#include <boost/signals2.hpp> 
#include <iostream> 

int func1() { return 1; } 
int func2() { return 2; } 

int main() 
{ 
  boost::signals2::signal<int ()> s; 
  s.connect(func1); 
  s.connect(func2); 
  std::cout << *s() << std::endl; 
}