1.自定义msg

这里的自定义msg和python的其实是一样的：
首先在src目录下

catkin_create_pkg car_interfaces rospy roscpp std_msgs message_runtime message_generation

然后新建一个msg文件夹，然后建立相应的msg文件，接着就可以修改编译所需的东西了
定义的msg就自己想怎么写就怎么写吧
首先是CMakeLists.txt：

cmake_minimum_required(VERSION 3.0.2)
project(car_interfaces)## 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 COMPONENTSmessage_generationmessage_runtimeroscpprospystd_msgs
)add_message_files(FILESGlobalPathPlanningInterface.msgGpsImuInterface.msg
)generate_messages(DEPENDENCIESstd_msgs
)catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES car_interfacesCATKIN_DEPENDS message_generation message_runtime roscpp rospy std_msgs
#  DEPENDS system_lib
)include_directories(
# include${catkin_INCLUDE_DIRS}
)

然后是package.xml：

<?xml version="1.0"?>
<package format="2"><name>car_interfaces</name><version>0.0.0</version><description>The car_interfaces package</description><!-- One maintainer tag required, multiple allowed, one person per tag --><!-- Example:  --><!-- <maintainer email="jane.doe@example.com">Jane Doe</maintainer> --><maintainer email="cyun@todo.todo">cyun</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/car_interfaces</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>message_generation</build_depend><build_depend>message_runtime</build_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>message_runtime</exec_depend><exec_depend>message_generation</exec_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>

基本上就按照这个结构来写，然后正常编译就可以了

2.ros c++联合编程语言

#include<ros/ros.h>
#include<car_interfaces/GlobalPathPlanningInterface.h>
// #include<car_interfaces/GpsImuInterface.h>int main(int argc, char *argv[])
{   ros::init(argc, argv, "plan_node") ;ros::NodeHandle nh;ros::Publisher pub = nh.advertise<car_interfaces::GlobalPathPlanningInterface>("global",10);// ros::Publisher pub2 = nh.advertise<car_interfaces::GpsImuInterface>("gps",10);ros::Rate loop_rate(10);while (ros::ok()){ ROS_INFO("SUCCESS");car_interfaces::GlobalPathPlanningInterface msg1;// car_interfaces::GpsImuInterface msg2;msg1.timestamp = 1000; msg1.process_time = 230;// msg2.gps_time = 10000;pub.publish(msg1);// pub2.publish(msg2);ros::spinOnce(); loop_rate.sleep();} return 0;}

这个是发布的部分，注意思路，将接收的全部开成一个线程，将发布的话题每个都写成一个线程。
然后是发布的数据

#include <ros/ros.h>
#include <car_interfaces/GlobalPathPlanningInterface.h>
#include <car_interfaces/GpsImuInterface.h>// 回调函数
void plan_message_callback(const car_interfaces::GlobalPathPlanningInterface::ConstPtr& msg)
{double timestamp = msg->timestamp;float process_time = msg->process_time;ROS_INFO("Received plan");
}int main(int argc, char* argv[])
{ros::init(argc, argv, "plan_sub");ros::NodeHandle nh;ros::Publisher pub = nh.advertise<car_interfaces::GpsImuInterface>("pub2", 10);ros::Subscriber sub = nh.subscribe("global", 10, plan_message_callback);ros::Rate loop_rate(10);while (ros::ok()){car_interfaces::GpsImuInterface msg;msg.gps_time = 10000;pub.publish(msg);ros::spinOnce();loop_rate.sleep();}return 0;
}

然后修改相应的CMameLists.txt：

cmake_minimum_required(VERSION 3.0.2)
project(planning)## 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 COMPONENTScar_interfacesroscpprospystd_msgs
)catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES planning
#  CATKIN_DEPENDS car_interfaces roscpp rospy std_msgs
#  DEPENDS system_lib
)## Specify additional locations of header files
## Your package locations should be listed before other locations
include_directories(
# include${catkin_INCLUDE_DIRS}
)add_executable(${PROJECT_NAME}_node src/plan.cpp)
add_executable(plan_sub_node src/plan_sub.cpp)add_dependencies(${PROJECT_NAME}_node car_interfaces_generate_messages_cpp)# Specify libraries to link a library or executable target against
target_link_libraries(${PROJECT_NAME}_node${catkin_LIBRARIES}
)target_link_libraries(plan_sub_node${catkin_LIBRARIES}
)

package.xml：

<?xml version="1.0"?>
<package format="2"><name>planning</name><version>0.0.0</version><description>The planning package</description><!-- One maintainer tag required, multiple allowed, one person per tag --><!-- Example:  --><!-- <maintainer email="jane.doe@example.com">Jane Doe</maintainer> --><maintainer email="cyun@todo.todo">cyun</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/planning</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>car_interfaces</build_depend><build_depend>roscpp</build_depend><build_depend>rospy</build_depend><build_depend>std_msgs</build_depend><build_export_depend>car_interfaces</build_export_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>car_interfaces</exec_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>

以上完成后就可以建立c++的ros通信了

后面要做的事：
1.把这个结构给完全理解并深入掌握
2.按照相应的规则重新写线程