iOS开发之单例使用（宏）

.h文件中

#define SKSingletonH(__className)\+ (__className *)shareInstance;\

.m文件中

#define SKSingletonM(__className)\\static __className *_instance = nil;\\+ (__className *)shareInstance {\    static dispatch_once_t onceToken;\    dispatch_once(&onceToken, ^{\        _instance = [[self alloc] init];\    });\    return _instance;\}\\+ (instancetype)allocWithZone:(struct _NSZone *)zone {\    static dispatch_once_t onceToken;\    dispatch_once(&onceToken, ^{\        _instance = [super allocWithZone:zone];\    });\    return _instance;\}\\- (id)copy {\    return _instance;\}\\- (id)mutableCopy {\    return _instance;\}\