https://github.com/ming1016/study/wiki/Objc-Runtime

 

先看看isKindOfClass和isMemberOfClass在Object.mm中的实现

- (BOOL)isKindOf:aClass
{
     Class cls;
     for (cls = isa; cls; cls = cls->superclass)
          if (cls == (Class)aClass)
               return YES;
     return NO;
}

- (BOOL)isMemberOf:aClass
{
     return isa == (Class)aClass;
}