0. 前言

在 ROS 中,节点的编写语言通常只有 C++ 和 Python,C++ 需要编译后才能运行,Python 则无需编译。

我们知道 Linux 平台编译 C++ 文件,需要编译器和链接器,其中编译器是将源代码编译成目标代码,链接器是将目标代码链接到可执行文件。若是编译单个文件,用 g++ 即可;若是编译一个 C++ 工程,则需要批处理编译工具,如 make,通过设定规则文件 makefile 调用 g++ 等编译工具进行批量编译。但 makefile 的编写十分复杂,便诞生了 CMake,通过编写简单的 CMakeLists.txt 规则文件,就能自动生成 makefile 文件,并且 CMake 是跨平台的,十分强大。可参考之前的博客:

ROS 的编译器便是 CMake,为了更加人性化,ROS 在 CMake 基础上封装了 catkin 命令,用 cmake 命令创建功能包时,会自动生成 CMakeList.txt 文件,已配置了多数编译选项,且包含详细的注释,只需稍作修改便可编译自己的文件。

而 package.xml 文件是描述功能包清单的文件,包括功能包的名称、版本号、作者信息、许可信息、编译依赖和运行依赖等。

我们在用 catkin_create_pkg 命令创建功能包时,是会自动生成 CMakeLists.txt 和 package.xml 文件的。

举例:

# 创建工作空间
mkdir -p ~/catkin_ws/src
cd ~/catkin_ws/src

# 注:std_msgs rospy roscpp 为创建功能时指定的依赖
# 也可以先不指定,后面在 CMakeLists.txt 和 package.xml 中手动添加
catkin_create_pkg test std_msgs rospy roscpp

# 查看一下在 ~/catkin_ws/src 目录下自动生成了哪些文件夹和文件
tree

下面看下 CMakeLists.txt 文件和 package.xml 文件各有哪些内容,需要自己改动哪些地方。

1. CMakeLists.txt 文件

常用的编译配置项如下:

(1)include_directories

  • 用于设置头文件的相对路径
  • 全局路径默认为功能包所在目录,功能包的头文件一般放在功能包根目录下的 include 文件夹,所以需要此处添加此文件夹
  • 还包含 catkin 编译器默认的其他头文件路径,如:ROS 默认安装路径、Linux 系统路径等

(2)add_exectuable

  • 用于设置需要编译的代码和可执行文件
  • 第一个参数为期望生成的可执行文件(节点)名称
  • 后面的参数为参与编译的源文件(.cpp),若需要多个代码文件,可依次列出,空格分隔

(3)target_link_libraries

  • 用于设置链接库
  • 有些功能需要使用系统或第三方库函数,通过该选项可以配置执行文件链接的库文件
  • 第一个参数与 add_exectuable 相同,为可执行文件(节点)名称
  • 后面的参数为需要链接的库,依次列出,空格分隔

(4)add_dependencies

  • 用于设置依赖
  • 有时候需要自定义消息类型,消息类型会在编译过程中产生相应语言的代码。若编译的可执行文件依赖这些动态生成的代码,则需要添加 ${PROJECT_NAME}_generate_messages_cpp 配置

(5)自定义数据类型:消息 msg、服务 srv、动作 action

  • find_package(catkin REQUIRE COMPONENTS message_generation)
  • catkin_package(CATKIN_DEPENDS message_runtime)
  • add_message_files(FILES xxx.msg)
  • add_service_files(FILES xxx.srv)
  • add_action_files(FILES xxx.action)
  • generate_messages(DEPENDENCIES std_msgs)

模板:

cmake_minimum_required(VERSION 2.8.3)
project(test)

## 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
  rospy
  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
# )

################################################
## 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 test
#  CATKIN_DEPENDS roscpp rospy std_msgs
#  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}/test.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/test_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
# install(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_test.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)

2. package.xml 文件

  • <build_depend></build_depend> 标签定义了功能包中代码编译时所依赖的其他功能包
  • <exec_depend></exec_depend> 标签定义了功能包中可执行程序运行时所依赖的其他功能包
  • 自定义数据类型:话题消息 msg、服务数据 srv,需添加
<build_depend>message_generation</build_depend>
<exec_depend>message_runtime</exec_depend>

模板:

<?xml version="1.0"?>
<package format="2">
  <name>test</name>
  <version>0.0.0</version>
  <description>The test package</description>

  <!-- One maintainer tag required, multiple allowed, one person per tag -->
  <!-- Example:  -->
  <!-- <maintainer email="jane.doe@example.com">Jane Doe</maintainer> -->
  <maintainer email="lab212@todo.todo">lab212</maintainer>


  <!-- One license tag required, multiple allowed, one license per tag -->
  <!-- Commonly used license strings: -->
  <!--   BSD, MIT, Boost Software License, GPLv2, GPLv3, LGPLv2.1, LGPLv3 -->
  <license>TODO</license>


  <!-- Url tags are optional, but multiple are allowed, one per tag -->
  <!-- Optional attribute type can be: website, bugtracker, or repository -->
  <!-- Example: -->
  <!-- <url type="website">http://wiki.ros.org/test</url> -->


  <!-- Author tags are optional, multiple are allowed, one per tag -->
  <!-- Authors do not have to be maintainers, but could be -->
  <!-- Example: -->
  <!-- <author email="jane.doe@example.com">Jane Doe</author> -->


  <!-- The *depend tags are used to specify dependencies -->
  <!-- Dependencies can be catkin packages or system dependencies -->
  <!-- Examples: -->
  <!-- Use depend as a shortcut for packages that are both build and exec dependencies -->
  <!--   <depend>roscpp</depend> -->
  <!--   Note that this is equivalent to the following: -->
  <!--   <build_depend>roscpp</build_depend> -->
  <!--   <exec_depend>roscpp</exec_depend> -->
  <!-- Use build_depend for packages you need at compile time: -->
  <!--   <build_depend>message_generation</build_depend> -->
  <!-- Use build_export_depend for packages you need in order to build against this package: -->
  <!--   <build_export_depend>message_generation</build_export_depend> -->
  <!-- Use buildtool_depend for build tool packages: -->
  <!--   <buildtool_depend>catkin</buildtool_depend> -->
  <!-- Use exec_depend for packages you need at runtime: -->
  <!--   <exec_depend>message_runtime</exec_depend> -->
  <!-- Use test_depend for packages you need only for testing: -->
  <!--   <test_depend>gtest</test_depend> -->
  <!-- Use doc_depend for packages you need only for building documentation: -->
  <!--   <doc_depend>doxygen</doc_depend> -->

  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>roscpp</build_depend>
  <build_depend>rospy</build_depend>
  <build_depend>std_msgs</build_depend>
  <build_export_depend>roscpp</build_export_depend>
  <build_export_depend>rospy</build_export_depend>
  <build_export_depend>std_msgs</build_export_depend>
  <exec_depend>roscpp</exec_depend>
  <exec_depend>rospy</exec_depend>
  <exec_depend>std_msgs</exec_depend>


  <!-- The export tag contains other, unspecified, tags -->
  <export>
    <!-- Other tools can request additional information be placed here -->

  </export>
</package>