title: How to get a method's address in a class?
body: <p>Here is part of my code:</p>
  
  <p>In a.h:</p>
  
  <pre><code>class classA
  {
  public:
  void (*function_a)(void);
  classA();
  void function_a();
  };
  </code></pre>
  
  <p>In a.cpp:</p>
  
  <pre><code>void classA::classA()
  {
    (*function_a)() = function_a;
  }
  
  void classA::function_a()
  {
    return;
  }
  </code></pre>
  
  <p>I want to get function_a's address and save it into void (*function_a)(void), but I got compile error that "expression is not assignable". What shall I do to solve this problem?</p>