id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
7724,executing signals2::signal::connect creates many copies of the connected object,pszeptycki@…,Frank Mori Hess,"I am trying to figure out where is the problem, maybe what I have implemented is incorrect or it is a bug.

When trying to connect to a signal the passed object is copied many times and the final triggered signal executes a method on a copy of the passed object.

Signal is the following type:
{{{
typedef signals2::signal<void (NotificationCenter::Notification)> Signal;
}}}
Following code (NotificationCenter creates a shared_ptr<> to the requested signals):
{{{
class NotificationReceived
{
public:
	int runCount;
	NotificationReceived()
	{
		std::cout << ""*  Receiver CREATED"" << std::endl;
		runCount = 0;
	}

	NotificationReceived(const NotificationReceived &cSource)
	{
		std::cout << ""*  Receiver COPIED"" << std::endl;
		runCount = cSource.runCount;
	}

	~NotificationReceived()
	{
		std::cout << ""*  Receiver DELETED"" << std::endl;
	}

	void Receive(NotificationCenter::Notification notif) 
	{
		std::cout << std::endl << ""Receive: Notification received: "" + notif.m_information << std::endl << std::endl;
		runCount++;
	}
};

BOOST_AUTO_TEST_CASE( test_notification_center_notify)
{
	NotificationCenter nCenter(NotificationCenter::NCT_DELAYED);
	NotificationReceived receiver;
	NotificationCenter::Signal* sig = nCenter.RegisterForNotification(NotificationCenter::Notification::NT_BROADCAST);
	sig->connect(boost::bind(&NotificationReceived::Receive, receiver, _1));


	nCenter.BroadcastNotification(NotificationCenter::Notification(NotificationCenter::Notification::NT_BROADCAST, ""Testing""));
	boost::this_thread::sleep(boost::posix_time::seconds(2));
	BOOST_REQUIRE_EQUAL(receiver.runCount, 1);
}
}}}
Has following output:
{{{
*  Receiver CREATED
- Queue empty - sleeping 500ms
*  Receiver COPIED
*  Receiver COPIED
*  Receiver COPIED
*  Receiver COPIED
*  Receiver COPIED
*  Receiver DELETED
*  Receiver DELETED
*  Receiver DELETED
*  Receiver COPIED
*  Receiver DELETED
*  Receiver DELETED
*  Receiver COPIED
*  Receiver COPIED
*  Receiver COPIED
*  Receiver COPIED
*  Receiver COPIED
*  Receiver COPIED
*  Receiver COPIED
*  Receiver COPIED
*  Receiver DELETED
*  Receiver DELETED
*  Receiver DELETED
*  Receiver DELETED
*  Receiver DELETED
*  Receiver DELETED
*  Receiver COPIED
*  Receiver DELETED
*  Receiver COPIED
*  Receiver DELETED
*  Receiver DELETED
*  Receiver COPIED
*  Receiver DELETED
*  Receiver DELETED
- Thread waked up
- Queue not empty, searching receivers ...
- Sending notification

Receive: Notification received: Testing

- Queue empty - sleeping 500ms
- Thread waked up
- Queue empty - sleeping 500ms
- Thread waked up
- Queue empty - sleeping 500ms
*  Receiver DELETED
*  Receiver DELETED

*** 1 failure detected in test suite ""FrameworkTests""
}}}

'''Why the ""receiver"" object has been copied many times and the final method has not been executed on the original object but on a copy which proves the check of the ""runCount""?'''

I have managed to go around this problem adding a shared_ptr<>

Following code (classes the same):
{{{
	NotificationCenter nCenter(NotificationCenter::NCT_DELAYED);
	boost::shared_ptr<NotificationReceived> receiver(new NotificationReceived);
	NotificationCenter::Signal* sig = nCenter.RegisterForNotification(NotificationCenter::Notification::NT_BROADCAST);
	sig->connect(boost::bind(&NotificationReceived::Receive, receiver, _1));


	nCenter.BroadcastNotification(NotificationCenter::Notification(NotificationCenter::Notification::NT_BROADCAST, ""Testing""));
	boost::this_thread::sleep(boost::posix_time::seconds(2));
	BOOST_REQUIRE_EQUAL(receiver->runCount, 1);
}}}

Outputs what I expected also from the first example:
{{{
*  Receiver CREATED
- Queue empty - sleeping 500ms
- Thread waked up
- Queue not empty, searching receivers ...
- Sending notification

Receive: Notification received: Testing

- Queue empty - sleeping 500ms
- Thread waked up
- Queue empty - sleeping 500ms
- Thread waked up
- Queue empty - sleeping 500ms
*  Receiver DELETED

*** No errors detected
}}}",Bugs,closed,To Be Determined,signals2,Boost 1.49.0,Problem,invalid,signals2 connect multiple objects copy,