id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
12483	signals2 bind to member function by value fail to signal when using trackable	kim.lykke.johansen@…	Douglas Gregor	"In my trail to learn and get comfortable with signals2 I wrote a small test program.
In this program I encountered what I believe to be inconsistency in the way that signals2 connect to member functions when using bind, when using trackable aswell.
{{{
#!div style=""font-size: 80%""
Test program:
  {{{#!c++
#include ""boost/signals2.hpp""
#include <iostream>


class SignalTest : public boost::signals2::trackable
{
public:
	SignalTest() {};

	void printInfo(const std::string name, int num)
	{
		std::cout << ""Signal: "" << name << "" "" << num << std::endl;
	}
};

int main()
{
	boost::signals2::signal<void (const std::string&, int)> sig;

	SignalTest test1;
	sig.connect(boost::bind(&SignalTest::printInfo, test1, _1, _2));
	sig(""Test"", 1);

	{
		SignalTest test2;
		sig.connect(boost::bind(&SignalTest::printInfo, test2, _1, _2));
		sig(""Test"", 2);
	}

	return 0;
}
  }}}
}}}

The code above compiles and running it I'd expect both signals to be printed, however nothing is printed.
If however I bind the signalTest object ""test2"" by reference like the code below:
{{{
#!div style=""font-size: 80%""
Bind by reference:
  {{{#!c++
sig.connect(boost::bind(&SignalTest::printInfo, &test2, _1, _2));
  }}}
}}}
The following is printed:
{{{
#!div style=""font-size: 80%""
test2 bind by reference print
  {{{#!text
Signal: Test 2
  }}}
}}}

And if I also bind signalTest object ""test1"" by reference the following is printed:
{{{
#!div style=""font-size: 80%""
test1 and test2 bind by reference print
  {{{#!text
Signal: Test 1
Signal: Test 2
Signal: Test 2
  }}}
}}}


As I was lead to understand from the example code of section ""Automatic Connection Management"" in the tutorial at http://www.boost.org/doc/libs/1_61_0/doc/html/signals2/tutorial.html#idp394616720 I should be able to call the member function by value, however this is not the case using trackable.

"	Support Requests	new	To Be Determined	signals	Boost 1.61.0	Not Applicable		signals2 trackable bind