iOS开发常用宏定义

#pragma mark - 实例定义
#define SingletenInterface + (instancetype)sharedInstance;

#pragma mark - 定义单例代码块
#define SingletenImpl static id _instace; + (id)allocWithZone:(struct _NSZone *)zone {     static dispatch_once_t onceToken;     dispatch_once(&onceToken, ^{         _instace = [super allocWithZone:zone];     });     return _instace; } - (id)copyWithZone:(NSZone *)zone {     return _instace; } + (instancetype)sharedInstance {     static dispatch_once_t onceToken;     dispatch_once(&onceToken, ^{         _instace = [[self alloc] init];     });     return _instace; }