub)
## 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 COMPONENTS
roscpp
std_msgs
)
## 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 pubsub
# CATKIN_DEPENDS roscpp std_msgs/String
# 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/${PROJECT_NAME}/pubsub.cpp
# )
## Add cmake target dependencies of the library
## as an example, code may need to be generated before libraries
## either from message generation or dynamic reconfigure
# add_dependencies(${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/pubsub_node.cpp)
add_executable(my_publisher src/mypub.cpp)
add_executable(my_subscriber src/mysub.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}
# )
target_link_libraries( my_publisher ${CATKIN_LIBRARIES} )
target_link_libraries( my_subscriber ${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_pubsub.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)
一切似乎都是正确的。。。但是当我启动catkin_make时，编译器会打印以下内容：
Base path: /home/rr/ROSwork/ROStest
Source space: /home/rr/ROSwork/ROStest/src
Build space: /home/rr/ROSwork/ROStest/build
Devel space: /home/rr/ROSwork/ROStest/devel
Install space: /home/rr/ROSwork/ROStest/install
####
#### Running command: "make cmake_check_build_system" in "/home/rr/ROSwork/ROStest/build"
####
####
#### Running command: "make -j2 -l2" in "/home/rr/ROSwork/ROStest/build"
####
Scanning dependencies of target my_publisher
Scanning dependencies of target my_subscriber
[ 25%] Building CXX object pubsub/CMakeFiles/my_publisher.dir/src/mypub.cpp.o
[ 50%] Building CXX object pubsub/CMakeFiles/my_subscriber.dir/src/mysub.cpp.o
[ 75%] Linking CXX executable /home/rr/ROSwork/ROStest/devel/lib/pubsub/my_subscriber
[100%] Linking CXX executable /home/rr/ROSwork/ROStest/devel/lib/pubsub/my_publisher
CMakeFiles/my_subscriber.dir/src/mysub.cpp.o: In function `main':
mysub.cpp:(.text+0x70): undefined reference to `ros::init(int&, char**, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned int)'
mysub.cpp:(.text+0xcc): undefined reference to `ros::NodeHandle::NodeHandle(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > const&)'
mysub.cpp:(.text+0xfe): undefined reference to `ros::NodeHandle::~NodeHandle()'
mysub.cpp:(.text+0x16f): undefined reference to `ros::NodeHandle::~NodeHandle()'
mysub.cpp:(.text+0x1a0): undefined reference to `ros::NodeHandle::~NodeHandle()'
collect2: error: ld returned 1 exit status
pubsub/CMakeFiles/my_subscriber.dir/build.make:94: recipe for target '/home/rr/ROSwork/ROStest/devel/lib/pubsub/my_subscriber' failed
make[2]: *** [/home/rr/ROSwork/ROStest/devel/lib/pubsub/my_subscriber] Error 1
CMakeFiles/Makefile2:946: recipe for target 'pubsub/CMakeFiles/my_subscriber.dir/all' failed
make[1]: *** [pubsub/CMakeFiles/my_subscriber.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....
CMakeFiles/my_publisher.dir/src/mypub.cpp.o: In function `main':
mypub.cpp:(.text+0x70): undefined reference to `ros::init(int&, char**, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, unsigned int)'
mypub.cpp:(.text+0xcc): undefined reference to `ros::NodeHandle::NodeHandle(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > const&)'
mypub.cpp:(.text+0xfe): undefined reference to `ros::NodeHandle::~NodeHandle()'
mypub.cpp:(.text+0x16f): undefined reference to `ros::NodeHandle::~NodeHandle()'
mypub.cpp:(.text+0x1a0): undefined reference to `ros::NodeHandle::~NodeHandle()'
collect2: error: ld returned 1 exit status
pubsub/CMakeFiles/my_publisher.dir/build.make:94: recipe for target '/home/rr/ROSwork/ROStest/devel/lib/pubsub/my_publisher' failed
make[2]: *** [/home/rr/ROSwork/ROStest/devel/lib/pubsub/my_publisher] Error 1
CMakeFiles/Makefile2:909: recipe for target 'pubsub/CMakeFiles/my_publisher.dir/all' failed
make[1]: *** [pubsub/CMakeFiles/my_publisher.dir/all] Error 2
Makefile:138: recipe for target 'all' failed
make: *** [all] Error 2
Invoking "make -j2 -l2" failed
我无法理解这个问题，这很令人沮丧，因为我觉得一切都是正确的。也许我的ROS环境设置不正确。我寻找解决方案，但我看到的所有代码都谈到了更复杂的情况。请帮帮我！
谢谢！：(
问题就在这里：
target_link_libraries(my_publisher$｛CATKIN_BRAries｝(target_link_libraries(my_subscriber$｛CATKIN_BRARIES｝(
它是"；catkin_；而不是"；CATKIN_BRARIES"。。。