C++ Is it possible to have a generic function pointer?

Question

In C++ is it possible to make some sort of generic function pointer that points to any function that returns a pointer to some type and takes no arguments?

Eg, one type

Answer 1

The standard does not allow such thing. You may or may not be able to get away with casting your function pointer to void* (*)(). In C++ there are standard-conforming solutions. Here is a simple pre-C++11 one:

struct MyFunc
{
  virtual void* operator()() = 0;
  virtual ~Myfunc(){}
};

template 
struct MyfuncImpl
{
  typedef T TFunc();
  MyfuncImpl (TFunc* func) : m_func(func) {}
  void* operator()() { return m_func(); }
 private:
  TFunc* m_func;
};

Now you can store shared_ptr in your vector.

A much nicer solution in C++11 could look like this:

template 
std::function castToVoidFunc (T* (*func)())
{
  return [=](){ return func(); };
}