sigc_test.cpp

#include <iostream>
#include <sigc++/signal.h>

using namespace std;

class A {
public:
  sigc::signal<void()> s1;
};

class B {
  public:
    ~B() { cout << "B::~B()" << endl; }
    void onS1() { cout << "B::onS1: SHOULD NOT PRINT" << endl; }
};

class C: public sigc::trackable {
  public:
    ~C() { cout << "C::~C()" << endl; }
    void onS1() { cout << "WILL NOT PRINT" << endl; }
};


int main() {
  A a;
  B* b = new B;
  C* c = new C;

  a.s1.connect(sigc::mem_fun(*b, &B::onS1));
  a.s1.connect(sigc::mem_fun(*c, &C::onS1));
  delete b;
  delete c;
  a.s1.emit();
}

// $ g++ -std=c++11 `pkg-config --cflags --libs sigc++-2.0` sigc_test.cpp
// $ ./a.out
// B::~B()
// C::~C()
// B::onS1: SHOULD NOT PRINT