C++ In a Nutshell

Name

mem_fun_ref function template — Creates a function object to call a member function via a reference

Synopsis

template<typename Rtn, typename T>
  const_mem_fun_ref_t<Rtn,T>
    mem_fun_ref(Rtn (T::*f)(  ) const);
template<typename Rtn, typename T, typename Arg>
  const_mem_fun1_ref_t<Rtn,T,Arg>
    mem_fun_ref(Rtn (T::*f)(Arg) const);
template<typename Rtn, typename T>
  mem_fun_ref_t<Rtn,T> mem_fun_ref(Rtn (T::*f)(  ));
template<typename Rtn, typename T, typename Arg>
  mem_fun1_ref_t<Rtn,T,A> mem_fun_ref(Rtn (T::*f)(Arg));

The mem_fun_ref function template takes a pointer to a member function as an argument and returns a function object that can call the member function. The function object must be applied to an object of type T (or a derived class). The object is passed by reference to the functional. The Rtn template parameter is the return type of the member function; the T template parameter is the object that has the member function. The optional Arg template parameter is the type of the argument to the member function.

The mem_fun_ref function is usually the simplest way to create a function object that wraps a member function. In normal use, the compiler deduces the template parameters.

Suppose you have an Employee class and a container of Employee objects. As in Example 13-11, one of the member functions of Employee is gets_bonus, which returns a bool: true if the employee is lucky and gets a bonus this year, or false if the employee is unlucky. Example 13-12 shows how to remove all the ...