ROS服务编程：：3，创建Client

#include<cstdlib>
#include\"ros/ros.h\"
#include\"my_package/AddTwoInts.h\"
int main(int argc, char **argv)
{
    ros::init(argc, argv, \"add_two_ints_client\");
    if (argc !=3)
    {
        ROS_INFO(\"usage:add_two_ints_client X Y\");
        return 1;
    }

    ros::NodeHandle n;
    ros::ServiceClient client = n.serviceClient<my_package::AddTwoInts>(\"add_two_ints\");
    my_package::AddTwoInts srv;
    srv.request.a=atoll(argv[1]);
    srv.request.b=atoll(argv[2]);

    if (client.call(srv))
    {
        ROS_INFO(\"Sum: %ld\",(long int)srv.response.sum);
    }
    else
    {
        ROS_ERROR(\"Failed to call service add_two_ints\");
        return 1;
    }
    return 0;
}

1，创建Client

ros::ServiceClient client = n.serviceClient<my_package::AddTwoInts>(\"add_two_ints\");

创建一个名为add_two_ints的服务，指定服务类型为：my_package::AddTwoInts

2，发布服务请求

my_package::AddTwoInts srv;
    srv.request.a=atoll(argv[1]);
    srv.request.b=atoll(argv[2]);

实例化一个服务数据类型的变量，该变量包括两个成员：request和response。

    if (client.call(srv))
    {
        ROS_INFO(\"Sum: %ld\",(long int)srv.response.sum);
    }
    else
    {
        ROS_ERROR(\"Failed to call service add_two_ints\");
        return 1;
    }

进行服务调用，调用成功返回true，访问srv.response即可获取服务请求的结果。如果调用失败返回false，srv.response不可用。服务中的Client类似于话题中的Publisher，实现流程如下：

1，初始化ROS节点

2，创建一个Client实例

3，发布服务请求数据

4，等待Server处理后的应答结果

编译功能包：

编辑CMakelist.txt加入一下内容：

add_executable(service
  src/service.cpp
)
target_ _libraries(service
  ${catkin_LIBRARIES}
)
add_dependencies(service ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})


add_executable(client
  src/client.cpp
)
target_ _libraries(client
  ${catkin_LIBRARIES}
)
add_dependencies(client ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})