Qt中常用宏定义

一、Q_DECLARE_PRIVATE(Class)

#define Q_DECLARE_PRIVATE(Class) 
  inline Class##Private* d_func() 
  { 
      # 此处的 d_ptr 是属于QObject类中的私有成员变量
      Q_CAST_IGNORE_ALIGN(return reinterpret_cast<Class##Private *>(qGetPtrHelper(d_ptr));)           
  } 
  
  inline const Class##Private* d_func() const 
  { 
  	Q_CAST_IGNORE_ALIGN(return reinterpret_cast<const Class##Private *>(qGetPtrHelper(d_ptr));) 
  } 
     
  friend class Class##Private;

二、Q_DECLARE_PRIVATE_D(Dptr, Class)

#define Q_DECLARE_PRIVATE_D(Dptr, Class) 
    inline Class##Private* d_func() 
    {
    	 Q_CAST_IGNORE_ALIGN(return reinterpret_cast<Class##Private *>(qGetPtrHelper(Dptr));) 
    } 
    
    inline const Class##Private* d_func() const 
    {
        Q_CAST_IGNORE_ALIGN(return reinterpret_cast<const Class##Private *>(qGetPtrHelper(Dptr));) 
    } 
    
    friend class Class##Private;

三、Q_DECLARE_PUBLIC(Class)

#define Q_DECLARE_PUBLIC(Class)                                    
    inline Class* q_func() 
    {
     	return static_cast<Class *>(q_ptr); 
    } 
    
    inline const Class* q_func() const
    { 
     	return static_cast<const Class *>(q_ptr); 
    } 
    
    friend class Class;

四、Q_D(Class) 和 Q_Q(Class)

#define Q_D(Class) Class##Private * const d = d_func()
#define Q_Q(Class) Class * const q = q_func()