[ROS] (02) Create & compile ROS package Package

  文章只是个人学习过程中学习笔记,主要参考ROS教程¹.

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先阅读这篇文章：
[ROS]（01）创建ROS工作空间：https://blog.csdn.net/CynalFly/article/details/125617470

1. 概述

  packages是在ROSArrangement and organization of the main unit,是在ROSThe smallest unit that can be set up and share.

在编译时,catkinBuild system will recursive search and editsrcEach file directorypackage.It can be a fewpackage放在同一个文件夹下.

2. package结构

  ROS软件包packageFollow a common structure,如下图所示.packageDirectory of the file name is recklessly cast.其中只有 CMakeLists.txt 和 package.xml 是必需项,Everything else is determined according to the demand of.

• CMakeLists.txt:：包含CMake构建文件,定义package的包名、源文件、依赖、The target file compiling rules such as;
• package.xml：包含了 package Describe the relationship between information and rely on,And record version、维护者、Licenses and other relevant software package of information;
• scripts：可执行脚本,Python脚本(.py),shell脚本(.sh);
• src：源文件C++
• include：C++头文件
• msg：Store the message file（.msg）
• srv：存放服务文件（.srv）
• action：Where action files（.action）
• launch：存放launch文件（.launch或.xml）,可一次运行多个节点;
• config：配置信息;

3. 创建软件包Package

  创建一个package,需要在ROS（catkin）工作空间中的src文件夹目录下,使用catkin_create_pkg脚本来创建.命令格式：
catkin_create_pkg <package_name> [depend1] [depend2] [depend3][...][dependn]

package_name：包名,To create the name of the software（必须）
depend:依赖,Other packages depend on,例如std_msgs、rospy、roscpp等（非必须）

  举例：创建一个名为beginner_tutorials的新软件包,软件包依赖std_msgs、rospy、roscpp.在终端中输入如下命令：

cd ~/catkin_ws/src
catkin_create_pkg beginner_tutorials std_msgs rospy roscpp

std_msgs：是ROSGive us a defined some standard data structure.
rospy：是ROSTo provide us with a series ofpython接口.
roscpp：是ROS给我们提供的c++的编程接口.

  成功后,将在src目录下创建一个名为beginner_tutorials的文件夹,在该文件夹下的package.xml文件和一个CMakeLists.txtThe file has been fill in.

4. 编译软件包Package

  编译（build）一个package,需要在ROS（catkin）工作空间目录下,使用catkin_make编译.在终端中输入如下命令：

cd ~/catkin_ws
catkin_make
catkin_make install  # （可选）

  The above command can one-time compilingROSWorking space all packagespackages.If want to compile a specific packages,命令格式：

catkin_make -DCATKIN_WHITELIST_PACKAGES="package1;package2"

• package1 和 package2 为包名
• Use this command after,在同一窗口下,直接使用catkin_makeOr will only compile a package

  举例：编译软件包packagebeginner_tutorials.在终端中输入如下命令：

catkin_make -DCATKIN_WHITELIST_PACKAGES=”beginner_tutorials”

  If you want to restore to compile all the packages,在终端中输入如下命令：

catkin_make -DCATKIN_WHITELIST_PACKAGES=""

5. package的命令行工具

  随着ROSIncreasing the package,中使用Linux内置的命令行工具（如cd、ls等）When switching directories and search a file,Can be very complicated.因此ROSProvides a special command line tools（Command-line Tolls）来简化这些操作.
  rospack：
  rospackCommand can get packagepackage的有关信息.常见的命令包括：

• rospack find [package] ：返回package的绝对路径

• rospack depends1 [package]：返回一个packageThe level of dependence on list
• rospack depends [package]：返回一个packageAll of the direct and indirect rely on list
• rospack depends-on [package]：返回依赖于指定package的所有packages list

• rospack list | grep <package-name> <package-dir>：Returns the package or packages include pathpackage list

上述命令的package可以缺省,Is considered in the current directory of all rely on;But this has a premise is the current directory containspackage.xml.If does not include the return information：[rospack] Error：no package given.

  roscd：
  roscd可以直接切换到ROS软件包,它和Linux系统的cd的区别,请看：
  [ROS]roscd和cd的区别：https://blog.csdn.net/CynalFly/article/details/125519428

  rosls：
  rosls可以直接lsROS软件包的内容.用法：rosls [package].

查看ROSAll of the command line tools：http://wiki.ros.org/ROS/CommandLineTools

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1. ROS.otg. ROS教程[EB/OL]. 2020-12-22[2022-7-5].
   http://wiki.ros.org/cn/ROS/Tutorials. ︎