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对 ros::init 的未定义引用 - 简单案例

如何解决对 ros::init 的未定义引用 - 简单案例

这是我在这里的第一个问题! 我在尝试编译我的 ROS 时遇到了一个我无法理解的问题。我不是 ROS 的专家用户(到目前为止,我希望如此),我才刚刚开始了解该系统。我在 Ubuntu 上安装了 ROS Kinetic。我用 C++ 编写了最简单的 ROS 节点,只是节点的初始化,包括“ros/ros.h”,如此处的文档所示:http://wiki.ros.org/roscpp_tutorials/Tutorials/WritingPublisherSubscriber#CA-56e552a9f29027036adb74aeea6375a15de4f70e_2

这是我的代码:只有两个文件mypub.cppmysub.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,"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)

一切似乎都正确......但是当我启动catkin_make时,编译器会打印:

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::map<std::__cxx11::basic_string<char,std::allocator<char> >,std::less<std::__cxx11::basic_string<char,std::allocator<char> > >,std::allocator<std::pair<std::__cxx11::basic_string<char,std::allocator<char> > const,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&,unsigned int)'
mypub.cpp:(.text+0xcc): undefined reference to `ros::NodeHandle::NodeHandle(std::__cxx11::basic_string<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,因为在我看来一切都是正确的。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在谈论更复杂的情况。请帮帮我!

谢谢! :)

解决方法

问题出在这里:

target_link_libraries( my_publisher ${CATKIN_LIBRARIES} ) target_link_libraries( my_subscriber ${CATKIN_LIBRARIES} )

它是“catkin_LIBRARIES”而不是“CATKIN_LIBRARIES”......

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