c++ - Boost Connect Signal From one class to another -

i need emit signal child class it's parent class when asynchronous operation finished using boost signal,

for example parent class

class {     void dotask(){       class b child;       child.asynchtask();     }      void onfinished(){       //invoke when async task finished     } }; 

and second class

class b {      void asynchtask(){      //async task start  here       }   void asynchtaskfinished(){       // emit signal here invoke onfinished() of parent class      }  }; 

how can using boost signal, found example , post complete example using boost::signals c++ eventing, couldn't figure out how implement in case.

any appreciated.

thanks haris