class button
{
public:
 
    boost::function<void> onClick;
};
 
class player
{
public:
 
    void play();
    void stop();
};
 
button playButton, stopButton;
player thePlayer;
 
void connect()
{
    playButton.onClick = boost::bind(&player::play, &thePlayer);
    stopButton.onClick = boost::bind(&player::stop, &thePlayer);
 
    // Calls player::play() on thePlayer object
    playButton.onClick();
}