Re: passing virtual member function to templates

From:

Victor Bazarov <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Tue, 17 Mar 2009 22:17:32 -0400

Message-ID:

<gppljv$hgs$1@news.datemas.de>

g3rc4n@gmail.com wrote:

is it possible to do something like this

template<class T, class FUN>
void foo(T& t, const FUN& f){
f(t);
}
template<class T, class FUN>
void fooo(T& t, const FUN& f){

Did you mean to name it differently?

t->f();

If 'f' is a member, then the syntax is

(t.*f)(); // notice the . not -> since your 't' is a ref

}
struct base{
  virtual ~base(){}
  virtual void say()=0;
};
struct dir : public base{
  void say(){
    std::cout << "hi" << std::endl;
  }
};
void bar(){
  base* ptr = new dir;
  foo(ptr,std::mem_fun(base::say));

You don't need 'std::mem_fun'. Try

foo(ptr, &base::say);

delete ptr;
}

or are virtual functons something that templates can't handle?

They should be able to. You got some cleanup to do in your code. Try
rewriting the second 'foo' template as

   template<class T, class F> void foo(T& t, F& f)
   {
      (t.*f)();
   }

V
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