非议MFC（一）宏和类型定义的困惑

非议MFC（一）宏和类型定义的困惑

关键字：C++,MFC,宏,macro,define,typedef

有感于MFC库代码之去简就繁、之故弄玄虚，作下文，聊博一笑。

请看一段常见的代码：

//in user.h

class CTest

{

private:

int x;

public:

void SetX(int setX);

int GetX() const;

operator int *();

operator const int *() const;

void * GetSafeHandle() const;

};

//in user.cpp

#include "user.h"

void CTest::SetX(int setX)

{

x=setX;

}

//...

我们（MFC的作者）认为这样的代码太浅显，不够深沉，缺少内涵，没有嚼劲。赶快include我们的头文件吧，它可以提高代码的整体形象。我们的口号是：让蓝色关键字在屏幕上消失。

//in minimfc.h

#define USER_CLASS class

#define BEGIN_CLASS_DECLARATION {

#define END_CLASS_DECLARATION };

#define PRIVATE_MEMBER private:

#define PROTECTED_MEMBER protected:

#define PUBLIC_MEMBER public:

#define OPERATOR_OVERLOAD operator

#define CONSTANT_MEMBER_FUNTION const

#define BEGIN_FUNCTION_DEFINITION {

#define END_FUNCTION_DEFINITION }

typedef void AFX_RETURN_VOID_FUNCTION;

typedef int INT;

typedef int * LPINT;

typedef const int * LPCINT;

typedef void * HOBJ;

看！我们做到了。从此，我们的客户代码将这样写：

//in user.h

#include "minimfc.h"

USER_CLASS CTest

BEGIN_CLASS_DECLARATION

PRIVATE_MEMBER

INT x;

PUBLIC_MEMBER

AFX_RETURN_VOID_FUNCTION SetX(INT setX);

INT GetX() CONSTANT_MEMBER_FUNTION;

OPERATOR_OVERLOAD LPINT();

OPERATOR_OVERLOAD LPCINT() CONSTANT_MEMBER_FUNTION;

HOBJ GetSafeHandle() CONSTANT_MEMBER_FUNTION;

END_CLASS_DECLARATION

//in user.cpp

#include "user.h"

AFX_RETURN_VOID_FUNCTION CTest::SetX(INT setX)

BEGIN_FUNCTION_DEFINITION

x=setX;

END_FUNCTION_DEFINITION

//...