text: //
  //  Macro.h
  //  Mr
  //
  //  Created by FanFamily on 15/3/15.
  //  Copyright (c) 2015年 familymrfan. All rights reserved.
  //
  
  #ifndef Mr_Macro_h
  #define Mr_Macro_h
  
  #define SHARED_OBJECT(class_name) \
  do { \
  static class_name* once = nil; \
  static dispatch_once_t onceToken; \
  dispatch_once(&onceToken, ^{ \
  once = [[class_name alloc] init]; \
  }); \
  return once; \
  } while (0)
  
  #endif
  