Messenger Class Reference

A tiny class implemented ROS like Pub/Sub messaging. More...

Public Member Functions
template<class M >
Publisher	advertise (const std::string &topic, uint32_t queue_size=0)
	Create a Publisher. More...
template<class M >
void	publish (const std::string &topic, const M &message)
	publish a message without creating a publisher More...
Subscriber	subscribe (const std::string &topic, uint32_t queue_size, SvarFunction callback)
	subscribe a topic with callback function More...
Subscriber	subscribe (const std::string &topic, SvarFunction callback, uint32_t queue_size=0)
	subscribe a topic with callback function
template<class T , class M >
Subscriber	subscribe (const std::string &topic, uint32_t queue_size, void(T::*fp)(const std::shared_ptr< M > &), T *obj)
	subscribe a topic with callback member function
template<class M >
Subscriber	subscribe (const std::string &topic, int queue_size, void(*fp)(const M &))
	subscribe a topic with callback function
template<class T , class M >
Subscriber	subscribe (const std::string &topic, uint32_t queue_size, void(T::*fp)(const M &), T *obj)
	subscribe a topic with callback member function
std::vector< Publisher >	getPublishers () const
	get all publishers
std::vector< Subscriber >	getSubscribers () const
	get all subscribers
std::string	introduction (int width=80) const
	list all publishers and subscribers
void	join (const Publisher &pub)
	Let the Publisher join this Messenger space.
void	join (const Subscriber &sub)
	Let the Subscriber join this Messenger space.
void	join (Messenger another)
	Let all publishers and subscribers left the old space.

Static Public Member Functions
static Messenger &	instance ()
static int	exec ()
	Notify and wait Subscribers to shutdown.

Detailed Description

A tiny class implemented ROS like Pub/Sub messaging.

Messenger: A light-weight, efficient, thread-safe message publish and subscribe tool similar with ROS, a popular robot operating system.

The tool has the following features:

• Header only based on c++11, no extra dependency, makes it portable.
• Thread safe and support multi-thread condition notify mode by setting the queue size.
• Able to transfer any classes efficiently, including ROS defined messages, which means it can replace ROS messagging or work with it.

// example.cpp
#include <GSLAM/core/Messenger.h>

using namespace GSLAM;

int main(int argc,char** argv)
{
    Subscriber sub=messenger.subscribe("topic_name",[](std::string msg){
        std::cerr<<"Received string msg "<<msg<<std::endl;
    });

    // publish message without creating a Publisher
    messenger.publish("topic_name","hello world!");

    Publisher pub=messenger.advertise<std::string>("topic_name");
    pub.publish("hello Messenger!");

    return 0;
}

Warning

The Subscriber will auto shutdown, please hold the Subscriber instance until you want to unsubscribe.

Member Function Documentation

static Messenger& instance ( )

static

Returns

The Messenger instance (messenger)

Publisher advertise	(	const std::string &	topic,
		uint32_t	queue_size = 0
	)

Create a Publisher.

Parameters

topic	the topic name
queue_size	when queue_size>0, messages will be sent in another thread

Returns

the Publisher created

void publish	(	const std::string &	topic,
		const M &	message
	)

publish a message without creating a publisher

Parameters

topic	the topic name
message	the message will be sent in this thread

Subscriber subscribe	(	const std::string &	topic,
		uint32_t	queue_size,
		SvarFunction	callback
	)

subscribe a topic with callback function

Parameters

topic	the topic name
queue_size	when queue_size>0, messages will be handled in a separate thread
callback	the callback function used to handle the messages