iOS 6.1 Dynamic Library build and link

Question

I am trying to create a dynamic library for iOS and load it at runtime. After taking a look at this question and this answer, I have been doing it using iOSOpenDev and deploying everything on my iPhone. The xCode project for the dylib is called KDylibTwo and the files I modiefied are: KDylibTwo.h ``` #import @interface KDylibTwo : NSObject -(void)run; @end ``` KDylibTwo.m ``` #import "KDylibTwo.h" @implementation KDylibTwo -(id)init { if ((self = [super init])) { } return self; } -(void)run{ NSLog(@"KDylibTwo loadded."); } @end ``` In order to test if my library works, after building it for profiling (the way iOSOpenDev deploys it on iPhone), I can find it stored on my device at `/usr/lib/libKDylibTwo.dylib` and built a tweak (again using iOSOpenDev), hooking the SpringBoard as follows: ``` #include %hook SBApplicationIcon -(void)launch{ NSLog(@" SBHook For libKDylibTwo.dylib"); void* dylibLink = dlopen("/usr/lib/libKDylibTwo.dylib", RT…

Accepted Answer

As Victor Ronin pointed out, "dlsym" is for C symbols. To obtain objective-C class from dylib that you linked at runtime you can use objc runtime functions. In your case:

```
void* dylibLink = dlopen("/usr/lib/libKDylibTwo.dylib", RTLD_NOW);
id KDylibTwo = [[objc_getClass("KDylibTwo") alloc] init];
[KDylibTwo run];
```

First line is linking your library at runtime. This is required in order to use code inside of it.

Second line creates instance of class `KDylibTwo`. `objc_getClass` function returns class object that you can later use to create instances of this class like you would with any objective-C class - using `alloc` and `init` methods. Once you obtained class object with `objc_getClass` you can work with him like nothing happend. At this point you can forget that you dynamically linked you library at runtime.

Third line is calling `run` method. As you can see, it's normal objective-C syntax. Nothing is changed because you linked your library at runtime. You can call any method you want.

iOS 6.1 Dynamic Library build and link

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