ros::NodeHandle成员介绍

Advertise a topic, simple version.

This call connects to the master to publicize that the node will be publishing messages on the given topic. This method returns a Publisher that allows you to publish a message on this topic.

This version of advertise is a templated convenience function, and can be used like so

使用示例：

ros::Publisher pub = handle.advertise<std_msgs::Empty>(“my_topic”, 1);

Parameters:

topic	Topic to advertise on
queue_size	Maximum number of outgoing messages to be queued for delivery to subscribers
latch	(optional) If true, the last message published on this topic will be saved and sent to new subscribers when they connect

Returns:

On success, a 
Publisher that, when it goes out of scope, will automatically release a reference on this advertisement. On failure, an empty 
Publisher.

Exceptions:

InvalidNameException

If the topic name begins with a tilde, or is an otherwise invalid graph resource name, or is an otherwise invalid graph resource name

介绍：以指定名称，队列大小发布一个topic，latch参数表示是否发送保存，可不初始化。

回调函数写法：

 void connectCallback(const ros::SingleSubscriberPublisher& pub)
     {
     // Do something
     }

 ros::Publisher pub =handle.advertise<std_msgs::Empty>("my_topic", 1, (ros::SubscriberStatusCallback)connectCallback);

2 
NodeHandle::subscribe

Subscriber ros::NodeHandle::subscribe	(	const std::string &	topic,
		uint32_t	queue_size,
		void(T::*)(M)	fp,
		T *	obj,
		const TransportHints &	transport_hints = TransportHints()
	)		[inline]

Subscribe to a topic, version for class member function with bare pointer.

This method connects to the master to register interest in a given topic. The node will automatically be connected with publishers on this topic. On each message receipt, fp is invoked and passed a shared pointer to the message received. This message should not be changed in place, as it is shared with any other subscriptions to this topic.

This version of subscribe is a convenience function for using member functions, and can be used like so:

void Foo::callback(const std_msgs::Empty::ConstPtr& message)
{
}

Foo foo_object;
ros::Subscriber sub = handle.subscribe("my_topic", 1, &Foo::callback, &foo_object);

参数
topic	Topic to subscribe to
queue_size	Number of incoming messages to queue up for processing (messages in excess of this queue capacity will be discarded).
fp	Member function pointer to call when a message has arrived
obj	Object to call fp on
transport_hints	a TransportHints structure which defines various transport-related options

参数解释：

fp 消息到达时的回调函数指针

obj 回调对象

    
    
   
   

    
    
 
     
 
      
3 NodeHandle::serviceClient
 
     
 
    
   
   

    
    
   
   

     
     
    
    
 
     
 
      
 
       
ServiceClient ros::NodeHandle::serviceClient
 
       
(
 
       
const std::string & 
 
       
service_name,
 
      
 
      
 
       
 
 
       
 
 
       
bool 
 
       
persistent = false,
 
      
 
      
 
       
 
 
       
 
 
       
const M_string & 
 
       
header_values = M_string() 
 
      
 
      
 
       
 
 
       
)
 
       
 
 
       
[inline]
 
      
 
     
 
    
    
    
   
   
    
    
   
   

     
     
    
    
Create a client for a service, version templated on two message types.
     
     
    
    
When the last handle reference of a persistent connection is cleared, the connection will automatically close.
     
     
    
    
 
     Parameters: 
     
 
      
 
       
 
        
 
         
service_name
 
         
The name of the service to connect to
 
        
 
        
 
         
persistent
 
         
Whether this connection should persist. Persistent services keep the connection to the remote host active so that subsequent calls will happen faster. In general persistent services are discouraged, as they are not as robust to node failure as non-persistent services.
 
        
 
        
 
         
header_values
 
         
Key/value pairs you'd like to send along in the connection handshake
 
        
 
       
 
      
 
     
 
    
     
     
    
    

      参数解释： 
     service_name链接到的服务的名称 
      persistent是否持续连接 
     Exceptions: 
     
 
      
 
       
 
        
 
         
InvalidNameException
 
         
If the service name begins with a tilde, or is an otherwise invalid graph resource name
 
        
 
       
 
      
 
     
 
    
    
    
   
   

4 NodeHandle::advertiseService
    
    
   
   

     
     
    
    
 
     
 
      
 
       
 ros::NodeHandle::advertiseService
 
       
(
 
       
const std::string & 
 
       
service,
 
      
 
      
 
       
 
 
       
 
 
       
bool(T::*)(MReq &, MRes &) 
 
       
srv_func,
 
      
 
      
 
       
 
 
       
 
 
       
T * 
 
       
obj 
 
      
 
      
 
       
 
 
       
)
 
       
 
 
       
[inline]
 
      
 
     
 
    
    
    
   
   
    
    
   
   

     
     
    
    
Advertise a service, version for class member function with bare pointer.
     
     
    
    
This call connects to the master to publicize that the node will be offering an RPC service with the given name.
     
     
    
    
This is a convenience function for using member functions, and can be used like so:
     
     
    
    
 
     
bool Foo::callback(std_srvs::Empty& request, std_srvs::Empty& response)
{
  return true;
}

Foo foo_object;
ros::ServiceServer service = handle.advertiseService("my_service", &Foo::callback, &foo_object);



     Parameters: 





service
Service name to advertise on


srv_func
Member function pointer to call when a message has arrived


obj
Object to call srv_func on






     Returns: 


       On success, a 

      ServiceServer that, when all copies of it go out of scope, will unadvertise this service. On failure, an empty 

      ServiceServer which can be checked with: 


bool Foo::callback(std_srvs::Empty& request, std_srvs::Empty& response)
{
  return true;
}
ros::NodeHandle nodeHandle;
Foo foo_object;
ros::ServiceServer service = nodeHandle.advertiseService("my_service", &Foo::callback, &foo_object);
if (service)  // Enter if advertised service is valid
{
...
}