cls和selfcls 指向同一个地址(RuntimeViewController类对象)。
按照oc的类结构,[self class]不是应该指向RuntimeViewController的元类吗?
Look at this and you will understandhttp://xiongzenghuidegithub.github.io/blog/2016/05/17/runtime-part7-object-getclass-yu-object-class-de-qu-bie/
//实例对象调用class时返回isa指向的objc_object -class { return (id)isa; } //类对象调用class时返回类对象自己 +class { return self; } //取自Object.h Object.m
Look at this and you will understand
http://xiongzenghuidegithub.github.io/blog/2016/05/17/runtime-part7-object-getclass-yu-object-class-de-qu-bie/