尽管没有虚函数，对虚表的未定义引用

我有一个基类和一个派生类，angelic_wing(派生类)和angelic_event(基类)。当我编译时，得到以下两个错误:

/tmp/ccG6KlZF.o: In function `angelic_wing::angelic_wing()':
angelicwing.cpp:(.text+0x20): undefined reference to `vtable for angelic_wing'
/tmp/ccG6KlZF.o: In function `angelic_wing::~angelic_wing()':
angelicwing.cpp:(.text+0x90): undefined reference to `vtable for angelic_wing'
collect2: error: ld returned 1 exit status

在做了一些研究之后，问题似乎与没有在基类中定义虚函数的主体有关。然而，由于以下原因，这个问题似乎并非如此:

1. 这些是派生类的构造函数和析构函数，因此不会在碱中被声明或定义类。
的构造函数和析构函数都没有派生类或基类被声明/定义为virtual。

当然，我在基类中使用虚函数。下面是代码:

class angelic_event{
public:
  angelic_event();
  ~angelic_event();
  virtual void events(SDL_Event *event);
  virtual void input_focus();
  virtual void input_blur();
  virtual void key_down(SDLKey sym, SDLMod mod, Uint16 unicode);
  virtual void key_up(SDLKey sym, SDLMod mod, Uint16 unicode);
  virtual void mouse_focus();
  virtual void mouse_blur();
  virtual void mouse_move(int x, int y, int rx, int ry, int left, int right, int middle);
  virtual void mouse_wheel(int up, int down);
  virtual void ml_button_down(int x, int y);
  virtual void ml_button_up(int x, int y);
  virtual void mr_button_down(int x, int y);
  virtual void mr_button_up(int x, int y);
  virtual void mm_button_down(int x, int y);
  virtual void mm_button_up(int x, int y);
  virtual void joy_axis(Uint8 which, Uint8 axis, Sint16 value);
  virtual void joy_button_down(Uint8 which, Uint8 button);
  virtual void joy_button_up(Uint8 which, Uint8 button);
  virtual void joy_hat(Uint8 which, Uint8 hat, Uint8 value);
  virtual void joy_ball(Uint8 which, Uint8 ball, Sint16 rx, Sint16 ry);
  virtual void minimize();
  virtual void restore();
  virtual void resize(int w, int h);
  virtual void expose();
  virtual void flag_exit();
  virtual void user_event(Uint8 type, int code, void *data1, void *data2);
};

然而，据我所知，我已经在events.cpp文件中定义了所有这些函数。还要注意，类的构造函数和析构函数都不是虚函数。 另一方面，我的派生类根本没有声明任何虚函数。下面是它的代码:

class angelic_wing : angelic_event{
  int game_state;
  int current_state;
  angelic_clock game_clock;
  int newtime;
  int oldtime;
  SDL_Event event;
  SDL_Surface *screen;
private:
  void init_bootstrap();
  void init_mainmenu();
  void init_pausemenu();
  void init_gameover();
  void init_gamewin();
  void init_gamecredits();
  void init_gameproper();
private:
  void flag_exit();
  void user_event(Uint8 type, int code, void *data1, void *data2);
public:
  angelic_wing();
  ~angelic_wing();
  int execute();
  int initiate();
  int destruct();
  int process_event(SDL_Event *event);
  int update();
  int render();
  int game_state_init(int current_state);
  int check_time(float elapsed);
};

如您所见，没有一个虚函数。我不确定发生了什么，但我遇到的大多数信息都说要确保我已经定义了所有的函数。然而，我不能重复检查，而且我确实已经定义了所有这些。所以我没有选择了。

然而，我认为有一件事可能与此相关。我认为将angelic_event类的虚拟函数和angelic_wing类的覆盖函数保留在相同的events.cpp文件中是一个好主意。然而，在这样做之后，我怀疑，也许是一些奇怪的巧合，这导致了"对angelic_wing的vtable的未定义引用"错误。

因此，我将重写的函数移到了angelicwing.cpp文件中，但无济于事。

下面是events.cpp文件的完整代码，以防你们能捕捉到我错过的东西:

#include "events.hpp"
#include "angelicwing.hpp"
angelic_event :: angelic_event(){}
angelic_event :: ~angelic_event(){}
void angelic_event :: events(SDL_Event *event)
{
  switch(event->type){
  case SDL_ACTIVEEVENT:
    switch(event->active.state){
    case SDL_APPMOUSEFOCUS:
      if(event->active.gain){
        mouse_focus();
      } else {
        mouse_blur();
      } break;
    case SDL_APPINPUTFOCUS:
      if(event->active.gain){
        input_focus();
      } else {
        input_blur();
      } break;
    case SDL_APPACTIVE:
      if(event->active.gain){
        restore();
      } else {
        minimize();
      } break;
    } break;
  case SDL_KEYDOWN:
    key_down(event->key.keysym.sym, event->key.keysym.mod, event->key.keysym.unicode);
    break;
  case SDL_KEYUP:
    key_up(event->key.keysym.sym, event->key.keysym.mod, event->key.keysym.unicode);
  case SDL_MOUSEMOTION:
    mouse_move(event->motion.x, event->motion.y, event->motion.xrel, event->motion.yrel,
               (event->motion.state&SDL_BUTTON(SDL_BUTTON_LEFT))!=0,
               (event->motion.state&SDL_BUTTON(SDL_BUTTON_RIGHT))!=0,
               (event->motion.state&SDL_BUTTON(SDL_BUTTON_MIDDLE))!=0);
    break;
  case SDL_MOUSEBUTTONDOWN:
    switch(event->button.button){
    case SDL_BUTTON_LEFT:
      ml_button_down(event->button.x, event->button.y);
      break;
    case SDL_BUTTON_RIGHT:
      mr_button_down(event->button.x, event->button.y);
      break;
    case SDL_BUTTON_MIDDLE:
      mm_button_down(event->button.x, event->button.y);
      break;
    } break;
  case SDL_MOUSEBUTTONUP:
    switch(event->button.button){
    case SDL_BUTTON_LEFT:
      ml_button_up(event->button.x, event->button.y);
      break;
    case SDL_BUTTON_RIGHT:
      mr_button_up(event->button.x, event->button.y);
      break;
    case SDL_BUTTON_MIDDLE:
      mm_button_up(event->button.x, event->button.y);
      break;
    } break;
  case SDL_JOYAXISMOTION:
    joy_axis(event->jaxis.which, event->jaxis.axis, event->jaxis.value);
    break;
  case SDL_JOYBALLMOTION:
    joy_ball(event->jball.which, event->jball.ball, event->jball.xrel, event->jball.yrel);
    break;
  case SDL_JOYHATMOTION:
    joy_hat(event->jhat.which, event->jhat.hat, event->jhat.value);
    break;
  case SDL_JOYBUTTONDOWN:
    joy_button_down(event->jbutton.which, event->jbutton.button);
    break;
  case SDL_JOYBUTTONUP:
    joy_button_up(event->jbutton.which, event->jbutton.button);
    break;
  case SDL_QUIT:
    flag_exit();
    break;
  case SDL_SYSWMEVENT:
    // ignore?
    break;
  case SDL_VIDEORESIZE:
    resize(event->resize.w, event->resize.h);
    break;
  case SDL_VIDEOEXPOSE:
    expose();
    break;
  default:
    user_event(event->user.type, event->user.code, event->user.data1, event->user.data2);
    break;
  };
}
void angelic_event :: input_focus(){}
void angelic_event :: input_blur(){}
void angelic_event :: key_down(SDLKey sym, SDLMod mod, Uint16 unicode){}
void angelic_event :: key_up(SDLKey sym, SDLMod mod, Uint16 unicode){}
void angelic_event :: mouse_focus(){}
void angelic_event :: mouse_blur(){}
void angelic_event :: mouse_move(int x, int y, int rx, int ry, int left, int right, int middle){}
void angelic_event :: mouse_wheel(int up, int down){}
void angelic_event :: ml_button_down(int x, int y){}
void angelic_event :: ml_button_up(int x, int y){}
void angelic_event :: mr_button_down(int x, int y){}
void angelic_event :: mr_button_up(int x, int y){}
void angelic_event :: mm_button_down(int x, int y){}
void angelic_event :: mm_button_up(int x, int y){}
void angelic_event :: joy_axis(Uint8 which, Uint8 axis, Sint16 value){}
void angelic_event :: joy_button_down(Uint8 which, Uint8 button){}
void angelic_event :: joy_button_up(Uint8 which, Uint8 button){}
void angelic_event :: joy_hat(Uint8 which, Uint8 hat, Uint8 value){}
void angelic_event :: joy_ball(Uint8 which, Uint8 ball, Sint16 rx, Sint16 ry){}
void angelic_event :: minimize(){}
void angelic_event :: restore(){}
void angelic_event :: resize(int w, int h){}
void angelic_event :: expose(){}
void angelic_event :: flag_exit(){}
void angelic_event :: user_event(Uint8 type, int code, void *data1, void *data2){}
void angelic_wing :: user_event(Uint8 type, int code, void *data1, void *data2)
{
  switch(code){
  case CHANGE_GAME_MODE:
    game_state = *((int *)data1);
    break;
  default:
    break;
  }
}

另外，如果它可能有帮助，我应该告诉你一些关于我的系统。我使用的是GCC版本4.8.2(尽管我是用g++命令编译的)。我在64位系统上运行Slackware Version 14.1，没有32位兼容性文件等。

我必须说，这对我来说真是一个头痛的问题。希望你们这些更有经验的人能告诉我我做错了什么，或者可能是一个前进的方法。

非常感谢你的时间，Jose Luis A. Nunez