ROS2 的包必须在 src 文件夹下，使用下面的命令创建一个包，并设置相关的依赖
ros2 pkg create my_package --dependencies rclcpp std_msgs
可以打开包内的 package.xml ，查看 depend 有哪些依赖
#include "rclcpp/rclcpp.hpp"
int main(int argc,char *argv[])
{rclcpp::init(argc,argv);auto node = rclcpp::Node::make_shared("simple_node");rclcpp::spin(node);rclcpp::shutdown();return 0;
}
rclcpp::Node包含了很多等价的别名以及静态方法，SharedPtr是std::shared ptr<rclcpp::Node>的别名，而make_shared是它的静态方法。该行代码创建了一个名字叫simple_node的节点，在程序中以node表示该节点spin可以阻止代码的执行，防止他立即终止shutdown管理节点的关闭
接下来，来看看CMake文件
cmake_minimum_required(VERSION 3.8)
project(my_package)if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")add_compile_options(-Wall -Wextra -Wpedantic)
endif()# find dependencies
find_package(ament_cmake REQUIRED)
find_package(rclcpp REQUIRED)
find_package(std_msgs REQUIRED)set(dependenciesrclcpp
)add_executable(simple src/simple.cpp)
ament_target_dependencies(simple ${dependencies})install(TARGETSsimpleARCHIVE DESTINATION libLIBRARY DESTINATION libRUNTIME DESTINATION lib/${PROJECT_NAME})
if(BUILD_TESTING)find_package(ament_lint_auto REQUIRED)# the following line skips the linter which checks for copyrights# comment the line when a copyright and license is added to all source filesset(ament_cmake_copyright_FOUND TRUE)# the following line skips cpplint (only works in a git repo)# comment the line when this package is in a git repo and when# a copyright and license is added to all source filesset(ament_cmake_cpplint_FOUND TRUE)ament_lint_auto_find_test_dependencies()
endif()
ament_export_dependencies(${dependencies})
ament_package()
之后编译并运行
colcon build --symlink-install
ros2 run my_packkage simple
由于使用了 spin 因此程序并没有执行任何内容
