iOS开发笔记之宏定义单例方法

#define SINGLETON_FOR_CLASS(classname) \

\

+ (classname*) shareInstance \

{ \

static dispatch_once_t pred = 0; \

__strong static classname* _sharedObject = nil; \

dispatch_once(&pred, ^{ \

_sharedObject = [[self alloc] init]; \

}); \

return _sharedObject;\

}