Singleton 头文件

//.h文件

#define SingletonH(name) \

+(instancetype) shared##name ;

//.m文件

#define SingletonM(name) \

static id instance##name; \

+(instancetype) shared##name { \

return [[self allocWithZone:nil]init]; \

} \

+(instancetype)allocWithZone:(struct _NSZone *)zone{ \

static dispatch_once_t onceToken; \

dispatch_once(&onceToken, ^{ \

instance##name = [super allocWithZone:zone]; \

}); \

return instance##name; \

} \

+(instancetype)alloc { \

return [self allocWithZone:nil];\

}