c++ - boost::function 类

Question

我想实现一个类似于 boost::function 的类 Function，类 Function 可以在 main.cpp 中这样使用：

#include <iostream>
#include "Function.hpp"

int funct1(char c)
{
   std::cout << c << std::endl;
   return 0;
}

 int main()
 {
   Function<int (char)> f = &funct1;
   Function<int (char)> b = boost::bind(&funct1, _1);
   f('f');
   b('b');
   return 0;
 }

在我的 Function.hpp 中，我有

 template <typename T>
 class Function;

 template <typename T, typename P1>
 class Function<T(P1)>
 {
    typedef int (*ptr)(P1);
    public:

    Function(int (*n)(P1)) : _o(n)
   {
   }

   int           operator()(P1 const& p)
   {
     return _o(p);
   }

   Function<T(P1)>&      operator=(int (*n)(P1))
   {
     _o =  n;
     return *this;
   }

  private:
  ptr           _o; // function pointer
  };

上面的代码适用于 Function f = &funct1，
但不适用于 Function b = boost::bind(&funct1, _1);
我想知道 boost::Function 究竟是如何工作的，以及我能做些什么来支持我的 Function 支持 boost::bind

Answer 1

I wrote sample program for type erasure: http://prograholic.blogspot.com/2011/11/type-erasure.html. In this article I made sample class (unfortunately this article written in Russian, but I think that code samples may help you)