![obj-c
• [self class] or [super class]
• self
• super “ ” self
super
class](https://image.slidesharecdn.com/objc-self-super-110123204605-phpapp02/85/self-and-super-in-objc-5-320.jpg)
![objc_msgSend
•
• id objc_msgSend(id theReceiver, SEL
theSelector, ...)
• [self class]
• theReceiver -> self
• SEL -> class](https://image.slidesharecdn.com/objc-self-super-110123204605-phpapp02/85/self-and-super-in-objc-8-320.jpg)
![objc_msgSendSuper
•
• id objc_msgSendSuper(struct objc_super
*super, SEL op, ...)
• [super class]
• objc_super -> some struct?
• SEL -> class](https://image.slidesharecdn.com/objc-self-super-110123204605-phpapp02/85/self-and-super-in-objc-9-320.jpg)
![objc_msgSendSuper
• [super class]
• objc_super receiver =
self superClass = Base
• objc_msgSendSuper
objc_super -> superClass selector
• selector objc_super ->
receiver](https://image.slidesharecdn.com/objc-self-super-110123204605-phpapp02/85/self-and-super-in-objc-11-320.jpg)
![That is ...
• [self class]
• objc_msgSend(receiver, class)
• receiver = Derived, “class” selector is from
NSObject
• [super class]
• objc_msgSendSuper(objc_super, class)
• ==> objc_msgSend(objc_super -> receiver, class)
• receiver = Derived, “class” selector is from
NSObject
• NSObject class receiver class](https://image.slidesharecdn.com/objc-self-super-110123204605-phpapp02/85/self-and-super-in-objc-12-320.jpg)
![That is ...
• [self class]
• objc_msgSend(receiver, class)
• receiver = Derived, class method is from NSObject
• [super class]
• objc_msgSendSuper(objc_super, class)
So ...
• [self class] ‘s output is Derived
==> objc_msgSend(objc_super -> receiver,
class) class] ‘s output is Derived too !
[super
• receiver = Derived, class method from NSObject
• NSObject class receiver class](https://image.slidesharecdn.com/objc-self-super-110123204605-phpapp02/85/self-and-super-in-objc-13-320.jpg)
![How to get super
class’s name?
• [self superclass]
• NSLog(@"super class is %@", [self
superclass]);
• The output is “Base” !](https://image.slidesharecdn.com/objc-self-super-110123204605-phpapp02/85/self-and-super-in-objc-14-320.jpg)
self and super in objc
- 1. Obj-C self super twitter:@vonbo
- 4. self class is Derived super class is Derived
- 5. obj-c • [self class] or [super class] • self • super “ ” self super class
- 6. C -1 • Sending Messages • When it encounters a method invocation, the compiler might generate a call to any of several functions to perform the actual message dispatch, depending on the receiver, the return value, and the arguments. • You can use these functions to dynamically invoke methods from your own plain C code, or to use argument forms not permitted by NSObject’s perform… methods. These functions are declared in /usr/include/objc/objc-runtime.h.
- 7. C -2 • objc_msgSend sends a message with a simple return value to an instance of a class. • objc_msgSend_stret sends a message with a data- structure return value to an instance of a class. • objc_msgSendSuper sends a message with a simple return value to the superclass of an instance of a class. • objc_msgSendSuper_stret sends a message with a data-structure return value to the superclass of an instance of a class.uperclass of an instance of a class.
- 8. objc_msgSend • • id objc_msgSend(id theReceiver, SEL theSelector, ...) • [self class] • theReceiver -> self • SEL -> class
- 9. objc_msgSendSuper • • id objc_msgSendSuper(struct objc_super *super, SEL op, ...) • [super class] • objc_super -> some struct? • SEL -> class
- 10. objc_super struct objc_super { id receiver; Class superClass; }
- 11. objc_msgSendSuper • [super class] • objc_super receiver = self superClass = Base • objc_msgSendSuper objc_super -> superClass selector • selector objc_super -> receiver
- 12. That is ... • [self class] • objc_msgSend(receiver, class) • receiver = Derived, “class” selector is from NSObject • [super class] • objc_msgSendSuper(objc_super, class) • ==> objc_msgSend(objc_super -> receiver, class) • receiver = Derived, “class” selector is from NSObject • NSObject class receiver class
- 13. That is ... • [self class] • objc_msgSend(receiver, class) • receiver = Derived, class method is from NSObject • [super class] • objc_msgSendSuper(objc_super, class) So ... • [self class] ‘s output is Derived ==> objc_msgSend(objc_super -> receiver, class) class] ‘s output is Derived too ! [super • receiver = Derived, class method from NSObject • NSObject class receiver class
- 14. How to get super class’s name? • [self superclass] • NSLog(@"super class is %@", [self superclass]); • The output is “Base” !
- 15. The End