objective-c-runtime

I'm trying to implement a basic object-oriented ANSI C runtime and using Objective-C as a guide. They're seems to be three parts. A Class Description, Class Interface, and Class Implementation. In order for the Class Interface to be instantiated, the familiar method of using the Class object to instantiate one's object can only happen if the runtime has already instantiated your class object using the class description. So are all Class definitions allocated statically at first run to provide the ability to instantiate using the Class object? Or if they are allocated dynamically (on initial

If I have a call from within a random class like this: @implementation SomeClass - (void) classMethodFoo { int a = [SomeSingleton sharedInstance].aValue; } @end Inside SomeSingleton sharedInstance , is there a way to get a reference to the object which called this method (without the called passing self as a parameter of course)? No, information about the caller isn't passed along automatically. This is why IBAction methods, for instance, have a sender parameter, and why delegate methods often have a parameter that refers to the delegate's object. 来源： https://stackoverflow.com/questions

I've been looking for a way to use optional protocol methods and have clean code. In other words: 1: No respondsToSelector: calls all over my code 2. Should work for any method signature, so a category method on NSObject making the check and calling performSelector: is out (and NSInvocation has problems cooperating with ARC) 3: This solution , IMO, pretends to be universal but has all the drawbacks of 1 I eventually came up with this idea: @protocol MyProtocol <NSObject> @optional -(void)optionalMethod; @end @interface ClassA : NSObject <MyProtocol> @end @implementation ClassA -(void

I am having problem understanding part of the function of "selectors", as described in Apple's guide. I've bolded the parts where I am getting confused: In Objective-C, selector has two meanings. It can be used to refer simply to the name of a method when it’s used in a source-code message to an object. It also, though, refers to the unique identifier that replaces the name when the source code is compiled. Compiled selectors are of type SEL. All methods with the same name have the same selector. You can use a selector to invoke a method on an object—this provides the basis for the

To give a bit of context of why I'm asking this: basically I would like to change the location of the myLocationButton of the google map on iOS. So I first fetch the actual button like so: @implementation GMSMapView (UIChanges) - (UIButton *)myLocationButton { UIButton *myLocationButton; for (myLocationButton in [settingView subviews]) { if ([myLocationButton isMemberOfClass:[UIButton class]]) break; } return myLocationButton; } Then I try to change it's position in the screen using NSLayoutConstraints (directly changing values of the frame property of the button does nothing with google maps

While doing some messing around with vector types and the ObjC runtime, I came across a very perplexing problem. Neither clang or GCC will give the 'proper' type-encoding for any SIMD vector type, as far as I can tell. #import <Foundation/Foundation.h> int main() { typedef int int4 __attribute__((vector_size(16))); typedef float float4 __attribute__((vector_size(16))); NSLog(@"Int4: %s", @encode(int4)); NSLog(@"Float4: %s", @encode(float4)); } When compiled & run with either GCC or clang, I get the following output: 2014-04-09 06:21:01.102 test[1707:507] Int4: 2014-04-09 06:21:01.103 test[1707