Call function pointer in an object inside a Vector

I am trying to implement Observers and a Subject design pattern...

I have a object Subject, with a vector of pointers to Observers. Each Observer has a pointer to a function. How do I call it?

In this class, it's defined the function that I want to call

class functions_class
{
  static bool getVal(){
     return true;
  }
};

In this class, the vector containing the observer is defined

class Subject
{
      vector<Observer*> mViews;

   public:
      void addObserver(Observer *o)
      {
         mViews.push_back(o)
      }
};

In this class, the function pointer is stored. There is a function to call this pointer

class Observer
{
   typedef bool(*boolPtr)(void);
   boolPtr mPtr;

   Observer(boolPtr ptr)
   {
      mPtr = ptr;
   }

   bool call()
   {
      return (mPtr)();
   }
};

This is where objects are created

    Subject s;
    Observer o(functions_class::getVal);
    s.addObserver(&o);

QUESTION......... How do I call the function pointer in observer?? I'm using a generic function in observer, but I can't make it work.

I tried:

(s.mViews[0].call)()

Any idea?

Is it also possible to cast the output of the function call to an uint32_t?