__attribute__

• objc_subclassing_restricted

定义一个 不可被继承的类，如下代码，在 @interface WBTools : NSObject 前面加上 __attribute__((objc_subclassing_restricted)) 即可

__attribute__((objc_subclassing_restricted))
@interface WBTools : NSObject
@end

@implementation WBTools
@end

/** ❌ Cannot subclass a class that was declared with the 'objc_subclassing_restricted' attribute */
@interface WBNetworkTools : WBTools
@end

@implementation WBNetworkTools
@end

• objc_requires_super

NS_REQUIRES_SUPER 标识子类继承父类方法时，需要调用 [super xxMethod] 方法，否则给出编译警告 ⚠️

@interface WBTools : NSObject
/** 写法一 */
- (void)initialize __attribute__((objc_requires_super));
/** 写法二 */
- (void)wb_initialize NS_REQUIRES_SUPER;
@end

@implementation WBTools
- (void)initialize { }
- (void)wb_initialize { }
@end

@interface WBNetworkTools : WBTools

@end

@implementation WBNetworkTools
- (void)initialize {
    /** ⚠️ Method possibly missing a [super initialize] call */
}
- (void)wb_initialize {
    /** ⚠️ Method possibly missing a [super wb_initialize] call */
}

@end